Atypical Proliferative Serous Tumor Research Articles

Long term follow-up of a large series of stage-II/III atypical proliferative serous ovarian tumors

BackgroundThe aim of this study was to assess prognostic factors and implications on further management in a large series of stage-II or III Atypical Proliferative Serous Tumors (APST) with a long-term follow-up. Patients and methodsPatients with APSTs and peritoneal implants treated in, or referred to, our institution were retrospectively reviewed. Prognostic factors on invasive recurrence, disease-free (DFS) and overall survival (OS) were analyzed. ResultsBetween 1971 and 2017, 212 patients were identified and followed (33 having invasive implants). After a median follow-up of 115 months, 70 recurrences were observed, 28 of them under the form of invasive disease. DFS at 5 years and 10 years was 73% and 62% respectively. The use of a conservative treatment (HR = 5.5[3.33–9.08], p < .0001), the presence of ≥3 peritoneal sites with implants (HR = 1.65[1.01–2.72], p = .045) were unfavorable prognostic factors for DFS. The presence of ≥3 peritoneal sites with implants (HR = 3.02[0.96–9.53], p = .049) and the presence of stromal microinvasion (HR = 3.19[1.12–9.1], p = .022) were unfavorable prognostic factors for OS. Non-conservative surgery (HR = 7[2.35–20.87], p = .0002), invasive implants (HR = 5.37[1.29–22.26], p = .013), and ≥ 3 peritoneal sites with implants (HR = 3.56 [1.11–11.39], p = .024) were identified as predictors of recurrence in the form of an invasive disease. Invasive implants were not associated with DFS (HR = 1.39[0.77–2.51], p = .27), nor OS (HR = 1.76[0.57–5.47], p = .32). ConclusionAfter a long-term follow-up, type of peritoneal implants is no longer a prognostic factor for OS. Implants ≥3 peritoneal sites seem to impact significantly OS and then require a specific follow-up in this subgroup of patients.

Importance of serous intraepithelial ovarian tubal carcinomas in the occurrence of "high-grade" serous carcinomas and / or peritoneal serous carcinomas of unknown primary origin.

Studies of the recent decades on serous pelvic adenocarcinomas in women have set the goal of distinguishing between two diagnostic units: "low-grade" and "high-grade" carcinomas. The predecessor of the "low-grade" variant (type I) is considered to be a borderline serous tumor / atypical proliferative serous tumor (8442/1), which according to the International Classification of Diseases for Oncology ICD-O 2013 of the female reproductive system refers to non-specific, borderline tumors and tumors with unpredictable clinical behavior. The predecessors of the “high-grade” variant (type II) are serous tubular intraepithelial carcinomas (in situ) or “high-grade” serous invasive tubal carcinomas, since they have the TP53 mutation identical to “high-grade” ovarian carcinoma, an aberrant p53 protein expression, high proliferative activity, and significant genomic instability. In addition, according to the carcinogenesis of "high-grade" serous ovarian carcinoma with metastases to the peritoneum, it can also be interpreted as "pelvic high-grade serous carcinoma". A retrospective analysis of the histological, morphometric and immunohistochemical characteristics of the biopsy material of 31 women aged from 28 to 76 years (mean 57.32±11.54; median 57), divided into 3 groups, was carried out. Group 1: 14 observations of the tubal epithelium (8 tubes without pathological changes (subgroup 1a) and 6 with signs of intraepithelial neoplasia (subgroup 1b); group 2: 12 cases of serous adenocarcinoma of the ovary of the “high-grade” variant; group 3: 6 metastatic peritoneal serous carcinoma without a known primary site. Results. Group immunophenotypes showed uniformity in the expression of markers CK7 (+, +/-), CK20 (-), WT-1 (+), CA125 (+, +/-), with an affinity to distal uterine tube fragments. The expression of p53 in all groups with signs of carcinomas (compared with the control subgroup 1a without atypia) was divided into two options - negative samples and samples with overexpression, where no statistically significant difference was found (p&gt;0.05), which is possibly a single way of carcinogenesis. The morphometric study revealed a significant difference in the area of the nuclei between group 3 and the first three groups (1a, 1b, 2), which indicates the similarity of ovarian and tubal neoplasias and uterine tube epithelium. The number of intranuclear reactions with ER and PGR progressively decreased from group 1 to group 3, with an increase in cases with ER (+/-) / PGR (+/- or -) to 50% in group 3, which greatly complicated the diagnostic search for unknown carcinomas of primary localization. HER-2-new expression revealed a possible amplification (gradation 2 + / 3 +) only in group 2 at the level of 16.67% and in group 3 at the level of 33.33%.

Intratumoral Heterogeneity Accounts for Apparent Progression of Noninvasive Serous Tumors to Invasive Low-grade Serous Carcinoma: A Study of 30 Low-grade Serous Tumors of the Ovary in 18 Patients With Peritoneal Carcinomatosis.

