Severe Atypia Research Articles

Early Genetic Divergence of High-Grade Carcinomas Originating from Low-Grade Serous Ovarian Neoplasms

The current paradigm implicates a fallopian tube precursor as the origin of most ovarian high-grade serous carcinomas (HGSCs). However, a rare subset of HGSCs develop via a distinct pathway from low-grade serous ovarian neoplasms (namely, serous borderline tumors and low-grade serous carcinoma). This alternate pathway for the development of HGSC and other poorly differentiated carcinomas of the ovary is not well understood. To elucidate the molecular pathogenesis and evolutionary trajectory of histologic transformation of low-grade serous neoplasms, we performed whole exome sequencing on microdissected low-grade and higher-grade components from 7 cases of serous borderline tumor or low-grade serous carcinoma associated with a synchronous or metachronous indeterminate/high-grade carcinoma. In most cases, there were relatively few somatic mutations shared between matched low-grade and higher-grade tumors compared with private mutations specific to each component (ie, phylogenetic trees with short trunks and long branches). Truncal mutations, present across all tumor samples from a given patient, included known drivers of low-grade serous neoplasms: KRAS (G12D, n = 4), BRAF (G469A, n = 1), NF2 (n = 1), and USP9X (n = 1). Transformation to HGSC was associated with a TP53 mutation with bi-allelic inactivation in 3 cases, all with severe nuclear atypia, and associated with genome-wide copy number alterations and allelic imbalances. TP53-wildtype tumors comprised a morphologic spectrum, which included indeterminate-grade serous carcinomas with moderate nuclear atypia and high mitotic activity, although lacking extensive chromosomal instability (n = 2) and poorly differentiated carcinomas (n = 2, including a high-grade Mullerian carcinoma and an undifferentiated carcinoma with sarcomatoid features). In summary, synchronous and metachronous low-grade serous neoplasms and higher-grade carcinomas are clonally related. Early genetic divergence, most evident in cases with TP53 mutations, suggests that high-grade transformation may be a relatively early molecular event.

BRCA1-associated-protein-1 inactivated melanocytic tumours: characterisation of the clinicopathological spectrum and immunohistochemical expression pattern of preferentially expressed antigen in melanoma.

BRCA1-associaed protein-1 (BAP1) inactivated tumours (BIMT) are rare melanocytic tumours that may be mistaken for Spitz tumours or melanoma. They occur sporadically or in association with the BAP1 tumour predisposition syndrome (BAP1-TPDS), which may be complicated by uveal or cutaneous melanoma, mesothelioma, basal cell carcinoma and renal cell carcinoma. The aim of this study was to characterise the clinicopathological features and the immunohistochemical expression pattern of preferentially expressed antigen in melanoma (PRAME) of BIMT in a large patient cohort. Ethical approval was obtained, haematoxylin and eosin-stained slides were reviewed, PRAME immunohistochemistry was performed and clinical follow-up was obtained from patient records. Sixty-five BIMT from 38 patients (F:M = 4.4:1) were identified. BIMT were typically located on the trunk and head and neck (median size = 0.5 cm). Seven patients with BAP1-TPDS (range = 16-66 years, median = 25) had multiple BIMT (median = 5), while sporadic BIMT were solitary (median patient age = 39 years). One of seven patients with BAP1-TPDS developed additional malignancies (mesothelioma and cutaneous spindle cell melanoma) and died of complications of mesothelioma. All other patients are alive without recurrence of BIMT (median follow-up = 42 months). BIMT presented as intradermal, nodular aggregates of epithelioid melanocytes with low mitotic activity and moderate to severe cytological atypia in 63% of cases. A background conventional naevus was present in 64%. PRAME immunohistochemistry showed negative or weakly patchy positive staining in all BIMT. BIMT are more common in a sporadic setting and behave indolently, despite worrying cytological atypia. PRAME immunohistochemistry is a reassuring tool in distinguishing BIMT from melanoma.

