Unraveling the Molecular Landscape of Uterine Tumor Resembling Ovarian Sex Cord Tumor: Insights From A Clinicopathological, Morphologic, Immunohistochemical, and Molecular Analysis of 35 Cases.

Uterine tumor resembling ovarian sex cord tumor (UTROSCT) is a rare tumor of uncertain lineage and low malignant potential. Most tumors behave in a benign manner, but a subset of UTROSCT exhibit an aggressive clinical course with recurrences and metastases. The recurrent molecular alterations in UTROSCT mostly represent gene fusions involving NCOA1-3. We performed a comprehensive clinicopathological, morphologic, immunohistochemical, and molecular analysis on a cohort of 35 UTROSCT. The tumors exhibited various architectural patterns (diffuse, corded/trabecular, tubular, sertoliform, fascicular, whorled, nested, microfollicular, and pseudoglandular), often in combination. The immunohistochemical analysis confirmed the polyphenotypic immunoprofile, often with coexpression of sex cord-stromal, smooth muscle, and epithelial markers, as well as hormone receptors. Next-generation sequencing RNA analysis revealed recurrent NCOA1-3 gene fusions in 22/32 analyzed cases (69%), including ESR1::NCOA3 (11/22), GREB1::NCOA2 (7/22), ESR1::NCOA2 (3/22), and GREB1::NCOA1 (1/22). Tumor mutation burden was low in all cases. The fusion-positive cases exhibited statistically significant association with whorled architecture, conversely necrosis was associated with fusion-negative status. We did not find a significant relationship between any architectural pattern and GREB1 alterations, but the NCOA2-altered tumors were associated with pseudoglandular architecture. The GREB1-altered cases occurred in older patients and tended to be more often intramural masses compared with ESR1-altered cases. On the contrary, the ESR1-altered cases presented more often like submucosal or polypoid tumors. Two tumors exhibited aggressive behavior with recurrent disease. Both of these cases harbored a GREB1::NCOA2 fusion. Unsupervised hierarchical cluster analysis of our cohort revealed 2 main clusters. The tumors with GREB1 or NCOA2 fusion cluster together, suggesting that there are underlying molecular differences between these cases and cases with ESR1::NCOA3 fusion or without fusion. Our findings contribute to the growing knowledge about a rare neoplasm with currently uncertain biological behavior.

Diagnostic features of metastatic endometrioid carcinoma in a captive black-tufted marmoset (Callithrix penicillata).

A captive marmoset developed metastatic endometrioid carcinoma (EnC), a rare uterine tumor in non-human primates (NHPs). The neoplasm showed marked microscopical malignant and tubulopapillary aspects, immunopositivity for pan-cytokeratin, CK7, estrogen receptor, and a high mitotic index (Ki-67). These features may contribute to the diagnosis and therapeutics of EnC in NHPs.

Uterine Tumors Resembling Ovarian Sex Cord Tumors (UTROSCTs): A Scoping Review of 511 Cases, Including 2 New Cases.