Noninvasive ovarian low-grade serous tumors [atypical proliferative serous tumor (APST)/serous borderline tumor] appear to progress to invasive low-grade serous carcinoma (LGSC) at a low but regular rate. The underlying biology of this phenomenon is unknown. We studied 18 patients with 30 ovarian tumors (12 bilateral), including APST, noninvasive LGSC and invasive LGSC, who also had low-grade serous carcinomatosis. Tumors were evaluated for microinvasion (usual eosinophilic cell type), microinvasive carcinoma (<5 mm invasion of micropapillary nests), and overt carcinoma (≥5 mm invasion of micropapillary nests). Tumors were evaluated based on the original numerical order of sections under the hypothetical scenarios in which sampling was stopped at 1 section/cm and 2 sections/cm. Sampling based on 1 section/cm of greatest tumor dimension identified invasion of any type in 21 tumors (70%). Among these 21 tumors, 10 had microinvasive carcinoma, and 11 overt carcinoma. Sampling based on 2 sections/cm identified microinvasive carcinoma in 9 tumors and overt carcinoma in 14 tumors. With increased sampling from 1 to 2 sections/cm, the diagnosis in 3 tumors would have changed from microinvasive carcinoma to overt carcinoma, and in an additional 2 tumors from APST to APST with microinvasive carcinoma. Sampling based on >2 sections/cm changed the diagnosis in 1 additional case of APST with microinvasive carcinoma to overt carcinoma. These findings support that undetected (unsampled) occult invasion in the primary ovarian tumors is a likely explanation for some cases of apparent progression of noninvasive low-grade serous ovarian tumors to invasive LGSC. To minimize undetected occult invasion, consideration of sampling noninvasive low-grade ovarian serous tumors with at least 2 sections/cm of maximum tumor diameter may be warranted. The eosinophilic cell type of microinvasion, or microinvasive carcinoma, regardless of size, should prompt further sampling to identify overt carcinoma. The eosinophilic type of microinvasion was never seen alone in this cohort and by itself may be biologically insignificant.

Clinicopathologic and Molecular Features of Paired Cases of Metachronous Ovarian Serous Borderline Tumor and Subsequent Serous Carcinoma.

Although risk factors have been established for the development of serous carcinoma after a diagnosis of serous borderline tumor (SBT), comprising atypical proliferative serous tumor (APST) (ie, conventional SBT) and noninvasive low-grade serous carcinoma (niLGSC) (ie, micropapillary SBT), subsequent invasive carcinoma still occurs in a subset of women who are not at increased risk. Whether subsequent serous carcinoma in women with a prior SBT represents malignant progression/recurrence or an independent primary tumor is unclear, and the combined clinicopathologic and molecular features of SBTs and their subsequent carcinomas have not been fully characterized. In this study, we analyzed a cohort of 42 women initially diagnosed with SBT who subsequently developed serous carcinoma of a total of 1025 cases of ovarian SBT from a nationwide population-based cohort. Review of the diagnostic slides was performed from this subset of SBTs and matched metachronous invasive serous carcinomas (39 low grade, 3 high grade). DNA was extracted from tissue blocks available for 41 cases (both SBT and carcinoma, n=36; SBT only, n=3; carcinoma only, n=2). Samples were subjected to digital droplet PCR to analyze mutation hotspots in KRAS (codon 12) and BRAF (V600E), which are frequently found in low-grade serous tumors. Eighty-one percent of SBTs (34/42) were APST, and 19% (8/42) were niLGSC. Forty percent of cases (17/42) were FIGO stage I, the majority of which were APST (14/17; 82%). The median time to development of carcinoma was 9 years (range, 0.6 to 25 y). Mutations in SBTs were distributed as follows: 5/39 (13%) BRAF mutant, 22/39 (56%) KRAS mutant, and 12/39 (31%) wild-type for both genes. There was a significant relationship between SBT gene mutation and histologic type, with BRAF mutations occurring exclusively in APST and a higher frequency of niLGSC among SBTs wild-type for BRAF and KRAS (P=0.01). The diffuse presence of tumor cells with abundant eosinophilic cytoplasm was significantly associated with the BRAF mutation (P=0.001). Mutational analyses of matched SBT/carcinoma pairs revealed concordant profiles in 33/36 (92%) cases, of which 19 (53%) were KRAS mutant, 4 (11%) were BRAF mutant, and 10 (28%) were wild type for both genes. The 3 discordant cases consisted of a wild-type niLGSC with a subsequent BRAF-mutant invasive LGSC, a KRAS-mutant APST with a KRAS-mutant LGSC, and a BRAF-mutant APST with subsequent development of a KRAS-mutant high-grade serous carcinoma. In conclusion, some women with SBTs can subsequently develop serous carcinoma, occasionally over 10 years later. Most subsequent carcinomas are low grade, but a small subset can be high grade. The type of gene mutation in SBT correlates with various histologic features. While most cases of serous carcinoma developing after a diagnosis of SBT probably represent tumor progression, a minority are independent primary tumors, presumably arising from endosalpingiosis.

