Stromal Nodules Research Articles

Mesenchymale Uterustumoren

Uterine stromal neoplasms are classified into endometrial stromal nodules and stromal sarcomas, as well as undifferentiated sarcomas. The two former groups demonstrate identical histological composition, consisting of small monomorphous cells with scant cytoplasm and round nuclei and typically contain numerous arteriolar-type vessels. Stromal tumors are distinct from stromal nodules by virtue of their myometrial and vascular invasion. Undifferentiated sarcomas consist of polymorphic cells and lack any cytological similarity to the stroma of normal proliferative endometrium. There is no smooth or striated muscle differentiation. Adenosarcomas are mixed neoplasms with a low grade stromal sarcoma component containing benign glands, which are surrounded by condensed neoplastic stroma. Typical uterine tumors resembling ovarian sex cord tumors (UTROSCT Type2) show predominant sex cord differentiation in a well circumscribed nodule. Focal sex cord differentiation may occur in stromal nodules and stromal sarcomas (UTROSCT Type2).

Prostatic Stromal Hyperplasia With Atypia: Follow-up Study of 18 Cases

Prostatic stromal hyperplasia with atypia is a rare lesion that can be mistaken for sarcoma because of the presence of atypical, bizarre, degenerative myocyte nuclei. To determine the diagnostic criteria and clinical significance of prostatic stromal hyperplasia with atypia. Eighteen cases of prostatic stromal hyperplasia with atypia were reviewed from the consultation file of one of the authors (D.G.B.). Prostatic stromal hyperplasia with atypia consists of 1 or more ill-defined, uncircumscribed, hyperplastic stromal nodules, with variable numbers of atypical, bizarre giant cells, with vacuolated nuclei, smudged chromatin, and frequent multinucleation infiltrating around benign acini. There was a hypocellular, loose, myxoid stromal matrix, with ectatic hyalinized vessels and mild to moderate chronic inflammation. Stromal cells displayed intense immunoreactivity for androgen receptors and vimentin, but moderate reactivity for desmin and actin. There were 3 local recurrences, with a mean follow-up of 6.3 years (range, 0.5-14 years), but none developed evidence of sarcomatous transformation or malignancy. Prostatic stromal hyperplasia with atypia is a rare, benign lesion, composed of degenerative myocytes with atypia that is histologically and clinically reminiscent of benign counterparts in the myometrium, breast, vulva, vagina, and elsewhere. Recognition of this distinctive entity should allow separation from phyllodes tumor and sarcoma of the prostate. The phrase stromal tumor of uncertain malignant potential is inappropriate for this benign tumor, and its use is discouraged.

Prostatic stromal hyperplasia with atypia: follow-up study of 18 cases.

Abstract Context.—Prostatic stromal hyperplasia with atypia is a rare lesion that can be mistaken for sarcoma because of the presence of atypical, bizarre, degenerative myocyte nuclei. Objective.—To determine the diagnostic criteria and clinical significance of prostatic stromal hyperplasia with atypia. Design.—Eighteen cases of prostatic stromal hyperplasia with atypia were reviewed from the consultation file of one of the authors (D.G.B.). Results.—Prostatic stromal hyperplasia with atypia consists of 1 or more ill-defined, uncircumscribed, hyperplastic stromal nodules, with variable numbers of atypical, bizarre giant cells, with vacuolated nuclei, smudged chromatin, and frequent multinucleation infiltrating around benign acini. There was a hypocellular, loose, myxoid stromal matrix, with ectatic hyalinized vessels and mild to moderate chronic inflammation. Stromal cells displayed intense immunoreactivity for androgen receptors and vimentin, but moderate reactivity for desmin and actin. There were 3 loc...