Uterine Tumors Resembling Ovarian Sex Cord Tumors (UTROSCTs) are rare uterine mesenchymal neoplasms with uncertain biological potential. These tumors, which affect both premenopausal and postmenopausal women, usually have a benign clinical course. Nevertheless, local recurrences and distant metastases have been described. By analyzing 511 cases retrieved from individual reports and cases series, we provide here the most comprehensive overview of UTROSCT cases available in the literature, supplemented by two new cases of UTROSCTs. Case 1 was an asymptomatic 31-year-old woman who underwent a laparoscopic resection of a presumed leiomyoma. Case 2 was a 58-year-old postmenopausal woman with abnormal vaginal bleeding who underwent an outpatient hysteroscopic biopsy of a suspicious endometrial area. In both cases, immunohistochemical positivity for Calretinin and Inhibin was noted, typical for a sex cord differentiation. In both cases, total laparoscopic hysterectomy with bilateral salpingo-oophorectomy was performed. In light of the available literature, no pathognomonic clinical or imaging finding can be attributed to UTROSCT. Patients usually present with abnormal uterine bleeding or pelvic discomfort, but 20% of them are asymptomatic. In most cases, a simple hysterectomy appears to be the appropriate treatment, but for women who wish to become pregnant, uterus-preserving approaches should be discussed after excluding risk factors. Age, tumor size, lymphovascular space invasion, nuclear atypia, and cervical involvement are not reliable prognostic factors in UTROSCT. The current research suggests that aggressive cases (with extrauterine spread or recurrence) can be identified based on a distinct genetic and immunohistochemical phenotype. For instance, UTROSCTs characterized by GREB1::NCOA1-3 fusions and PD-L1 molecule expression appear to be predisposed to more aggressive behaviors and recurrence, with GREB1::NCOA2 being the most common gene fusion in recurrent tumors. Hence, redefining the criteria for UTROSCTs may allow a better selection of women suitable for fertility-sparing treatments or requiring more aggressive treatments in the future.

Uterine hemangiopericytoma with cardiac involvement and pulmonary metastasis: A case report and literature review.

Uterine hemangiopericytoma is extremely rare. This article describes a case of uterine hemangiopericytoma. The tumor involved the parauterine vein; extended into the inferior vena cava, right cardiac cavity, and pulmonary artery; and metastasized to the lungs. It was irregular in shape and exhibited the string-of-beads sign on echocardiography, and it was tightly attached to the right ventricular surface and pulmonary artery wall. The patient underwent tumor resection without adjuvant treatment. A pelvic nodule was found 3 months postoperatively and was considered a recurrent lesion.

[MRI Findings of the Uterine Tumors Resembling Ovarian Sex Cord Tumors:Report of Two Cases].

Uterine tumors resembling ovarian sex cord tumors are rarely reported with limited imaging findings.The current study reported two case of uterine tumors resembling ovarian sex cord tumors and described the detailed MRI findings,which would provide valuable imaging evidence for the diagnosis of such tumors.

An update of molecular findings in uterine tumor resembling ovarian sex cord tumor and GREB1-rearranged uterine sarcoma with variable sex-cord differentiation.

Uterine tumor resembling ovarian sex cord tumor (UTROSCT) is a uterine mesenchymal tumor defined histologically by showing sex cord-like growth patterns, such as sheets, nests, trabeculae, cords, or tubules, with/without Sertoli-like or Leydig-like components, and immunohistochemically by exhibiting variable sex cord markers in addition to epithelial, myogenic, and sex hormone markers. Recent years have seen the emergence in UTROSCT of novel fusion genes that involve key genes in sex hormone pathways, including ESR1 and GREB1 as the 5' partner, and (co)activator oncogenes, particularly NCOA1-3, as the 3' partner. While the identification of similar fusions in the majority of cases serves as a strong argument for UTROSCT to be a distinct entity, there is no denying significant clinicopathologic heterogeneity within the disease spectrum, which might to some extent correlate with the different fusion types. The current review gives a summary of the recently identified fusions in UTROSCT, along with their possible clinicopathologic relevance. Also discussed are unsolved issues including the relationship between UTROSCT and so-called GREB1-rearranged uterine sarcoma as well as other uterine mesenchymal tumors harboring similar fusions.

Uterine Tumor Resembling Ovarian Sex Cord Tumor: A Case Report.

Uterine tumors resembling ovarian sex cord tumors (UTROSCTs) are extremely rare, occurring in less than 1% of uterine stromal tumors, and they are considered to have a low malignant potential. Due to the small number of cases, no standard treatment has been defined. A 77-year-old woman with postmenopausal bleeding was admitted to our department. Imaging studies revealed a substantial mass around 30 mm in size on the anterior uterine wall. A total hysterectomy and bilateral salpingo-oophorectomy were performed for further diagnosis and treatment. The tumor revealed histopathological findings of a sex cord-like growth pattern in the form of fascicles, cords, or small nests. Immunohistochemical findings revealed that the tumor cells were positively reactive to alpha-SMA, calretinin, CD99, estrogen receptor, and progesterone receptor, collectively diagnosed as UTROSCT. No recurrence was observed over 12 months after treatment. We experienced the treatment of UTROSCT, an extremely rare tumor that occurs in elderly women. Although most cases of UTROSCT have a benign clinical course, several cases of recurrence and metastasis have been reported. It should be followed up for a long term after treatment.