Comprehensive in situ analysis of ALDH1 and SOX2 reveals increased expression of stem cell markers in high-grade serous carcinomas compared to low-grade serous carcinomas and atypical proliferative serous tumors

Recent studies have shown that re-expression of stem cell factors contribute to pathogenesis, therapy resistance, and recurrent disease in ovarian carcinomas. In this study, we compare the expression and co-expression of stem cell markers ALDH1 and SOX2 in different types of serous ovarian tumors. A total of 215 serous ovarian tumors (161 high-grade serous carcinomas (HGSC), 17 low-grade serous carcinomas (LGSC), 37 atypical proliferative serous tumors (APST)), and 10 cases of serous tubal intraepithelial carcinoma (STIC) were analyzed. Double immunostaining experiments addressed the association of cell proliferation (Ki67) with ALDH1 and the potential co-expression of SOX2 and ALDH1. The prognostic effect was analyzed in the cohort of HGSC. Expression of ALDH1and/or SOX2 was detected with increased frequency in HGSC (88.8%), compared with LGSC (70.5%) and APST (36.4%), while ALDH1 alone was significantly more frequently expressed in LGSC. The majority of all tumor types showed expression of ALDH1 and SOX2 in different cells. Only a minority of HGSC (4.6%) and STIC (20%) showed SOX2/ALDH1 co-expression in > 10% of tumor cells. Double staining also revealed that ALDH1 is associated with the non-proliferating Ki67-negative fraction consistent with a stem cell phenotype. Co-expression of ALDH1 and SOX2 or ALDH1 and Ki67 has no effect on survival. Expression of stem cell factors ALDH1 and/or SOX2 shows increased frequency in high-grade serous ovarian carcinomas compared to low-grade carcinomas and borderline tumors, supporting the concept that stem cell markers play different biological roles in low-grade versus high-grade serous neoplasia of the ovary.

Assessing the landscape of ovarian serous borderline tumors.

To compare distinct clinicopathological features between atypical proliferative serous tumors and non-invasive low-grade ovarian serous carcinomas. Our study group comprised 203 cases of serous borderline tumors sub-classified as atypical proliferative serous tumors or as non-invasive low-grade serous carcinomas. All pathological features related to borderline tumors were re-evaluated by two gynecological pathologists. Data concerning recurrences and survival were retrieved from the medical records of the patients. When comparing atypical proliferative serous tumors to non-invasive low-grade serous carcinomas, the latter were statistically related to advanced stage at diagnosis, bilateral disease, exophytic pattern of growth, microinvasive carcinoma, and the presence of invasive implants. In univariate analysis, recurrences were statistically related to the exophytic pattern of growth, to microinvasion, and to the presence of implants (both invasive and non-invasive). Nevertheless, in multivariate analysis, only microinvasion and the presence of invasive implants were related to recurrence. Women who eventually succumbed to the disease were only those with invasive implants. Their ovarian tumor was either a non-invasive low-grade serous carcinoma or an atypical proliferative serous tumor with 'minimal' micropapillary pattern. Neither lymph node involvement nor endosalpingiosis seemed to influence the course of the disease. The results of our study underline the increased possibility of non-invasive low-grade serous carcinomas to be related with features indicative of aggressive behavior as opposed to atypical proliferative serous tumors. Nevertheless, irrespective of tumor histology, the presence of invasive implants and microinvasion were the only independent prognostications of recurrence.

MiR-223 potentially targets SWI/SNF complex protein SMARCD1 in atypical proliferative serous tumor and high-grade ovarian serous carcinoma

Ovarian cancer is the fifth most common cancer in women worldwide and has the highest mortality amongst gynecological cancers. miRNAs are a class of non-coding RNAs, approximately 22 nt long, that negatively regulate gene expression and have roles in cell growth, differentiation, metabolism, apoptosis and tumorigenesis. Dysregulated miRNA-223 expression has been implicated in a wide range of cancer subtypes. SMARCD1 is an integral protein component of the SWI/SNF complex, which remodels chromatin, and which has important roles in transcriptional control, DNA replication, recombination and repair. In this study, we examined whether the expression levels of miR-223 and SMARCD1 are altered in ovarian serous neoplasia and whether miR-223 functionally regulates the gene and protein expression of SMARCD1 in vivo, as has been predicted by in silico methods. Benign, atypical proliferative serous tumors (borderline) and malignant serous tumors (n = 144) were laser-capture microdissected, and relative expression levels of miR-223 and SMARCD1 were quantified by RT-PCR. Ovarian cancer cell line OC316 was reverse transfected with a miR-223 mimic, and relative expression levels of miR-223 and SMARCD1 were quantified by reverse-transcription polymerase chain reaction; protein expression of SMARCD1 was evaluated by Western blot. miR-223 expression was up-regulated in high-grade ovarian serous carcinoma samples (median RQ = 4.8881, P = .0045), whilst SMARCD1 was down-regulated (median RQ = 0.5107, P = .0492). In OC316 cells transfected with a miR-223 mimic, SMARCD1 gene expression was down-regulated 3-fold (P = .001), and SMARCD1 protein expression was down-regulated 2-fold (P = .002). These results suggest a regulatory role for miR-223 in ovarian serous neoplasia, linking it with SMARCD1.