Prostatic leiomyoma with atypia: follow-up study of 10 cases

We studied the clinical and histologic features of 10 cases of prostatic leiomyoma with atypical bizarre nuclei. Immunohistochemical studies were undertaken in 6 cases. Patient follow-up was obtained in all cases. Patients ranged in age from 50 to 82 years (mean, 65 years) and presented with urinary obstructive symptoms in 7 cases, abnormal digital rectal examination in 3 cases. The histologic findings consisted of a solid circumscribed expansile stromal nodule with abundant smooth muscle and variable numbers of atypical bizarre giant cells. The cells of the tumor displayed intense immunoreactivity for desmin, actin, and androgen receptor and weak to moderate reactivity for vimentin. Four local recurrences were seen, with a follow-up for 3 to 16 years (mean, 7.4 years), but no evidence of sarcomatous transformation occurred. Despite worrisome histologic appearance, a benign clinical behavior was seen in all cases.

Diagnostic use of nuclear Β-catenin expression for the assessment of endometrial stromal tumors

Alterations in Β-catenin degradation cause it to accumulate to immunohistochemically detectable levels in the nuclei of tumor cells. Although it has been shown that nuclear Β-catenin immunostaining is useful for the diagnosis of some mesenchymal tumors, there is little known about Β-catenin expression in endometrial stromal tumors. In this study, nuclear Β-catenin immunoreactivity was evaluated in normal endometrium and endometrial mesenchymal tumors and then compared with that of CD10. The endometrial mesenchymal tumors evaluated included endometrial stromal nodules (n=2), low-grade endometrial stromal sarcomas (n=12), undifferentiated endometrial sarcomas (n=8) and uterine cellular leiomyomata (n=9). In addition, direct DNA sequencing of Β-catenin exon 3 was conducted in 15 endometrial stromal tumors. Normal endometrial stromal cells showed strong cytoplasmic reactivity for CD10 but no detectable reactivity for Β-catenin. Nuclear Β-catenin immunoreactivity was detected in 11 low-grade endometrial stromal sarcomas (92%) and 6 undifferentiated endometrial sarcomas (75%). Ten low-grade endometrial stromal sarcomas (83%) and six undifferentiated endometrial sarcomas (75%) were positive for CD10. Eight low-grade endometrial stromal sarcomas (67%) exhibited diffuse, strong nuclear immunoreactivity with Β-catenin, whereas only four cases (33%) expressed diffuse, strong immunoreactivity with CD10. All nine cases of uterine cellular leiomyomata were completely negative for both CD10 and Β-catenin. Β-catenin mutations were rare in endometrial stromal tumors. Taken together, these results indicate that nuclear Β-catenin immunostaining can serve as a sensitive immunohistochemical marker for the diagnosis of endometrial stromal tumors and is useful for differentiating low-grade endometrial stromal sarcomas from uterine cellular leiomyomata.

Endometrial stromal nodule with smooth muscle differentiation

Uterine tumors composed of a prominent component of smooth muscle and endometrial stroma (so-called stromomyoma) are distinctly uncommon. This article describes the morphological features of one such tumor discovered as an incidental finding in a hysterectomy specimen of a 49-year-old lady with a clinical diagnosis of dysfunctional uterine bleeding. Morphological and immunohistochemical (IHC) evaluation were performed and a final diagnosis of endometrial stromal nodule with smooth muscle differentiation was rendered.

Endometrial stromal nodule embedded into term placenta

A 28-year-old patient presented with a 5 cm endometrial stromal tumor situated at the uteroplacental interface, which was diagnosed ultrasonographically at the 28th week of pregnancy. The tumor was asymptomatic and closely attached to the decidua; after a normal term delivery, it was revealed to be embedded within the placenta. Microscopically, the neoplasm had a high mitotic rate and characteristic features of endometrial stromal tumor, such as CD10, progesterone receptor positivity, and an expansile linear, non-infiltrative pushing border. There were also pregnancy-related changes such as decidualization and myxoid change. In conclusion, the lesion was considered a benign endometrial stromal nodule with an unusual morphology and increased proliferation rate due to the hormonal stimuli of pregnancy.