MPATH-Dx Version 2.0 Schema for Melanocytic Lesions: A Robust Tool for Standardized Diagnostic Reporting

The new revised MPATH-Dx (Version 2.0) reporting schema for melanocytic lesions is presented herein. Principal changes include the simplification of the previous five-class Version 1.0 to a four-class hierarchy of melanocytic lesions to improve diagnostic agreement and to provide more explicit guidance in the management of patients. Version 2.0 also has clearly defined histopathological criteria for classification of Class I and II lesions now designated as low-grade (mild to moderate) atypia and high-grade (high-end moderate to severe) atypia, respectively. This new revised schema, also includes specific provisions for the less common WHO pathways to melanoma, provides guidance for classifying "intermediate" Class II tumors (melanocytomas), and recognizes a subset of pT1a melanomas with very low risk and possible eventual reclassification as a neoplasm falling short of fully-evolved melanoma.

Trajectories of illness uncertainty among parents of children with atypical genital appearance due to differences of sex development.

The present study aimed to identify distinct trajectories of parental illness uncertainty among parents of children born with atypical genital appearance due to a difference of sex development over the first year following diagnosis. It was hypothesized that four trajectory classes would emerge, including "low stable," "high stable," "decreasing," and "increasing" classes, and that select demographic, familial, and medical factors would predict these classes. Participants included 56 mothers and 43 fathers of 57 children born with moderate to severe genital atypia. Participants were recruited from eleven specialty clinics across the U.S. Growth mixture modeling (GMM) approaches, controlling for parent dyad clustering, were conducted to examine classes of parental illness uncertainty ratings over time. A three-class GMM was identified as the best-fitting model. The three classes were interpreted as "moderate stable" (56.8%), "low stable" (33.0%), and "declining" (10.3%). Findings suggest possible diagnostic differences across trajectories. Findings highlight the nature of parents' perceptions of ambiguity and uncertainty about their child's diagnosis and treatment the year following their child's birth/diagnosis. Future research is needed to better understand how these trajectories might shift over the course of the child's development. Results support the development of tailored, evidence-based interventions to address coping with uncertainty among families raising a child with chronic health needs.

Clinicopathologically Defined Nevus Subtypes and Melanoma Risk

Early detection of melanoma is a major determinant in disease outcome and drives the number of (over)excised nevi in clinical practice. This study aimed to evaluate demographic features and melanoma risk of clinically suspicious, mainly flat nevus subtypes. Based on the methodology of exvivo dermoscopy and derm dotting, the 12 most prevalent nevus subtypes were identified in a collection of over 7000 nevi excised for medical reasons. Dermoscopical, histopathological and clinical features of these subtypes were described. In addition, the association with melanoma history, histopathological atypia and melanoma occurrence within nevi was compared. Nearly half of the nevi removed for medical reasons were of the hypermelanotic subtype with no or mild histopathological atypia and low melanoma association, suggesting overtreatment in daily practice. Contrarily, the subtypes atypical lentiginous nevus and orange pulverocytic flat nevus were associated with higher proportions of (severe) atypia and melanoma (history). We believe these subtypes may reflect different tumoral and/or (germline) genetic entities with different melanoma risk. The data from this study may direct further prospective research on specific nevus subtypes in order to obtain better insights in associated clinical/genetic factors and melanoma risk.

Monomorphic T-cell post-transplant lymphoproliferative disorder with features of HHV8-negative primary effusion lymphoma: an autopsy case and review of the literature

A 67-year-old man underwent renal transplantation in his twenties. He developed refractory pleural effusion, with many large lymphocytes with severe atypia and mitosis in the effusion, indicating malignant lymphoma. He finally died of respiratory failure. An autopsy revealed atypical lymphocytes positive for CD3, CD4, and CD30 and negative for CD8, CD20, PAX5, human herpesvirus (HHV) 8, and Epstein–Barr virus-encoded small RNAs by immunohistochemistry and in situ hybridization. Atypical lymphocytes also had T-cell receptor gene rearrangements Jβ2, Jγ2, and Jδ1 and chromosomal aberrations der(8)t(1;8)(q21;p21), add(13)(q12), add(14)(q32), and add(16)(q12-13). A few atypical lymphocytes were present at other sites. We finally diagnosed this case as monomorphic T-cell post-transplant lymphoproliferative disorder with features of HHV8-negative primary effusion lymphoma. A literature review only identified six cases (four HHV8-negative, two HHV8-positive) of effusion lymphoma of T-cell type, including the present case. Interestingly, about half of HHV8-negative and HHV8-positive cases had a history of renal transplantation in their twenties. All cases showed tumor CD30 expression, whereas CD4 and CD8 expressions were inconsistent. These findings indicated that this lymphoma may be associated with post-transplant lymphoproliferative disorder by renal transplantation at a young age, although further cases need to be analyzed.