Mutation of NRAS is a rare genetic event in ovarian low-grade serous carcinoma

Activating mutations involving the members of the RAS signaling pathway, including KRAS, NRAS, and BRAF, have been reported in ovarian low-grade serous carcinoma and its precursor lesion, serous borderline tumor (SBT). Whether additional genetic alterations in the RAS oncogene family accumulate during the progression of SBT to invasive low-grade serous carcinoma (LGSC) remains largely unknown. Although mutations of KRAS and BRAF occur at a very early stage of progression, even preceding the development of SBT, additional driving events, such as NRAS mutations, have been postulated to facilitate progression. In this study, we analyzed NRAS exon 3 mutational status in 98 cases that were diagnosed with SBT/atypical proliferative serous tumor, noninvasive LGSC, or invasive LGSC. Of the latter, NRAS Q61R (CAA to CGA) mutations were detected in only 2 of 56 (3.6%) cases. The same mutation was not detected in any of the SBTs (atypical proliferative serous tumors) or noninvasive LGSCs. Mutational analysis for hotspots in KRAS and BRAF demonstrated a wild-type pattern of KRAS and BRAF in one of the NRAS-mutated cases. Interestingly, another LGSC case with NRAS mutation harbored a concurrent BRAF V600L mutation. These findings indicate that, although recurrent NRAS mutations are present, their low prevalence indicates that NRAS plays a limited role in the development of LGSC. Further studies to identify other oncogenic events that drive LGSC progression are warranted.

Long-term Behavior of Serous Borderline Tumors Subdivided Into Atypical Proliferative Tumors and Noninvasive Low-grade Carcinomas: A Population-based Clinicopathologic Study of 942 Cases.

Ovarian serous borderline tumors (SBTs) have been the subject of considerable controversy, particularly with regard to terminology and behavior. It has been proposed that they constitute a heterogenous group of tumors composed, for the most part, of typical SBTs that are benign and designated "atypical proliferative serous tumor (APST)" and a small subset of SBTs with micropapillary architecture that have a poor outcome and are designated "noninvasive low-grade serous carcinoma (niLGSC)". It also has been argued that the difference in behavior between the 2 groups is not due to the subtype of the primary tumor but rather the presence of extraovarian disease, specifically invasive implants. According to the terminology of the 2014 WHO Classification, typical SBTs are equivalent to APSTs and SBTs displaying micropapillary architecture are synonymous with niLGSC. In addition, "invasive implants" were renamed "low-grade serous carcinoma" (LGSC). The argument as to whether it is the appearance of the primary tumor or the presence of extraovarian LGSC that determines outcome remains unsettled. The current study was initiated in 2004 and was designed to determine what factors were predictive of outcome, with special attention to the appearance of the primary tumor (APST vs. niLGSC) and that of the extraovarian disease (noninvasive vs. invasive implants). Our study is population based, involving the entire female population of Denmark. None of the women in the study were lost to follow-up, which ranged up to 36 years (median, 15 y). All the microscopic slides from the contributing hospitals were rereviewed by a panel of 2 pathologists (R.V. and R.J.K.) who were blinded to the follow-up. After excluding those that were not SBTs by the pathology panel, as well as cases with a prior or concurrent cancer or undefined stage, 942 women remained, of which 867 were APSTs and 75 were niLGSCs. The median patient age was 50 years (range, 16 to 97 y). Eight hundred nine women (86%) presented with FIGO stage I disease, whereas 133 (14%) had advanced stage disease. Compared with APSTs, niLGSC exhibited a significantly greater frequency of bilaterality, residual gross disease after surgery, microinvasion/microinvasive carcinoma, advanced stage disease, and invasive implants at presentation (P-values <0.003). Because the cause of death is difficult to accurately ascertain from death certificates, we used development of invasive serous carcinoma as the primary endpoint as following development of carcinoma, the mortality is very high. In the entire cohort, subsequent development of carcinoma occurred in 4%, of which 93% were low grade and 7% high grade (median time, 10 y; range, up to 25 y). After adjusting for age at and time since diagnosis of APST or niLGSC, occurrence of subsequent carcinoma was significantly higher with niLGSC than APST among all stages combined (hazard ratio [HR]=3.8; 95% confidence interval [CI], 1.7-8.2). This difference was still significant for stage I but not advanced stage cases. Moreover, all-cause mortality was not statistically significantly different between APST and niLGSC. Of all women with advanced stage disease, 114 (86%) had noninvasive implants, whereas 19 (14%) were invasive. Noninvasive implants were significantly associated with subsequent development of carcinoma (HR=7.7; 95% CI, 3.9-15.0), but the risk with invasive implants was significantly higher (HR=42.3; 95% CI, 16.1-111.1). In conclusion, although invasive implants are the most important feature in predicting an adverse outcome, subclassification into APST and niLGSC is important as it stratifies women with respect to risk for advanced stage disease and invasive implants for all women and development of serous carcinoma for stage I cases.

A nationwide study of ovarian serous borderline tumors in Denmark 1978–2002. Risk of recurrence, and development of ovarian serous carcinoma