High Frequency of JAZF1-JJAZ1 Gene Fusion in Endometrial Stromal Tumors With Smooth Muscle Differentiation by Interphase FISH Detection

The most common cytogenetic alteration observed in low-grade endometrial stromal tumors (EST) is the t(7;17)(p15;q21) translocation, resulting in the fusion of the JAZF1 and JJAZ1 genes. By reverse-transcription polymerase chain reaction, the translocation has been detected overall in one-third of ESTs, but only rarely in its variants. The purpose of this study was to develop a fluorescence in situ hybridization assay for detection of this translocation using archival paraffin-embedded samples of ESTs with smooth muscle differentiation and to assess the nature of the smooth muscle component of these tumors. Representative paraffin blocks of 9 endometrial stromal nodules and 1 low-grade endometrial stromal sarcoma were collected for the study. In 1 case, the block selected also contained areas of sex cordlike differentiation. A fluorescence in situ hybridization probe set was designed to detect the t(7;17)(p15;q12) on tissue sections. Six out of 10 collected ESTs were assessable. Fusion signals were detected in 3 out of 6 cases (50%) in both the conventional endometrial stromal and the smooth muscle components of the tumors. The tumor sample with sex cordlike differentiation harbored the fusion signal in all the 3 components. Our results support the contention that the endometrial stromal and smooth muscle components of these tumors have the same origin, either from a common precursor cell with pluripotential differentiation or from endometrial stromal cells that have undergone smooth muscle metaplasia. Our results indicate that the detection of this chromosomal abnormality can be used to diagnose ESTs with smooth muscle differentiation when the smooth muscle component is predominant.

Endometrial stromal lesions: a morphological and immunohistochemical study of short series

Endometrial stromal tumours are rare and constitute less than 5% of uterine tumours. This study presents our experience of endometrial stromal tumours and their immunohistochemical profile. All cases reported as endometrial stromal tumors from January 2001 to December 2004 were extracted from the files of pathology department. Hematoxylin and eosin stained slides were reviewed and immunohistochemical staining for vimentin, desmin and cytokeratin was done in all cases. In all five cases of endometrial stromal tumors were retrieved from the records and constituted 0.3% of endometrial neoplasms. One case was diagnosed as endometrial stromal nodule and four cases were diagnosed as low-grade endometrial stromal sarcoma. Four out of five cases were confined to the uterine corpus. Only one case showed spread to the cervix and the fallopian tube. All tumors were negative for desmin and cytokeratin and showed only focal vimentin positivity. The diagnosis rests on morphological features mainly while immunohistochemical profile of these tumours is rather inconsistent.

Morphologic Changes in the Endometrium Associated With the Use of the Mirena Coil: A Retrospective Study of 106 Cases

This study outlines the histologic changes seen in 106 endometrial specimens after use of the Mirena coil (levonorgestrel) and compares these changes with previous studies. The variables assessed include nature of the endometrial glands, metaplastic glandular changes, nuclear atypia, hobnail change, and endometrial hyperplasia. Stromal changes include pseudodecidualization, mucinous change, ulceration, and infiltration by granulocytes, neutrophils, and plasma cells, and stromal hyaline nodules, a feature not described previously. Additional changes include superficial micropapillary change, infarcted decidua, dystrophic calcification, hemosiderophages, polypoid indentations, cervical microglandular hyperplasia and endocervical pseudodecidualization. These variables are compared with a similar previous study. Significant differences in the incidence of glandular metaplasia, dystrophic calcification, plasma cell infiltrates, hemosiderophages, and presence of nuclear atypia are noted. With increased use of the Mirena coil, histopathologists need to be aware of the characteristic and constant endometrial changes due to progestogenic and mechanical effects, despite a wide variation in the duration of usage.