Uterine smooth muscle tumors of uncertain malignant potential: a retrospective evaluation of clinical pathology and immunohistochemistry features

BackgroundUterine smooth muscle tumor of uncertain malignant potential (STUMP) is a group of uterine smooth muscle tumors which cannot be classified as a subtype of leiomyoma or leiomyosarcoma. Diagnosis, prognosis, and treatment of these tumors are challenging due to recurrence, potential of malignancy, and metastasis.MethodsA retrospective cohort study was conducted in southern Iran during 2011 to 2020. We included records of 21 patients with STUMP and 24 patients with leiomyoma by simple randomized sampling in the tertiary health care centers in Shiraz, southern Iran. Slides were reviewed by an expert pathologist for examining mitosis, necrosis, and atypia, and also proper blocks were selected for immunohistochemistry (IHC) staining.ResultsFrom 45 participants, 21 (46.7%) and 24 (53.3%) patients were in the STUMP and normal leiomyoma groups, respectively. Odds ratio and 95% confidence interval (OR (95% C.I)) of pathologic size in the range of 5–10 cm was significantly higher in the STUMP group compared with normal leiomyoma. (CI: 7.22 (1.44–36.22)). Additionally, hyaline necrosis 0.05 (0.0-0.91), mild to moderate atypia 0.02 (0.0-0.4), moderate to severe atypia 0.01 (0.0-0.22), focal atypia 0.01 (0-0.26) and diffuse atypia 0.01 (0-0.26) were significantly fewer in normal leiomyoma compared to the STUMP group. Negative P16 0.01 (0.0007-0.24) and negative Bcl2 0.22 (0.06–0.81) were significantly higher in the normal leiomyoma group compared with the STUMP group. The cut-off points for predicting STUMP were 2.5% (sensitivity = 62% and specificity = 100%) and 45% (sensitivity = 43% and specificity = 96%) for P16 and bcl2, respectively.ConclusionThe category and management of STUMP continues to progress. The diagnosis for STUMP mainly depends on the histopathological manifestations. No single IHC marker such as P53, P16, and Bcl-2 has proved robust enough in separating STUMP from other leiomyoma variants; however, according to our study, we suggest combination use of P16 and Bcl-2 (cut off 2.5 and 45%, respectively) to distinguish equivocal cases of STUMP.

Outcomes of one-stage feminizing genitoplasty in children with congenital adrenal hyperplasia and severe virilization

PurposeTo present our surgical experience and outcomes in congenital adrenal hyperplasia (CAH) patients with severe virilization using a combined technique of total urogenital mobilization (TUM) and a modified pull-through vaginoplasty to perform a safe and effective one-stage feminizing genital reconstruction for these children.MethodsFourteen CAH patients with severe virilization, defined by a Prader IV and V rating of the external genitalia, underwent TUM followed by a limited vaginal pull-through procedure from June 2016 to December 2020. Postoperative anatomical and cosmetic outcomes, and urinary continence, were evaluated.ResultsOut of the 14 cases in this study, 8 were classified as prader IV and 6 as Prader V. The median age at surgery was 11 months (range 6–36 months), and the mean urethral length was 1.4 cm (range 1.2–1.8 cm). The median follow-up period was 4 years. Our cosmetic outcomes were good in 11 (78.5%), satisfactory in 2, and poor in one case. All patients achieved age-appropriate toilet training without urinary incontinence.ConclusionAdopting our surgical approach of TUM with modified pull-through vaginoplasty has simplified feminizing surgical reconstruction in CAH cases with severe genital atypia and a very high vaginal confluence with short urethral length, yielding adequate introitus with good anatomical and cosmetic appearance and adequate urinary continence outcomes.