ObjectiveAbsolute risk and risk factors for recurrence and ovarian serous carcinoma following ovarian serous borderline tumors (SBTs) is not well-established. MethodsWe included all women with SBTs in Denmark, 1978–2002. Diagnoses were confirmed by centralized pathology review and classified as atypical proliferative serous tumor (APST) or noninvasive low-grade serous carcinoma (LGSC). Implants were classified as noninvasive or invasive. Medical records were collected and reviewed, and follow-up was obtained. Subsequent diagnoses were also confirmed by centralized pathology review. We examined absolute risk and risk factors for recurrent APST and serous carcinoma using Cox regression. ResultsThe absolute serous carcinoma risk after, respectively, 5 and 20years was 5.0% and 13.9% for noninvasive LGSC, and 0.9% and 3.7% for APST. Serous carcinoma risk was significantly higher following noninvasive LGSC compared with APST among stage I patients/patients without implants (HR=5.3; 95% CI: 1.7–16.3), whereas no significant association with tumor type was found in advanced stage patients/patients with implants. Advanced stage – notably invasive implants – bilaterality, surface involvement, and residual disease increased serous carcinoma risk. However, women with stage I APST also had a higher risk than the general population. ConclusionsThis largest population-based cohort of verified SBTs revealed that women with noninvasive LGSC are significantly more likely to develop serous carcinoma than women with APST, which could not entirely be explained by invasive implants. Although invasive implants was a strong risk factor for serous carcinoma, even women with stage I APST were at increased risk compared with the general population.

Epithelial Malignancies Arising in Ovarian Mature Cystic Teratoma: A Series, of 26 Cases

Objective: To report a series of epithelial malignancies arising within ovarian teratomas along with clinical followup. Some previously unreported combinations of malignant component with MCT are also being reported. Material and Methods: Clinico-pathological details and clinical follow up of twenty six cases reported during January 2000 to March 2014 in the Section of Histopathology, of a tertiary care hospital of Pakistan are included. Results: Total 1418 cases of MCTs were reported, 26 (1.8%) of them showed epithelial malignancies. The mean age at presentation was 42.5 years (range; 15-70 years). Commonest clinical presentation was with abdominal pain and mass. All the patients underwent surgery as first line treatment. Malignant transformation in form of Squamous cell carcinoma was seen in 20 cases. In one case, in addition to squamous cell carcinoma, atypical proliferative serous tumor and high grade sarcomatous component was also present. Adenosquamous carcinoma, Poorly differentiated carcinoma, Endometrioid adenocarcinoma and Adenocarcinoma with mucinous differentiation represented malignant components in additional 4 cases respectively. Cases demonstrating endometrioid features and atypical proliferative serous tumor represent collision tumors. Two of the cases had papillary carcinoma (follicular variant) of thyroid arising within monodermal teratoma (struma ovarii). Clinical follow up was available in 13 cases and it is noted that patients with squamous cell carcinoma had a worse outcome. Conclusions: Malignancy occurring in a MCT is an extremely rare occurrence. It is very challenging to diagnose this malignant transformation clinically.

Molecular Alterations of TP53 are a Defining Feature of Ovarian High-Grade Serous Carcinoma: A Rereview of Cases Lacking TP53 Mutations in The Cancer Genome Atlas Ovarian Study.

The Cancer Genome Atlas has reported that 96% of ovarian high-grade serous carcinomas (HGSCs) have TP53 somatic mutations suggesting that mutation of this gene is a defining feature of this neoplasm. In the current study, 5 gynecologic pathologists independently evaluated hematoxylin and eosin slides of 14 available cases from The Cancer Genome Atlas classified as HGSC that lacked a TP53 mutation. The histologic diagnoses rendered by these pathologists and the accompanying molecular genetic data are the subject of this report. Only 1 case (Case 5), which contained a homozygous deletion of TP53, had unanimous interobserver agreement for a diagnosis of pure HGSC. In 1 case (Case 3), all 5 observers (100%) rendered a diagnosis of HGSC; however, 3 observers (60%) noted that the histologic features were not classic for HGSC and suggested this case may have arisen from a low-grade serous carcinoma (arisen from an alternate pathway compared with the usual HGSC). In 2 cases (Cases 4 and 12), only 3 observers (60%) in each case, respectively, interpreted it as having a component of HGSC. In the remaining 10 (71%) of tumors (Cases 1, 2, 6-11, 13, and 14), the consensus diagnosis was not HGSC, with individual diagnoses including low-grade serous carcinoma, high-grade endometrioid carcinoma, HGSC, metastatic carcinoma, clear cell carcinoma, atypical proliferative (borderline) serous tumor, and adenocarcinoma, not otherwise specified. Therefore, 13 (93%) of the tumors (Cases 1-4 and 6-14) were either not a pure HGSC or represented a diagnosis other than HGSC, all with molecular results not characteristic of HGSC. Accordingly, our review of the TP53 wild-type HGSCs reported in The Cancer Genome Atlas suggests that 100% of de novo HGSCs contain TP53 somatic mutations or deletions, with the exception of the rare HGSCs that develop from a low-grade serous tumor precursor. We, therefore, propose that lack of molecular alterations of TP53 are essentially inconsistent with the diagnosis of ovarian HGSC and that tumors diagnosed as such should be rigorously reassessed to achieve correct classification.

BRAF mutation is associated with a specific cell type with features suggestive of senescence in ovarian serous borderline (atypical proliferative) tumors.