An enormous pelvic tumor in a 46-year-old woman with an elevated serum CA 125 level, what lies beneath it? Investigation of uterine tumors in postmenopausal women.

Abdominal and pelvic pain with an associated pelvic mass is a very common emergency situation. There is always a management dilemma for most emergency physicians regarding these patients. A 46-year-old postmenopausal woman was admitted to our emergency department (ED) with complaints of massive abdominal distention. Abdominal and pelvis magnetic resonance imaging (MRI) was performed, which revealed a huge pelvic abdominal mass. All tumor markers were within normal limits. However, the ovarian cancer antigen (CA 125) level was elevated. As there was a strong suspicion of malignancy, the patient underwent total abdominal hysterectomy with bilateral salpingo-oophorectomy. Her final histopathology report was suggestive of uterine leiomyoma. Uterine leiomyomas are the most common benign uterine tumors in women. Surgical treatment is the gold standard, especially for older women with severe symptoms and no desire for future fertility. Although the combination of a pelvic tumor and a high-level of CA 125 arouses suspicion of gynecological malignancy, other benign conditions should always be considered in the differential diagnosis. There is limited evidence to support an association between elevated CA 125 levels and uterine fibroids so far. However, conditions such as the coexistence of adenomyosis and tumor size can affect the level of this marker in uterine fibroids.

Endometrial stromal sarcoma: A review of rare mesenchymal uterine neoplasm.

OBJECTIVE: This review aims to analyze the pathological aspects, diagnosis and treatment of rare mesenchymal uterine tumors. METHODS: On August 2019, a systematic review of the literature was done on Pubmed, MEDLINE, Scopus, and Google Scholar search engines. The systematic review was carried out in agreement with the Preferred Reporting Items for Systematic Reviews and Meta-Analyzes statement (PRISMA). The following words and key phrases have been searched: "endometrial stromal sarcoma", "low-grade endometrial stromal sarcoma", "high-grade endometrial stromal sarcoma", "uterine sarcoma", "mesenchymal uterine tumors" and "uterine stromal sarcoma". Across these platforms and research studies, five main aspects were analyzed: the biological characteristics of the neoplasms, the number of cases, the different therapeutic approaches used, the follow-up and the oncological outcomes. RESULTS: Of the 94 studies initially identified, 55 were chosen selecting articles focusing on endometrial stromal sarcoma. Of these fifty-five studies, 46 were retrospective in design, 7 were reviews and 2 randomized phases III trials. CONCLUSION: Endometrial stromal sarcomas are rare mesenchymal uterine neoplasms and surgery represents the standard treatment. For uterus-limited disease, the remove en bloc with an intact resection of the tumor (without the use of morcellation) is strongly recommended. For advanced-stage disease, the standard surgical treatment is adequate cytoreduction with metastatectomy. Pelvic and para-aortic lymphadenectomy is not recommended in patients with Low-grade Endometrial Stromal Sarcoma (ESS), while is not clear whether cytoreduction of advanced tumors improves patient survival in High-grade ESS. Administration of adjuvant radiotherapy or chemotherapy is not routinely used and its role is still debated.

A high dose mode of action for tetrabromobisphenol A-induced uterine adenocarcinomas in Wistar Han rats: A critical evaluation of key events in an adverse outcome pathway framework.