Molecular genetic changes in epithelial, stromal and mixed neoplasms of the endometrium

Endometrial carcinoma, endometrial stromal tumours and mixed malignant mesodermal tumours (MMMT) develop along distinctive molecular genetic pathways. Two distinctive types of endometrial carcinoma are distinguished, type I and type II, which develop along distinctive pathways and show different clinical behaviour and histological features. Type I carcinomas show endometrioid histology, are oestrogen-related and develop from atypical endometrial hyperplasia. The molecular tumorigenesis is comparable to colorectal carcinoma with a step-like progression and an accumulation of genetic alterations. Alterations of PTEN, K-Ras mutations and microsatellite instability are frequent and early events in type I carcinoma, whereas p53 mutations occur during progression to grade 3 carcinoma. Serous and clear cell carcinomas are considered type II carcinomas which are mostly unrelated to oestrogen. p53 mutations occur in almost all serous carcinomas and seem to occur early, leading to massive chromosomal instability and rapid tumour progression. Gene expression profiling has supported this dualistic model of endometrial carcinoma. There is evidence of molecular differences between serous and clear cell carcinomas as well as between endometrioid carcinomas with and without microsatellite instability. A dualistic model of tumorigenesis may be also suggested for endometrial stromal tumours. Endometrial stromal sarcomas (ESS; type I endometrial sarcoma) are oestrogen-related and seem to develop from endometrial stromal nodules (ESN). They are histologically and genetically distinct from undifferentiated endometrial sarcoma (UES) which seem to be mostly unrelated to oestrogen (type II endometrial sarcoma). ESS and ESN share the fusion gene JAZF1/JJAZ1 caused by a t(7;17)(p15;q21) translocation, whereas UES lacks a distinctive molecular alteration so far. In MMMT, which is considered a metaplastic carcinoma, p53 alteration occurs early, before clonal expansion and acquisition of genetic diversity during progression.

Meningioma‐like endometrial stromal nodule with a stromal‐derived foam cell component

HistopathologyVolume 49, Issue 3 p. 312-315 Meningioma-like endometrial stromal nodule with a stromal-derived foam cell component E E Mooney, E E Mooney Departments of Pathology, National Maternity Hospital, Dublin, Ireland, Institute of Pathology, University of Graz, Graz, AustriaSearch for more papers by this authorS Regauer, S Regauer Departments of Pathology, National Maternity Hospital, Dublin, Ireland, Institute of Pathology, University of Graz, Graz, AustriaSearch for more papers by this authorJ Merino, J Merino University of Granada, SpainSearch for more papers by this authorF F Nogales, F F Nogales University of Granada, SpainSearch for more papers by this author E E Mooney, E E Mooney Departments of Pathology, National Maternity Hospital, Dublin, Ireland, Institute of Pathology, University of Graz, Graz, AustriaSearch for more papers by this authorS Regauer, S Regauer Departments of Pathology, National Maternity Hospital, Dublin, Ireland, Institute of Pathology, University of Graz, Graz, AustriaSearch for more papers by this authorJ Merino, J Merino University of Granada, SpainSearch for more papers by this authorF F Nogales, F F Nogales University of Granada, SpainSearch for more papers by this author First published: 18 August 2006 https://doi.org/10.1111/j.1365-2559.2006.02439.xCitations: 2Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume49, Issue3September 2006Pages 312-315 RelatedInformation

Spontaneous Fractures in the Mouse Mutant sfx Are Caused by Deletion of the Gulonolactone Oxidase Gene, Causing Vitamin C Deficiency