Serous borderline tumor also known as atypical proliferative serous tumor (APST) is the precursor of ovarian low-grade serous carcinoma (LGSC). In this study, we correlated the morphologic and immunohistochemical phenotypes of 71 APSTs and 18 LGSCs with the mutational status of KRAS and BRAF, the most common molecular genetic changes in these neoplasms. A subset of cells characterized by abundant eosinophilic cytoplasm (EC), discrete cell borders, and bland nuclei was identified in all (100%) 25 BRAF-mutated APSTs but in only 5 (10%) of 46 APSTs without BRAF mutations (P<0.0001). Among the 18 LGSCs, EC cells were found in only 2, and both contained BRAF mutations. The EC cells were present admixed with cuboidal and columnar cells lining the papillae and appeared to be budding from the surface, resulting in individual cells and clusters of detached cells "floating" above the papillae. Immunohistochemistry showed that the EC cells always expressed p16, a senescence-associated marker, and had a significantly lower Ki-67 labeling index than adjacent cuboidal and columnar cells (P=0.02). In vitro studies supported the interpretation that these cells were undergoing senescence, as the same morphologic features could be reproduced in cultured epithelial cells by ectopic expression of BRAF(V600E). Senescence was further established by markers such as SA-β-gal staining, expression of p16 and p21, and reduction in DNA synthesis. In conclusion, this study sheds light on the pathogenesis of this unique group of ovarian tumors by showing that BRAF mutation is associated with cellular senescence and the presence of a specific cell type characterized by abundant EC. This "oncogene-induced senescence" phenotype may represent a mechanism that impedes progression of APSTs to LGSC.

Papillary Tubal Hyperplasia

In contrast to the controversy regarding the terminology and behavior of ovarian noninvasive low-grade serous tumors [atypical proliferative serous tumor (APST) and serous borderline tumor], little attention has been directed to their origin. Similarly, until recently, proliferative lesions in the fallopian tube had not been extensively studied. The recent proposal that ovarian high-grade serous carcinomas are derived from intraepithelial carcinoma in the fallopian tube prompted us to evaluate the possible role of fallopian tube in the genesis of low-grade serous tumors. We have identified a lesion, designated "papillary tubal hyperplasia (PTH)," characterized by small rounded clusters of tubal epithelial cells and small papillae, with or without associated psammoma bodies, that are present within the tubal lumen and which are frequently associated with APSTs. Twenty-two cases in this study were selected from a population-based study in Denmark of approximately 1000 patients with low-grade ovarian serous tumors in whom implants were identified on the fallopian tube. Seven additional cases were seen recently in consultation at The Johns Hopkins Hospital (JHH). These 7 cases were not associated with an ovarian tumor. PTH was found in 20 (91%) of the 22 cases in the Danish study. On the basis of this association of PTH with APSTs with implants and the close morphologic resemblance of PTH, not only to primary ovarian APSTs but also to noninvasive epithelial implants and endosalpingiosis, we speculate that the small papillae and clusters of cells from the fallopian tube implant on ovarian and peritoneal surfaces to produce these lesions. The 7 JHH cases of PTH that were not associated with an ovarian tumor support the view that PTH is the likely precursor lesion. We propose a model for the development of ovarian and extraovarian low-grade serous proliferations (APST, noninvasive epithelial implants, and endosalpingiosis) that postulates that all of these lesions are derived from PTH, which appears to be induced by chronic inflammation. If this hypothesis is confirmed, it can be concluded that low-grade and high-grade ovarian tumors develop from tubal epithelium and involve the ovary secondarily.

Metaplastic Papillary Tumor of the Salpinx

Metaplastic papillary tumor (MPT) of the salpinx is a rare lesion found in the lumen of fallopian tubes during the postpartum period. This lesion is very small and is composed microscopically of papillae lined by stratified epithelium. Similar to serous borderline ovarian tumors (BOTs), epithelial elements of MPT show a budding, abundant, dense, and eosinophilic cytoplasm, bland nuclei or with mild atypia. It is not clear whether this lesion is a papillary metaplastic proliferation or a small atypical proliferative (borderline) serous tumor associated with pregnancy. Owing to its rarity, MPT has never been investigated in molecular studies and compared with ovarian serous neoplasms. In this study, a case of tubal MPT was molecularly examined and compared with 4 BOTs and with 2 low-grade ovarian carcinomas, using microsatellite analysis with 13 markers at 8 chromosomal regions involved in ovarian carcinogenesis. The tubal MPT and one of the BOTs showed no alterations in the investigated chromosomal regions. The remaining 3 BOTs showed only single allelic imbalances. Instead, low-grade serous carcinomas showed a higher frequency of alterations, including allelic imbalance at chr10q23, 1p36, 9p22, and 17. In conclusion, this study provides, for the first time, molecular data on an MPT of the fallopian tube, indicating that this entity might share both morphologic and molecular similarities with a subset of minimally altered BOTs, termed atypical proliferative serous tumors, which behave in a benign manner. However, in our opinion, further molecular studies should be conducted on other cases of MPTs to confirm this hypothesis.