TBBPA is a non-genotoxic flame retardant used to improve fire safety in a wide variety of consumer products. Estimated human exposures to TBBPA are very low (<0.000084 mg/kg-day), relative to the doses (500 and 1000 mg/kg-day of TBBPA) administered in a recent bioassay that resulted in uterine tumors in Wistar Han rats following chronic exposure. As part of an effort to characterize the relevance of the uterine tumors to humans, data and biological knowledge relevant to the progression of events associated with TBBPA-induced uterine tumors in female rats were organized in an adverse outcome pathway (AOP) framework. Based on a review of possible MOAs for chemically induced uterine tumors and available TBBPA data sets, a plausible molecular initiating event (MIE) was the ability of TBBPA to bind to and inhibit estrogen sulfotransferases, the enzymes responsible for sulfation of estradiol. Subsequent key events in the AOP, including increased bioavailability of unconjugated estrogens in uterine tissue, would occur as a result of decreased sulfation, leading to a disruption in estrogen homeostasis, increased expression of estrogen responsive genes, cell proliferation, and hyperplasia. Available data support subsequent key events, including generation of reactive quinones from the metabolism of estrogens, followed by DNA damage that could contribute to the development of uterine tumors. Uncertainties associated with human relevance are highlighted by potential strain/species sensitivities to development of uterine tumors, as well as the characterization of a dose-dependent MIE. For the latter, it was determined that the TBBPA metabolic profile is altered at high doses (such as those used in the cancer bioassay), and thus an MIE that is only operative under repeated high dose, administration. The MIE and subsequent key events for the development of TBBPA-induced uterine tumors are not feasible in humans given differences in the kinetic and dynamic factors associated with high dose exposures in rats relative to human exposure levels to TBBPA.

Effects of High-Intensity-Focused Ultrasound Treatment on Benign Uterine Tumor.

In this study, the effects of high-intensity-focused ultrasound (HIFU) treatment on benign uterine tumor patients were examined. A total of 333 patients diagnosed with fibroids or adenomyosis using diagnostic sonography, treated with HIFU between February 4, 2010 and December 29, 2014 at a hospital in Korea, and followed up for three or six months were selected for this study. Their benign uterine tumor volume was measured, and the effects of HIFU treatment on the volume were analyzed according to age, disease, fertility, and treatment duration. The volume of benign tumors of the uterus changed by age in all age groups after conducting HIFU treatment for 3 and 6 months, respectively. The rate of decrease in individuals' in their twenties was the largest, at 64.9%. When the decreasing volume of benign tumors of the uterus was analyzed by type of disease, the treatment efficacy for adenomyosis was the best, with a decrease of 164.83 cm(3) after 6 months. Myoma had the fastest decreasing rate, at 68.5%. When evaluated on the basis of fertility, the volume of benign tumors of the uterus continued to decrease until 6 months after completing all procedures. The volume has continued to decrease for 6 months after all procedures. This study showed that HIFU treatments for uterine fibroid and adenomyosis is an effective non-invasive therapy via reducing the benign uterine tumor volume. Therefore, the HIFU method might replace other conventional treatment methods.

Diagnostic dilemma in Broad Ligament Leiomyoma with Cystic Degeneration.

UNLABELLED: Fibroids are smooth muscle benign tumors; most commonly arise from uterus but may also rise from extra uterine sites like broad ligament. This case report of broad ligament myoma with extensive cystic degeneration is presented for its rarity and diagnostic challenges as they mimic pelvic adenexal tumors. Mrs. X, 43 years old p5+2, asymptomatic women with no co-morbids presented with mass in abdomen. The MRI showed mix attenuation mass of 19.7 x 16.8 x 13.7cms arising from right side of uterus extending up to epigastrium, with cystic and solid components and ascitic fluid. Resection of mass with abdominal hysterectomy with bilateral salphingo oophrectomy was done. No local or abdominal organ metastases were seen. Histopathology showed left broad ligament leiomyoma weighing 4000 grams with cystic degeneration. CONCLUSION: Huge broad ligament leiomyoma with cystic degeneration and abdominal ascites may cause diagnostic dilemma with ovarian malignancy. This differential diagnosis must be considered before surgery.