Using a mouse mutant that fractures spontaneously and dies at a very young age, we identified that a deletion of the GULO gene, which is involved in the synthesis of vitamin C, is the cause of impaired osteoblast differentiation, reduced bone formation, and development of spontaneous fractures. A major public health problem worldwide, osteoporosis is a disease characterized by inadequate bone mass necessary for mechanical support, resulting in bone fracture. To identify the genetic basis for osteoporotic fractures, we used a mouse model that develops spontaneous fractures (sfx) at a very early age. Skeletal phenotype of the sfx phenotype was evaluated by DXA using PIXImus instrumentation and by dynamic histomorphometry. The sfx gene was identified using various molecular genetic approaches, including fine mapping and sequencing of candidate genes, whole genome microarray, and PCR amplification of candidate genes using cDNA and genomic DNA as templates. Gene expression of selected candidate genes was performed using real-time PCR analysis. Osteoblast differentiation was measured by bone marrow stromal cell nodule assay. Femur and tibial BMD were reduced by 27% and 36%, respectively, in sfx mice at 5 weeks of age. Histomorphometric analyses of bones from sfx mice revealed that bone formation rate is reduced by >90% and is caused by impairment of differentiated functions of osteoblasts. The sfx gene was fine mapped to a 2 MB region containing approximately 30 genes in chromosome 14. By using various molecular genetic approaches, we identified that deletion of the gulonolactone oxidase (GULO) gene, which is involved in the synthesis of ascorbic acid, is responsible for the sfx phenotype. We established that ascorbic acid deficiency caused by deletion of the GULO gene (38,146-bp region) contributes to fractures and premature death because the sfx phenotype can be corrected in vivo by treating sfx mice with ascorbic acid and because osteoblasts derived from sfx mice are only able to form mineralized nodules when treated with ascorbic acid. Treatment of bone marrow stromal cells derived from sfx/sfx mice in vitro with ascorbic acid increased expression levels of type I collagen, alkaline phosphatase, and osteocalcin several-fold. The sfx is a mutation of the GULO gene, which leads to ascorbic acid deficiency, impaired osteoblast cell function, and fractures in affected mice. Based on these and other findings, we propose that ascorbic acid is essential for the maintenance of differentiated functions of osteoblasts and other cell types.

JAZF1/JJAZ1 Gene Fusion in Endometrial Stromal Sarcomas : Molecular Analysis by Reverse Transcriptase-Polymerase Chain Reaction Optimized for Paraffin-Embedded Tissue

Endometrial stromal tumors are rare uterine neoplasms including benign stromal nodules, low-grade endometrial stromal sarcomas (ESS), and undifferentiated endometrial sarcomas (UES), the latter representing the most aggressive form. Morphological characteristics and cytogenetic abnormalities are heterogeneous, making diagnosis difficult. Recently, a gene fusion on chromosome 7 that includes two zinc-finger genes (JAZF1 and JJAZ1) has been discovered in these tumors. Hitherto only 31 cases, described by three different research groups, have shown JAZF1/JJAZ1 fusion in approximately 50% of all analyzed low-grade ESSs whereas it is less frequent in UESs. In this study we analyzed 20 ESS and 2 UES cases using two-step reverse transcriptase-polymerase chain reaction optimized for formalin-fixed, paraffin-embedded tissue. In our subset of samples, the JAZF1/JJAZ1 fusion transcript occurred in 80% of analyzed ESS cases and in none of two UES cases. In comparison to published data, our results identified the JAZF1/JJAZ1 gene fusion more frequently in endometrial stromal tumors than hitherto presumed. This cytogenetic abnormality was not present in normal endometria, leiomyomas, or leiomyosarcomas or in lung, gastric, or hepatic carcinomas, indicating its specificity for endometrial stromal tumors. In combination with other established methods, accurate reverse transcriptase-polymerase chain reaction analysis of JAZF1/JJAZ1 gene fusion may be useful in diagnosing difficult or unusual ESS/UES cases.

An endometrial stromal tumor with osteoclast-like giant cells

Endometrial stromal tumors (ESTs) of the uterine corpus have a striking propensity to display diverse morphological variations, including sex cord-like, smooth muscle, or skeletal muscle differentiation; fibrous change; myxoid change; or bland endometrioid-type glands. They may also contain rhabdoid, foam, clear, or epithelioid/granular cells among others. Recently, we have encountered an EST showing smooth muscle differentiation and osteoclast-like giant cells that were predominantly concentrated in the areas showing smooth muscle differentiation. Osteoclastlike giant cells have not been previously reported in EST to our knowledge; thus, this finding expands the morphological spectrum of these tumors. In addition, although the level of infiltration at the peripheries of the tumor exceeded that allowable under the Tavassoli and Norris criteria for stromal nodules, it did not reach the classic permeative infiltration generally associated with endometrial stromal sarcomas. Historical, prognostic, and diagnostic aspects of margins in EST, especially in those borderline cases such as ours, are also discussed.