MANAGEMENT OF CONJUNCTIVAL MELANOMA ARISING FROM PRIMARY ACQUIRED MELANOMA (PAM) : A CASE REPORT

Introduction : Conjunctival melanoma (CMM) is a rare but potentially a life threatening ocular malignancy. It is an aggressive pigmented tumor and the recurrence rate may be as high as 51% over 10 years.1,2 Surgical wide local excision of the tumour and cryotherapy are current standard treatment of CMM.3,4 The purpose of this case is to report our successful management of conjunctival melanoma using wide excision and cryotherapy.
 Case Illustration : A 67-year-old man who presented to our hospital with a large, pigmented lesion arising from inferior and superior fornix conjunctiva in his left eye since 6 months ago. On examination, a massive pigmented tumor sized 25 x 10 x 15 mm, protruding from inferior fornix conjunctiva and sized 7 x 5x 3 mm arising from superior fornix conjunctiva of left eye. The mass was excised with 3 mm free margin from the tumour border confirmed with negative frozen section and followed by cryotherapy and conjunctival reconstruction using oral mucous graft. Histopathology confirmed with invasive conjunctival melanoma arising in PAM with severe atypia and no lymphovascular and perineural metastasis
 Discussion : Two months after we performed wide excision, cryotherapy and oral mucous graft, no recurrence and conjunctival necrosis at primary site were reported.
 Conclusion : A local wide excision with ‘no touch technique’, cryotherapy and oral mucous graft confirmed with negative frozen section are the mainstay treatment of CMM and has achieved satisfying functional outcomes. Since the high recurrence rate of CMM, we have to close follow up for the next 3 years

Clinical, Morphologic, and Molecular Features of MAP3K8 Rearranged Spitz Neoplasms: A Retrospective Study Documenting That Bonafide Spitz Melanomas Are Rare.

Previous studies regarding the clinical behavior of Spitz neoplasms lack genomic characterization. We aim to assess our hypothesis that most MAP3K8 Spitz neoplasms are indolent despite MAP3K8 being the single most common driver of Spitz melanoma. Further, we aim to identify genomic features associated with aggressive behavior and to better characterize the morphology of these cases. We analyzed the outcomes of MAP3K8 Spitz neoplasms. We also performed a meta-analysis of the outcomes of MAP3K8 Spitz from the literature. Morphologic features were compared with other variants of Spitz using a Student t test and χ 2 test. Two of 35 cases resulted in local recurrence and one of these cases had local regional metastasis; all other cases had no evidence of recurrence (mean follow-up time: 33 mo). MAP3K8 Spitz only rarely results in aggressive behavior. Metastatic cases have genomic mutations associated with tumor progression. Morphologically, MAP3K8 Spitz neoplasms frequently showed nodular silhouette, large cell size, epithelioid morphology, and severe nuclear atypia resulting in more frequent diagnosis as Spitz melanoma. Most MAP3K8 Spitz neoplasms have excellent prognoses, apart from rare cases harboring additional genomic abnormalities associated with tumor progression.

Lung adenocarcinomas with isolated TP53 mutation: A comprehensive clinical, cytopathologic and molecular characterization.

TP53 mutation is present in about 50.8% of lung adenocarcinomas, frequently in combination with other genetic alterations. However, a rare subset harbors the TP53 mutation alone. Next-generation sequencing was performed in 844 lung adenocarcinomas diagnosed by fine needle aspiration. Fourteen cases (1.7%) showed isolated TP53 alteration and were subjected to a comprehensive analysis. The average age at diagnosis was 65.7 years (range 48-79); 9 males and 5 females. All were smokers with an average pack-year of 40.7 (range 10-70). Ten had metastases, mostly in the brain (n = 4) and pleura (n = 4). After a follow-up period of up to 102 months, 9 died, 3 were alive free of disease, 1 was alive with disease, and 1 was lost to follow-up. The median survival was 12.2 months. Most tumors exhibited poor differentiation, composed of solid sheets with moderate to severe atypia, increased mitotic activity, and necrotic background. Half were positive for TTF-1 and showed p53 overexpression. PD-L1 was positive in 5 cases. Most alterations were missense mutations in exons 5-8, and this mutation type was associated with p53 overexpression. Tumors with combined missense mutation and truncated protein had higher PD-L1 expression along with a trend towards an increase in tumor mutational burden (TMB). CEBPA deletion of undetermined significance was the most common copy number alteration. Isolated TP53 mutation was seen in association with smoking, high-grade cytomorphologic features, adverse prognosis, and recurrent CEBPA deletions. These tumors tend to have strong PD-L1 expression and high TMB, suggesting potential benefit from immune checkpoint inhibitors. Hence, the recognition of this molecular group has prognostic and therapeutic implications.