The Relationship Between Papillary Infarction and Microinvasion in Ovarian Atypical Proliferative (“Borderline”) Serous and Seromucinous Tumors

Papillary infarction is commonly observed in ovarian atypical proliferative serous and seromucinous tumors (APST/APSMT), but there are no published data on its significance. This study characterizes the features associated with papillary infarcts and microinvasion to further understand these phenomena. From consecutive hospital-based cases, 32 APST/APSMT in 26 patients (6 bilateral) were reviewed and evaluated for papillary infarcts, microinvasion (<5 mm), and other histologic features. Among the tumors, 69% were APSTs and 31% APSMTs. Infarcts were identified in 46% of patients, and microinvasion in 27%. Microinvasion was significantly more common in tumors with infarcts (50%) than in those without (7%; P=0.0261). Papillary infarcts were significantly more common in APSTs (61%) than in APSMTs (13%; P=0.0357). The microinvasive tumors were significantly more likely to be bilateral (57% vs. 11%, P=0.0278). The mean infarct size in the presence of microinvasion was 5.9 mm, and in the absence of microinvasion, 2.2 mm (not significant). The infarcts were topographically separate from the foci of microinvasion. Other features evaluated showed no meaningful correlations with microinvasion or infarction. Proliferative noninvasive serous tumors with papillary infarcts are significantly more likely to have microinvasion, and papillary infarcts are more common in APSTs than in APSMTs. APSTs with microinvasion are more common than earlier appreciated. Whether papillary infarction is pathogenetically related to microinvasion is unknown and warrants further investigation.

Low-grade Serous Carcinoma of the Ovary Displaying a Macropapillary Pattern of Invasion

Invasive micropapillary serous carcinoma (MPSC) also designated "low-grade serous carcinoma" (LGSC) of the ovary is characterized by small micropapillae that infiltrate underlying tissue (ovarian stroma). On occasion these tumors in addition to the micropapillae contain large macropapillae lined by bland epithelium. In rare cases, the entire tumor is composed of macropapillae. In these cases, the question of whether this is an invasive carcinoma or an unusual type of adenofibroma has been raised. The goal of this study was to describe this unusual macropapillary pattern of invasion in LGSC. Cases of LGSC containing macropapillae were retrieved from the files of the Johns Hopkins Hospital. In addition to a detailed morphologic analysis, the mutational status of KRAS and BRAF in the macropapillary, noninvasive, and invasive MPSC components was analyzed by nucleotide sequencing. There were 14 cases containing macropapillae (11 cases of LGSC, 2 cases of atypical proliferative serous tumor (APST) with microinvasion, and 1 case of APST with a focus of LGSC with macropapillae in perivaginal soft tissue). In 3 cases, extraovarian metastases contained macropapillae. Molecular analysis of the primary tumor components (macropapillary, noninvasive, and invasive MPSC and/or APST) was performed in 7 cases and of a lymph node metastasis with macropapillae in 1 case. The identical KRAS mutation was detected in all of the analyzed components of the primary ovarian tumors in 4 cases. In one of these cases, macropapillae in the lymph node metastasis contained a KRAS mutation identical to the primary tumor. The BRAF mutation identified in 1 case was identical in all components of the ovarian tumor. The identical mutations in the macropapillae and the other tumor components in each case indicate that they are clonally related. The finding of macropapillae within lymph nodes supports the interpretation that the macropapillary component is another manifestation of invasion in LGSC. The recognition of this pattern is important, especially in cases when a tumor is composed entirely of macropapillae.

The Development of High-grade Serous Carcinoma From Atypical Proliferative (Borderline) Serous Tumors and Low-grade Micropapillary Serous Carcinoma

Recently, we have proposed a model for the development of ovarian surface epithelial tumors. In this model, all histologic types of surface epithelial tumors are divided into 2 categories designated type I and type II which correspond to 2 pathways of tumorigenesis. Type I tumors include low-grade serous carcinoma, mucinous carcinoma, endometrioid carcinoma, malignant Brenner tumor, and clear cell carcinoma which develop slowly in a stepwise fashion from well-recognized precursors, namely atypical proliferative (borderline) tumors. Type II tumors are high-grade, rapidly growing tumors that typically have spread beyond the ovaries at presentation. They include high-grade serous carcinoma ("moderately" and "poorly" differentiated), malignant mixed mesodermal tumors (carcinosarcomas), and undifferentiated carcinoma. These tumors are rarely associated with morphologically recognizable precursor lesions and it has been proposed that they develop "de novo" from ovarian inclusion cysts. This model implies that the pathogenesis of type I and type II tumors are separate and independent but it is not clear whether some type II tumors develop from type I tumors. In this study, we attempted to address this issue by determining the clonality of 6 cases of high-grade serous carcinomas that were closely associated with atypical proliferative serous (borderline) tumors and invasive low-grade micropapillary serous carcinomas. We reviewed 210 ovarian serous tumors from the surgical pathology files of the Johns Hopkins Hospital and identified 3 high-grade serous carcinoma that were directly associated with atypical proliferative serous (borderline) tumors and 3 that were associated with invasive low-grade micropapillary serous carcinomas. A morphologic continuum between the high-grade carcinoma and the low-grade tumors was observed in 4 cases whereas in the remaining 2 cases the high-grade and low-grade components were separate. Mutational analyses for KRAS, BRAF, and p53 genes were performed on microdissected samples from the high-grade and low-grade tumor areas for each case. All 6 tumors demonstrated wild-type BRAF and p53 genes. Only 2 of the 6 cases were informative from a molecular genetic standpoint. In those 2 cases we found the same mutations of KRAS in both the atypical proliferative serous (borderline) tumor and the high-grade serous carcinoma component of the tumor, indicating a clonal relationship. The above results suggest that the majority of high-grade and low-grade carcinomas develop independently but in rare cases, a high-grade serous carcinoma may arise from an atypical proliferative serous (borderline) tumor.