The clinical challenge of a uterine cotyledonoid dissecting leiomyoma with adenomyosis: A case report.

Cotyledonoid dissecting leiomyoma (CDL) is a rare uterine tumor with unique clinical and histological features. We present a case of a 46-year-old woman with a 3-month history of left-flank pain radiating to the back. The patient had a history of infertility and a previous miscarriage. Ultrasound revealed a solid tissue mass suggestive of a degenerated fibroid. Laparoscopy identified subserosal leiomyoma and leiomyoma in the broad ligament. Histologically, CDL is characterized by disorganized smooth muscle with hyaline degeneration and no evidence of malignancy. Clinically, CDL can present with a variety of symptoms, including heavy menstrual bleeding, pelvic pain, and infertility. The coexistence of CDL and adenomyosis is exceedingly rare. This case highlights the importance of considering CDL in the differential diagnosis of pelvic mass, malignant neoplasms, and infertility, even with atypical symptoms. It also emphasizes the value of cooperation between clinicians and pathologists for accurate diagnosis and management of CDL. Adenomyosis in this case further complicated the diagnosis and highlighted the need for an index of suspicion for this rare condition.

Uterine Tumor Resembling Ovarian Sex-Cord Tumor (UTROSCT): A Rare Polyphenotypic Neoplasm.

Uterine tumor resembling ovarian sex-cord tumor (UTROSCT) is a rare form of uterine mesenchymal neoplasm. Although UTROSCT generally exhibits benign behavior with a favorable prognosis, this neoplasm is nevertheless classified as being of uncertain malignant potential, given its low rate of recurrence and the fact that it rarely produces metastases (e.g., in the lymph nodes, epiploic appendix, omentum, small bowel, subcutaneous tissue, lungs). Its histogenesis is also uncertain. Typically, UTROSCT occurs in peri-menopausal or menopausal women, but it can sometimes be observed in young women. Usually, this neoplasm can be found in the uterine corpus as a nodular intramural lesion, while it is less frequently submucosal, subserosal, or polypoid/intracavitary. UTROSCT can cause abnormal bleeding, pelvic pain, enlarged uterus, and mass sensation, but sometimes it is found purely by chance. This neoplasm can be considered polyphenotypic on morphological, immunohistochemical, and genetic analyses. Generally, upon microscopic examination, UTROSCT shows a predominant pattern of the cords, nests, and trabeculae typical of sex-cord tumors of the ovary, while immunohistochemically it is characterized by a coexpression of epithelial, smooth muscle, and sex-cord markers. The aim of this review is to report clinical and pathological data and genetic alterations to establish their impact on the prognosis and management of patients affected by this rare entity.

Clinicopathological features and molecular genetic changes in 17 cases of uterine tumor resembling ovarian sex cord tumor.

Uterine tumor resembling ovarian sex cord tumor (UTROSCT) is a rare mesenchymal neoplasm that was recently reported to exhibit recurrent NCOA1-3rearrangement with the most frequent partners ESR1 and GREB1. In this study, the clinicopathological characteristics of 17 UTROSCT cases were summarized; among them, the fusion genes of 12 cases were retrospectively analyzed by targeted RNA sequencing. The mean age of our cohort was 47 years (19-67 y). Although the majority of UTROSCTs had clear boundaries on gross examination, microscopic infiltration into the myometrium was observed in 82.4 % of cases. The tumor cells showed diffuse, trabecular, nested, reticular, pseudopapillary, hollow and solid tubular patterns, expressing sex cord, epithelial, and myogenic markers. Six fusion genes, including ESR1::NCOA3 (n = 4), ESR1::NCOA2 (n = 2), ESR1::CITED2 (n = 2), GREB1::NCOA2 (n = 2), GREB1::NCOA1 (n = 1), and GREB1::NCOA3 (n = 1), were identified. The fusion genes of the three cases with recurrence and metastasis were GREB1::NCOA2, ESR1::NCOA3, and ESR1::CITED2. All 3 cases of recurrent tumors showed infiltrative growth, with moderate to severe dysplasia of tumor cells and different degrees of rhabdomyoid differentiation. This is the first report of the ESR1::CITED2 fusion genes in UTROSCT, and one of the two patients had recurrence and metastasis. Compared with UTROSCT withESR1 rearrangement, UTROSCT with GREB1 rearrangement was more common in elderly patientsand was more likely to present with intramural masses, less sex cord differentiation, poor prognosis, and relapse and metastasis.