Transplantation of mitochondria from human malignant tumor cells as a method of tumor growth formation in the lungs of laboratory animals

Purpose of the study. Obtaining lung cancer tumors in Balb/c Nude mice by transplantation of mitochondria isolated from human malignant tumors.Materials and methods. Human lung cancer mitochondria were isolated using differential centrifugation on a high-speed refrigerated centrifuge. Mitochondrial samples were diluted with 0.9 % NaCl solution to a protein concentration of 3 mg per animal. Freshly isolated lung cancer mitochondria were once transplanted into the tail vein of male Balb/c Nude mice (n = 6) at the rate of 3 mg of protein per 1 animal in 0.4 ml of saline. Male mice of Balb/c Nude line (n = 4), which were injected with 0.4 ml of physiological solution into the tail vein once a day, served as a control group. All animals were killed by guillotine decapitation 4 months after intravenous transplantation of mitochondria isolated from lung cancer.Results. After the introduction of mitochondria into the tail vein of mice, no changes were found in the animals’ behavior, coloration of coverings. No respiratory problems, and no allergic reactions to the introduction of foreign protein were detected. Respiratory problems in mice with mitochondrial transplantation occurred between days 113 and 123, when a drop in body weight ≥ 25 % was observed. A uniform formation of tumor nodes together with an active filling of the lung space with blood was clearly visible on lung preparations of a Balb/c Nude male mouse after intravenous transplantation of mitochondria from the lung of a patient with non-keratinizing squamous cell carcinoma. Similar characteristics of tumor growth in the lung parenchyma of the patient and Balb/c Nude mice as direct recipients of tumor mitochondria involved solid structures consisting of fields, cells and strands of tightly fitting atypical polymorphic cells of the squamous epithelium with poorly developed cytoplasm. In addition, signs of adenocarcinoma included glandular and papillary-like structures and cell complexes with large nucleoli. Squamous epithelial cells were characterized by severe atypia and polymorphism. The shape of the nuclei was irregular in most cells, with large sizes, the color was heterogeneous, and the nucleoli were enlarged. Multinucleated cells, as well as pathological mitoses with clearly marked division figures, which testified to their proliferative activity, were encountered with a rather high frequency.Conclusions. Application of intravenous transplantation of mitochondria isolated from malignant human lung tumor in male mice of Balb/c Nude line causes growth and development of malignant foci in male Balb/c Nude mice. This is previously unknown fact in experimental oncology, allowing the study of new properties of mitochondria of human cancer cells.

Risk Profile of High-grade Cervical Lesions and Cervical Cancer Considering the Combination of Cytology, HPV Genotype, and Age among Women Undergoing Colposcopy.