Utility of MIB-1 and estrogen and progesterone receptor in distinguishing between endometrial stromal sarcomas and endometrial stromal nodules, highly cellular leiomyomas

It is difficult to differentiate between an endometrial stromal nodule (ESN) and endometrial stromal sarcoma (ESS) in curettage specimen, and the recommended therapy of endometrial stromal neoplasm is hysterectomy. If we could discriminate ESS from ESN in curettage specimens, there would be an opportunity to treat ESN by local excision rather than by hysterectomy. We analyzed MIB-1 and estrogen and progesterone receptor (ER/PR) expression in a retrospective series of 8 ESSs, 7 ESNs, and 17 highly cellular leiomyomas obtained from hysterectomy specimens. ESSs expressed MIB-1 more frequently than ESNs (P < 0.05), and ESSs had a tendency to express ER less frequently than ESNs (P= 0.08). We observed that in spite of showing MIB-1 expression to some extent, highly cellular leiomyomas usually could not reach ESSs' level and frequency of MIB-1 expression in the current study. Although MIB-1 and ER appear to be promising markers in the differential diagnosis of ESSs, a larger study would be necessary to confirm their validity.

Utility of MIB-1 and estrogen and progesterone receptor in distinguishing between endometrial stromal sarcomas and endometrial stromal nodules, highly cellular leiomyomas

It is difficult to differentiate between an endometrial stromal nodule (ESN) and endometrial stromal sarcoma (ESS) in curettage specimen, and the recommended therapy of endometrial stromal neoplasm is hysterectomy. If we could discriminate ESS from ESN in curettage specimens, there would be an opportunity to treat ESN by local excision rather than by hysterectomy. We analyzed MIB-1 and estrogen and progesterone receptor (ER/PR) expression in a retrospective series of 8 ESSs, 7 ESNs, and 17 highly cellular leiomyomas obtained from hysterectomy specimens. ESSs expressed MIB-1 more frequently than ESNs (P&lt; 0.05), and ESSs had a tendency to express ER less frequently than ESNs (P= 0.08). We observed that in spite of showing MIB-1 expression to some extent, highly cellular leiomyomas usually could not reach ESSs' level and frequency of MIB-1 expression in the current study. Although MIB-1 and ER appear to be promising markers in the differential diagnosis of ESSs, a larger study would be necesary to confirm their validity.

Endometrial stromal tumor with limited infiltration and probable extrauterine metastasis: report of a case

Endometrial stromal nodule (ESN) is a tumor composed of cells closely resembling those of the endometrial stroma with minimal cytologic atypia. The most important criterion for the differential diagnosis from the endometrial stromal sarcoma (ESS) is a well-defined noninfiltrative expansile border. However, the definition of the ESN also includes a tumor with the presence of focal irregularities or fingerlike projections of the margin into the adjacent myometrium, none of which exceeds 2 to 3 mm. In some cases, however, it is difficult to differentiate marginal irregularities of ESN from "true invasion" of ESS. We described a case of extrauterine ESS that was associated with small intramyometrial stromal lesions with limited infiltration. The intramyometrial lesion could be definitionally categorized as ESNs. However, peritumoral fibroblastic band and inflammatory stromal reactions, irregular fingerlike projections, and multiple concurrent extrauterine ESS strongly suggested that these were small primary focus of ESS mimicking ESN. We propose that the patient with endometrial stromal tumor with limited infiltration should be more carefully followed than the usual ESN for possible metastasis and that a hysterectomy with meticulous histological examination of the specimen be performed before a diagnosis of primary extrauterine ESS is made, even in a case showing a grossly or radiologically normal uterus.