Uterine Tumours Resembling Ovarian Sex-Cord Tumors: A Case Report and Review of the Literature.

Uterine tumors resembling ovarian sex-cord tumors (UTROSCT) are thought to develop from pluripotent uterine mesenchymal cells or endometrial stromal cells with secondary sex-cord differentiation. The patient was a 73-year-old postmenopausal woman who had abnormal vaginal bleeding, and she underwent a laparoscopic hysterectomy with bilateral salpingo-oophorectomy. The diagnosis was a case of UTROSCT. A scoping review of the UTROSCT case report present in the literature has been conducted, and 63 articles were found, of which 45 were considered for the 66 clinical cases examined. At the time of diagnosis, six metastatic localizations were found in 59 patients undergoing demolitive surgery (10.2%). Recurrences were diagnosed in 13/59 (22%) patients with multiple locations. A molecular study was performed in 18/66 cases (27.3%) and genetic alterations were found in 10/18 (55.6%) patients. UTROSCTs are considered rare uterine tumors, typically with a favorable prognosis, and are generally considered to have a good prognosis. But, from the review done, they may already manifest themselves at advanced stages, with the possibility of recurrences even at a distance. It would, therefore, be important to be able to define the most aggressive forms and, perhaps, molecular investigation with sequencing could help identify patients most at risk.

A RARE UTERINE TUMOR: DISSEMINATED PERITONEAL LEIOMYOMATOSIS. CLINICAL OBSERVATIONS.

BACKGROUND: Disseminated peritoneal leiomyomatosis (DPL) is an extremely rare benign disease characterized by widespread lesions of the abdominal cavity, pelvis, and retroperitoneal space with tumor nodules of varying size and number, which are benign neoplasms consisting of smooth muscle fibers in their histological structure. AIM: To analyze clinical cases of DPL with a concise review of the current state of the DPL diagnosis and treatment. MATERIALS AND METHODS: We analyzed 5 clinical cases of DPL of female patients aged 39-50 years (mean age 46.2 years) who underwent surgical treatment at the National Cancer Institute from 2010 to 2021. In all 5 patients, the diagnosis of DPL (8898/1) was verified according to pathological (using routine hematoxylin/eosin staining) and immunohistochemical (IHC) studies. RESULTS: All patients underwent surgical treatment with a laparotomy approach, the extent and radicality of which depended on the location and number of tumor lesions. At the time of follow-up, all 5 patients were alive and did not receive any special oncological treatment. CONCLUSIONS: DPL is characterized by a variety of clinical manifestations from polyserositis to acute abdomen, depending on the location and size of the main tumor focus. IHC analysis is the criterion for the final diagnosis, and radical removal of all tumor foci provides the best therapeutic prognosis. The treatment should be carried out in highly specialized cancer centers where surgeons have gained sufficient experience in performing cytoreductive surgery.

Unusual presentation of uterine tumors resembling ovarian sex cord tumor: A rare case report of cervical involvement.