The present study aims to establish a risk profile for high-grade cervical lesions and cervical cancer (CIN2 + ) in women undergoing colposcopy at the Hospital do Câncer de Barretos, through the analysis of Human Papillomavirus (HPV) infection, cervical cytology, and patient's age. Retrospective cross-sectional study based on a computerized database of women aged ≥ 18 years old who underwent colposcopy at the Prevention Department of the Hospital do Câncer de Barretos from 2017 to 2019. A total of 3,411 women were included, 58.0% were positive for high-risk-HPV test, with a higher prevalence of CIN2+ for HPV16 (30.3%) and other HPV (45.0%). Cytological findings that suggest invasive cervical cancer (squamous cells or adenocarcinoma), regardless of the status of HPV test, showed 100% diagnosis of CIN2 + , while atypias that suggest high-grade lesions, HSIL and ASC-H, positive for HPV test, showed in 86 and 55.2%, respectively, diagnosis of CIN2 + . ASC-H cytological results among women aged > 40 years old and negative HPV were mainly associated with benign findings. We observed that ≤ CIN1 has a higher prevalence among older women with negative HPV, while for high-grade lesions there is an increase among young women HPV16- and/or 18-positive. In cancer diagnosis, we observed a predominance of HPV 16/18 regardless of the age group. The highest risks of precursor lesions and cervical cancer were found among women with positive HPV 16/18 tests and severe cytological atypia in population screening tests. In addition, cytological findings of ASC-H HPV negative in women > 40 years old usually represent benign findings in histological investigation.

Clinicopathological comparison and assessment of Ki67, p53 and c-myc immunoexpression in carcinoma cuniculatum, verrucous carcinoma and microinvasive squamous cell carcinoma of the oral cavity

ObjectiveTo illustrate the clinicopathological comparison of carcinoma cuniculatum (CC), verrucous carcinoma (VC) and microinvasive squamous cell carcinoma (MISCC) and to compare the immunoexpression Ki67, p53 & c-myc in these entites. Material and methodsClinical and histopathological parameters observed in total 67 cases (12 cases of CC, 22 cases of VC and 27 cases of MISCC). Ki67 & p53 labelling index and c-myc immunoexpression (localization of stain (1: cytoplasmic; 2: nuclear; 3: both), intensity of stain (1: mild; 2: moderate; 3: strong) and distribution of stain in epithelium (1: basal third; 2: up to middle third; 3: up to upper third; 4: invasive islands)). ResultsCC predominantly showed keratin filled crypts, keratin microabscess, microsequestra formation and lymphocytic exocytosis. VC showed broad pushing invasive front, parakeratin plugging along with verrucous projections. Irregular infiltrating rete ridge pattern and severe cytological atypia were findings of MISCC. Ki67 LI was 12.70 % in CC, 23.34 % in VC and 28.27 % in MISCC. p53 LI was 44.167 % in CC, 30.18 % in VC and 29.51 % in MISCC. Ki67 LI showed statistically significance difference between CC and MISCC. Moderate to strong cytoplasmic immunoexpression was found in epithelium as well as in invasive islands of MISCC compared to CC and VC. ConclusionCC shows endophytic epithelium proliferation with mild to moderate dysplasia and no definite invasive front in contrast to VC. High p53 in CC basal cells correlate with more endophytic epithelial proliferation. Significant high Ki67 LI in invasive islands of MISCC supports its aggressive nature. p53, Ki67 and c-myc panel may be helpful as an adjunct in difficult cases with poorly oriented specimens.

Refining the application of PRAME-a useful marker in high CSD and acral melanoma subtypes.

Pathologic discordance affecting patient management may approach 20% in melanocytic cases following specialist review. The diagnostic utility of PRAME has been highlighted in several studies but interpretative challenges exist including its use in severely dysplastic compound nevi showing progression to melanoma in situ, nevoid melanoma, and coexisting nevi with melanoma. We examine the PRAME status of a broad spectrum of melanocytic lesions including challenging, dysplastic nevi with severe atypia from a large Irish patient cohort. Retrospective review of the dermatopathology database was conducted to evaluate the PRAME staining characteristics of two hundred and twenty-one melanocytic lesions using a commercially available PRAME antibody (EPR20330). The proportion of nuclear labeling and intensity of staining was recorded. The sensitivity and specificity of PRAME for in situ and malignant melanocytic lesions was 77% and 100%, respectively. Virtually all of our melanoma in situ from high-cumulative sun damaged (CSD) skin (22/23) and all acral lentiginous melanoma (5/5) were PRAME positive while 80% (8/10) of our lentigo maligna melanoma showed diffuse expression. None of our benign subgroup showed diffuse immunoexpression (0/82), including thirty-seven moderate or severely dysplastic nevi. In all cases of melanoma in situ arising in association with a dysplastic compound nevus (0/10), no immunoexpression was observed in the nevic component while in five cases of melanoma in situ with coexistent, intradermal nevus immunostaining was confined to the in situ component. A total of 100% (2/2) of desmoplastic melanomas and 50% (4/8) of nodular melanomas were PRAME positive. PRAME is a sensitive and highly specific immunostain in the diagnosis of in situ and invasive melanoma and we emphasize its application in the evaluation of high CSD and acral melanoma subtypes as well as in challenging threshold cases.