Patterns of p53 Mutations Separate Ovarian Serous Borderline Tumors and Low- and High-grade Carcinomas and Provide Support for a New Model of Ovarian Carcinogenesis

The infrequent association of serous borderline tumors (SBTs) with invasive serous carcinoma has led to the view that SBTs are unrelated to invasive serous carcinoma. Nonetheless, mortality associated with SBTs is generally attributed to malignant transformation, and traditionally these tumors have been designated as "carcinomas of low malignant potential." Previous immunohistochemical studies evaluating p53 expression and molecular genetic studies evaluating mutational status have reported that p53 overexpression and mutations are infrequent in SBTs and occur in as many as 50% to 80% of invasive serous carcinomas. The different methodologies for determining p53 status and the failure to correlate the findings with tumor grade make these studies difficult to interpret. The current study was undertaken to overcome these deficiencies and to reconcile the relationship of SBTs to invasive serous carcinoma by performing a morphologic, immunohistochemical, and molecular genetic analysis comparing SBTs with low- and high-grade serous carcinoma. The molecular genetic analysis used a highly stringent, carefully designed nucleotide-sequencing method. A total of 96 sporadic serous tumors including 25 SBTs (11 atypical proliferative serous tumors and 14 intraepithelial low-grade serous carcinomas [noninvasive micropapillary serous carcinomas, MPSCs]), 12 low-grade serous carcinomas (invasive MPSCs), and 59 high-grade serous carcinomas were analyzed for their p53 mutational status of exons 5 to 9. Functional mutations, defined as mutations resulting in the alteration of the structure of the encoded protein, were detected in 30 of 59 (50.8%) high-grade serous carcinomas and 1 (8.3%) of 12 low-grade invasive serous carcinomas compared with 2 (8%) of 25 SBTs, both of these in intraepithelial low-grade serous carcinomas (noninvasive MPSCs). The similar frequency of p53 mutations in SBTs and low-grade invasive serous carcinomas in contrast to the significantly higher frequency of p53 mutations in high-grade serous carcinomas (P < 0.0005) suggests a common lineage for SBTs and low-grade invasive serous carcinomas and supports the view that SBTs are unrelated to the usual type of invasive serous carcinoma, which is a high-grade neoplasm. Mutational status was also correlated with p53 immunoreactivity. Although p53 immunoreactivity is generally higher in those specimens containing mutant p53, immunostaining is neither sufficiently specific nor sensitive enough to predict p53 mutations. The molecular genetic findings confirm our hypothesis of dual pathways of serous carcinogenesis based on previous analyses of KRAS and BRAF mutations on the same set of cases in which KRAS and BRAF mutations were found in 60% of SBTs and low-grade serous carcinoma but not in high-grade serous carcinomas. Based on these studies, we have proposed a model of serous carcinogenesis in which SBTs are the precursors of low-grade serous carcinomas whereas the usual type of invasive serous carcinoma is a high-grade neoplasm that develops "de novo" from in situ alterations in epithelial inclusion cysts.

Noninvasive and invasive micropapillary (low-grade) serous carcinoma of the ovary: a clinicopathologic analysis of 135 cases.

Reports describing the behavior of micropapillary serous carcinomas (MPSCs) of the ovary have focused on those that are noninvasive. There are only very limited data on the behavior of those that are invasive. To further characterize the behavior of MPSCs, invasive versus noninvasive primary tumors were distinguished based on the presence or absence of destructive infiltrative growth. To qualify for inclusion, invasive MPSCs, like the noninvasive tumors, were required to display a micropapillary architecture and low-grade nuclei. A total of 135 cases of MPSC were identified: 96 noninvasive and 39 invasive. On follow-up, survival for 10 patients with stage I noninvasive and invasive MPSCs was 100%, and survival for women with stage II and III noninvasive and invasive MPSCs with noninvasive implants was 80%. In contrast, the 5-year and 10-year survival for patients with stage II and III noninvasive MPSCs with invasive implants was 85% and 55%, respectively. The 5-year and 10-year survival for women with invasive MPSCs and invasive implants was 55% and 45%, respectively. The median time from diagnosis to death for women with noninvasive and invasive MPSCs with invasive implants was 60 months (range 33-240 months). The indolent behavior of these low-grade carcinomas distinguishes them from conventional serous carcinomas, which are high-grade aggressive neoplasms. Five of six patients with small (<5 mm) MPSCs in whom follow-up was available presented with high stage disease. Of these five women, three are alive and well and two are alive with disease (one with invasive and one with noninvasive implants). Nearly three fourths of noninvasive MPSCs were associated with atypical proliferative serous tumors, adenofibromas, or both, and 62% of invasive MPSCs were associated with noninvasive MPSCs, atypical proliferative serous tumors, and adenofibromas, alone or in combination. In addition to the frequent mixtures of these tumor components, transitions between them were common. These data in conjunction with recent molecular genetic studies strongly suggest that MPSCs (low-grade carcinomas) arise from atypical proliferative serous tumors unlike conventional serous carcinomas (high-grade carcinomas), which appear to develop de novo. The findings provide further support for the hypothesis that there are distinct pathways of carcinogenesis for low-grade and high-grade serous carcinoma of the ovary.