INTRODUCTION AND IMPORTANCE: Cervical localization of uterine tumor resembling an ovarian sex cord tumor is very rare (UTROSCT) and this is the third case reported in the English literature. Given its rarity, the diagnosis is frequently challenging. Our aim was to discuss pathological characteristics and treatment choices of this rare disease happening in a rare location. CASE PRESENTATION: Our case interested a 19-year-old female patient who presented with a lower abdominal pain and irregular menstrual cycles for a duration of two months. Gynecological examination revealed a cervical firm mass. The patient underwent a cervical lumpectomy. Microscopically, the tumor had nested and trabecular/cord patterns. Tumor cells had abundant cytoplasm, ovoid and spindle-shaped nuclei with fine chromatin. Mitoses were < 1/10 HPFs. A delicate vascular network of small capillaries was noted. Immunohistochemical staining showed that tumor cells were positive for Calretinin, AE1/AE3, Desmin, progesteron receptors, SMA and h-caldesmon. Pathological examination concluded to an UTROSCT. CLINICAL DISCUSSION: UTROSC is a rare tumor with only two cases with cervical involvement reported so far. They have an indolent clinical history and thus require a more cautious and less invasive therapeutic decision. The diagnosis remains on the pathological examination. CONCLUSION: This case is original by its location and the age of presentation. Careful follow-up is necessary searching for local recurrence or metastasis.

NCOA1/2/3 rearrangements in uterine tumor resembling ovarian sex cord tumor: A clinicopathological and molecular study of 18 cases.

Recurrent NCOA1/2/3 gene fusions emerged in uterine tumor resembling ovarian sex cord tumor (UTROSCT). More cases are required to consolidate these molecular alterations. In this study, the clinicopathological features and immunostaining profiles were reviewed in 18 UTROSCT. Fluorescence in situ hybridization for dual color break-apart probes of NCOA1, NCOA2, NCOA3, BCOR, YWHAE, PHF1 and JAZF1 were performed on 16 tumors. Eight cases were subjected to targeted next-generation sequencing to detect genomic alterations. We found that the tumors predominantly showed various sex-cord patterns without a recognizable endometrial stromal component. They exhibited a diverse immunohistochemical profile, frequently co-expressing sex cord (calretinin, inhibin, WT1, SF-1, and FOXL2), smooth muscle (SMA, desmin and caldesmon), epithelial (CK) and other markers (CD10 and IFITM1). Fourteen of 16 tumors (87.5%) showed NCOA1-3 gene rearranges, but none had BCOR, YWHAE, PHF1 and JAZF1 fusions. Five tumors contained 6 non-recurrent pathogenic (likely) mutations and one had gains in c-MYC. Our study supports frequent NCOA1-3 rearrangements in UTROSCT. Rare, non-recurrent mutations suggest that these gene rearrangements be potential drivers in tumorigenesis. Detection of gene rearrangements can contribute to the correct interpretation of UTROSCT. However, large comparative studies with molecular tests are required to confirm these findings.

Primary Uterine Alveolar Soft Part Sarcoma in a Postmenopausal Woman: Histopathologic and Immunohistochemical Characteristics of a Rare Case.

BACKGROUND: Primary uterine alveolar soft part sarcoma (ASPS) is a rare, indolent mesenchymal malignancy with less than 40 patients documented in the literature. CASE: We report an example of ASPS in a 61-year-old postmenopausal woman. Macroscopically, the uterus showed multiple nodular masses. Microscopic examination revealed tumor arranged in nests and alveolar pattern. The tumor cells were moderately to markedly pleomorphic, epithelioid to polygonal, with eccentrically placed nuclei, vesicular chromatin, prominent macro-nucleoli, and moderate to abundant eosinophilic cytoplasm. PAS-positive and diastase-resistant intracytoplasmic crystals were also seen in some tumor cells. On immunohistochemistry, the tumor cells showed diffuse positivity for vimentin and nuclear positivity for TFE3, a surrogate marker for ASPS. These were negative for SMA, desmin, CD10, h-caldesmon, cyclin D1, EMA, Melan A, and CD34. SMARCB1 expression was retained. Based on the histopathology and IHC, a final diagnosis of uterine ASPS was rendered. CONCLUSIONS: Knowledge of the characteristic histopathologic and immunohistochemical features can help accurately diagnose such rare tumors. Knowledge of the characteristic histopathologic and immunohistochemical features can help accurately diagnose such rare sarcoma in an uncommon site with an unusual age.