Malignant Proliferating Pilar Tumor: Clinicopathologic, Immunohistochemical, and Molecular Study of 17 Cases.

Proliferating pilar tumors are rare neoplasms that differentiate toward the outer sheath near the isthmus and can rarely undergo malignant transformation. We performed histopathologic evaluation on 26 benign proliferating pilar tumor (BPPT) and 17 malignant proliferating pilar tumor (MPPT). Ki-67 and p53 immunostains were performed on 13 BPPT and 10 MPPT. Six MPPT cases were successfully analyzed by a next-generation sequencing platform which surveyed exonic DNA sequences of 447 cancer genes and 191 regions across 60 genes for rearrangement detection. Patient demographics and clinical characteristics were similar between the BPPT and MPPT groups. Follow-up data of 16 of 17 MPPT (median, 25mo) showed metastasis in 1 MPPT. The histologic features associated with MPPT include size >2.5cm, adjacent desmoplastic stroma, small nests or cords of atypical epithelium in surrounding stroma, irregular infiltration or borders, abnormal keratinization, large hyperchromatic nuclei, prominent nucleoli, severe cytologic atypia, nuclear pleomorphism, necrosis, and increased mitotic figures. MPPT harbors copy number gains of 15q and losses of 6p and 6q, findings previously reported in BPPT. However, MPPT harbors frequent TP53 mutations as molecular markers of progression. Different from cutaneous squamous cell carcinoma, MPPT more frequently demonstrates low tumor mutational burden and typically lacks a UV signature, suggestive of a different etiologic pathway than squamous cell carcinoma. In summary, with a median follow-up of 25 months, this study shows that MPPT is a biologically indolent carcinoma with rare metastasis. Molecular analyses suggest a non-UV-related pathogenesis with frequent TP53 aberration.

Morphological Characteristics of Various Cells in Esophageal Squamous Dysplasia: Extremely Wide Morphological Spectrum.

The WHO classification of esophageal tumors divides esophageal squamous intraepithelial dysplasia into high and low grades, but does not specify its morphological spectrum. Here, the morphological characteristics of various cells were investigated in esophageal squamous (high-grade) dysplasia, and a morphological spectrum and terminology for this lesion were proposed to avoid misdiagnosis. The clinicopathological data of 540 patients with esophageal squamous dysplasia were analyzed retrospectively. According to the unique cytomorphological characteristics of the lesions and the predominant cell type, the esophageal squamous dysplasia was divided into the following morphological groups: classic type (34.6%, 187/540), basaloid subtype (10.7%, 58/540), spindle-cell subtype (4.6%, 25/540), differentiated subtype (48.9%, 264/540), and verrucous subtype (1.1%, 6/540). Gender, age, and lesions location did not differ among the subtypes (P > 0.05), while Paris classification and lesions diameter significantly differed among the subtypes (P < 0.01). Classic-type cells showed severe atypia. In the basaloid subtype, the cells were small, and resembled basal cells; most of these lesions were of the 0-IIb type with small lesion diameter. In the spindle-cell subtype, the cells and nuclei were spindle-shaped or long and spindle-shaped and arranged in parallel. Differentiated-subtype showed well-to-moderately differentiated cells, and epithelial basal cells were mature. Verrucous-subtype showed well-differentiated cells, and were characterized by verrucous or papillary structures. Esophageal squamous dysplasia has extremely wide morphological spectrum. Awareness of the spectrum of morphological presentations of this lesion, specifically the basaloid subtype, spindle-cell subtype, differentiated subtype, and verrucous subtype, is important for accurate diagnosis.