Allelic imbalances in endometrial stromal neoplasms: frequent genetic alterations in the nontumorous normal-appearing endometrial and myometrial tissues

Objectives Endometrial stromal sarcoma (ESS) is among the rarest primary malignant tumors of the uterus. The aim of this study was to examine the possibility of loss of heterozygosity (LOH) and microsatellite instability (MIS) in different tissue components of ESS. Methods and materials Using PCR, we examined DNA extracts from microdissected tissues of 27 uterus samples containing malignant stromal cells of ESS (20 low grade and 3 high grade sarcomas), benign tumor cells of endometrial stromal nodules (ESN, 4 cases) as well as tumor-free myometrial and endometrial tissues close to and distant from the tumors. Normal cervical tissues (epithelial cells, stroma cells) were also microdissected and analyzed. Fifteen polymorphic DNA markers (chromosomes 2p, 3p, 5q, 10q, 11q, 13q, and 17p) were tested to identify possible genetic alterations. Samples from 10 women with prolapsed uteri without any histopathologic abnormalities were also selected as controls. Results While no genetic alterations could be identified in 12 (44.5%) ESS cases, 15 (55.5%) revealed LOH with at least one polymorphic DNA marker. LOH were found in 3 (100%) high-grade sarcomas, 10 (50%) low-grade ESS, and 2 (50%) benign ESN. Although LOH was found more often in the neoplastic stromal cells, several cases showed concurrent and independent LOH in the tumor-free myometrial or endometrial tissues either close to or distant from the tumors. The most common genetic abnormality (LOH) was observed at PTEN, a tumor suppressor gene located on chromosome 10q. No tumor was associated with microsatellite instability (MSI). The control group without any histologic abnormalities did not show LOH or MSI. Conclusions The frequent occurrence of LOH and the lack of MSI suggest that loss of function(s) of tumor suppressor genes and not mismatch repair deficiency plays a key role in the pathogenesis of endometrial stromal neoplasms. The concurrent and independent occurrence of LOH in the stromal tumor cells and the tumor-free and normal-appearing myometrial and endometrial tissues strongly support the concept of genetic alterations in microenvironmental tissues and the interaction(s) between different tissue components in the development and progression of endometrial stromal neoplasms.

Characteristics of patients with endometrial stromal sarcoma

5145 Background: Endometrial stromal sarcoma (ESS) is by definition a low grade sarcoma, accounting for less than 1% of all tumor malignancies. The prevalence is approximately 2 per million women. By comparison, the prevalence of endometrial cancer is 700 per million women. Because of its rarity, the natural history of the disease and the optimal therapy have not been well established. Methods: After IRB approval, the charts of 78 patients diagnosed for the first time with ESS and treated at the University of Texas MDACC were reviewed, with emphasis on patient demographics, therapies, recurrence, and survival. Patients with stromal nodule, high grade ESS (undifferentiated sarcoma), or other sarcomas were excluded. Results: The median age of 78 patients was 43 (range 20–78), 85% were Caucasian, and 37% had received exogenous hormones before diagnosis. Endometrial FIGO stage was I in 52%, II in 6%, III in 30%, and IV in 12%. The primary site was uterus in 87% and extra-uterine in 13%. The median parity was 2. Among 68 patients, 78% were postmenopausal. The two-year recurrence rate was 25% and the five year recurrence rate was 51%. The five-year survival rate was 81%. Conclusions: Our study represents 36 years of collected data from MDACC. The demographic data has been recorded and tabled. The median age of onset is younger than the one of endometrial cancer, but interestingly about 75% are postmenopausal at diagnosis. The prognosis is usually good. Various treatments including hormonal therapy, chemotherapy, radiation therapy, and hysterectomy with oophorectomy have been used, and we plan to study their impact on this disease, to present at the annual meeting. No significant financial relationships to disclose.