TAF15::NR4A3 gene fusion identifies a morphologically distinct subset of extraskeletal myxoid chondrosarcoma mimicking myoepithelial tumors.

Extraskeletal myxoid chondrosarcoma (EMC) is a rare sarcoma of uncertain differentiation predominantly arising in deep soft tissue. Its conventional morphologic appearance manifests as a relatively well-circumscribed, multilobular tumor composed of uniform short spindle-to-ovoid primitive mesenchymal cells with deeply eosinophilic cytoplasm arranged in anastomosing cords within abundant myxoid matrix. The genetic hallmark of EMC has long been considered to be pathognomonic gene rearrangements involving NR4A3, which when fused to TAF15, often have high-grade morphology with increased cellularity, moderate to severe cytologic atypia, and rhabdoid cytomorphology. Herein, we describe two cases of EMC with TAF15::NR4A3 fusion that appear morphologically distinct from both conventional and high-grade EMC. Both cases had an unusual biphasic appearance and showed diffuse positivity for p63, mimicking myoepithelial tumors. DNA methylation profiling demonstrated that both cases clearly cluster with EMC, indicating that they most likely represent morphologically distinct variants of EMC. The clinical significance and prognostic impact of this morphologic variance remains to be determined. Molecular testing, including DNA methylation profiling, can help to confirm the diagnosis and avoid confusion with mimics; it adds another layer of data to support expanding the morphologic spectrum of EMC.

Molecular Correlates of Aggressive Behavior and Biological Progression in Testicular Sertoli Cell Tumors

Sertoli cell tumor (SCT) is the second most common type of sex cord-stromal tumor in men, and ∼10% exhibit malignant behavior. Although CTNNB1 variants have been described in SCTs, only a limited number of metastatic cases have been analyzed, and the molecular alterations associated with aggressive behavior remain largely unexplored. This study evaluated a series of nonmetastasizing and metastasizing SCTs using next-generation DNA sequencing to further characterize their genomic landscape. Twenty-two tumors from 21 patients were analyzed. Cases were divided into metastasizing SCTs and nonmetastasizing SCTs. Nonmetastasizing tumors were considered to have aggressive histopathologic features if they exhibited ≥1 of the following: size >2.4 cm, necrosis, lymphovascular invasion, ≥3 mitoses per 10 high-power fields, severe nuclear atypia, or invasive growth. Six patients had metastasizing SCTs, and the remaining 15 patients had nonmetastasizing SCTs; 5 nonmetastasizing tumors had ≥1 aggressive histopathologic feature(s). Gain-of-function CTNNB1 or inactivating APC variants were highly recurrent in nonmetastasizing SCTs (combined frequency >90%), with arm-level/chromosome-level copy number variants, loss of 1p, and CTNNB1 loss of heterozygosity occurring exclusively in CTNNB1-mutant tumors with aggressive histopathologic features or size >1.5 cm. Nonmetastasizing SCTs were almost invariably driven by WNT pathway activation. In contrast, only 50% of metastasizing SCTs harbored gain-of-function CTNNB1 variants. The remaining 50% of metastasizing SCTs were CTNNB1-wild-type and harbored alterations in the TP53, MDM2, CDKN2A/CDKN2B, and TERT pathways. These findings suggest that ∼50% of aggressive SCTs represent progression of CTNNB1-mutant benign SCTs, whereas the remaining ones are CTNNB1-wild-type neoplasms that exhibit alterations in genes of the TP53, cell cycle regulation, and telomere maintenance pathways.

High grade endometrial carcinoma: 4 common issues

Classification of high grade endometrial carcinoma is a daunting task. Morphologic overlap, non-descript histology, overlapping immunohistochemical staining results and a flood of new molecular tests can make this relatively common task incredibly difficult. This case based talk will address such topics as the presence of severe nuclear atypia, solid growth patterns, clear cell carcinoma and the ever growing field of immunohistochemical and molecular testing in these tumours. A histologic and immunohistochemistry based approach to diagnosis, underpinned by recent molecular findings, will be presented to help ease the classification of these difficult lesions.