Endometrial stromal tumours of the uterus: a practical approach using conventional morphology and ancillary techniques

Case Series of Incidental Findings of Low-Grade Endometrial Stromal Sarcoma on Routine Hysterectomy for Uterine Fibroids

This study is a retrospective review of data from patients who were incidentally diagnosed with endometrial stromal sarcoma after a routine hysterectomy for uterine fibroid at the Department of Gynaecologic Oncology in a tertiary care hospital. The Institutional Review Board (IRB) gave its clearance for this study before it was carried out. Informed written consent was obtained from all patients. In our case series, the three patients presented with complaints of menorrhagia, lower abdominal pain, intermenstrual bleeding, and acute retention of urine. After the patients underwent a clinical examination and radiological scan, the diagnosis of fibroids was made. They underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy. Histology revealed low-grade endometrial stromal sarcoma (LGESS). The patients were observed for adjuvant therapy. The patients had a follow-up period of 18-24 months. In LGESS, which is rare, prompt management is of utmost importance, because the tumour's stage is the most significant predictor of the prognosis. As there are no clear indications to suggest the presence of LGESS prior to the histopathology of the specimen, it is necessary to analyze the data of patients who are diagnosed with LGESS, in order to investigate and manage the condition more appropriately. After myomectomy for a suspected leiomyoma, there is a 0.2% chance of the result showing endometrial stromal sarcoma.

Uterine sarcomas: clinical practice guidelines for diagnosis, treatment, and follow-up, by Spanish group for research on sarcomas (GEIS)

Uterine sarcomas are very infrequent and heterogeneous entities. Due to its rarity, pathological diagnosis, surgical management, and systemic treatment are challenging. Treatment decision process in these tumors should be taken in a multidisciplinary tumor board. Available evidence is low and, in many cases, based on case series or clinical trials in which these tumors have been included with other soft tissue sarcoma. In these guidelines, we have tried to summarize the most relevant evidence in the diagnosis, staging, pathological disparities, surgical management, systemic treatment, and follow-up of uterine sarcomas.

A Case of Endometrial Carcinosarcoma Containing Sertoliform Endometrioid Carcinoma Component

Carcinosarcomas (CSs) of the endometrium have admixture of malignant epithelial and mesenchymal components. The carcinomatous component exhibit endometrioid, serous, or clear cell differentiation, or are undifferentiated. CSs are considered homologous or heterologous according to the type of sarcomatous component. Sertoliform endometrioid carcinomas (SECs) of the endometrium which comprise a rare subtype of endometrial cancer, typically occur in the ovary. SECs as a carcinomatous component of CS of the endometrium have not been reported. Here, we report an endometrial carcinosarcoma that contains an SEC component. An 88-year-old female presented to a clinic with atypical genital bleeding. She was referred to our hospital and underwent total hysterectomy, bilateral adnexectomy and partial omentectomy due to endometrial carcinoma. Gross examination revealed a polypoid mass in the uterine cavity with massive myometrial invasion. Histologically, the tumor was a high-grade endometrioid carcinoma. In addition to an ordinary conventional endometrioid carcinoma, approximately 30% of the area exhibited sex cord-like pattern and contained small hollow tubules, anastomosing cords and trabeculae, and tightly packed nests. Immunohistochemically, the SEC component showed diffuse p53 staining. Sex cord-like area, especially the solid area, showed positive staining for EMA, vimentin, α-inhibin, CD99, calretinin, p53, CD56, synaptophysin, and chromogranin A, which is a staining pattern similar to that previously reported SEC of the endometrium. Diminished membranous and positive cytoplasmic staining for β-catenin was observed. This is the first case report of an endometrial carcinosarcoma containing an SEC component. SECs of the endometrium might exhibit sex cord-like differentiation in contrast to SECs of the ovary, which do not exhibit sex cord differentiation.

Gene fusions characterize a subset of uterine cellular leiomyomas

Uterine leiomyomas are the most common benign tumor of the female genital tract. Previous studies have shown that conventional leiomyomas often harbor-specific alterations including rearrangements involving HMGA2. Cellular leiomyomas are a variant of uterine leiomyoma that are less well-studied from a genomic point of view. Morphologically and immunohistochemically, cellular leiomyomas may be confused with low-grade endometrial stromal neoplasms, a group of tumors which frequently harbor a number of recurrent gene fusions. Ancillary molecular testing may be used to investigate tumors where low-grade endometrial stromal neoplasms enter into the differential diagnosis. At our institution, we identified a uterine cellular leiomyoma harboring a HMGA2-TRAF3IP2 fusion. After a retrospective review 11 additional tumors were identified. All included cases were reviewed and evaluated for immunohistochemical expression of smooth muscle actin, desmin, h-caldesmon, CD10, estrogen receptor, and progesterone receptor. RNA sequencing using the TruSight RNA Fusion Panel was performed on formalin-fixed paraffin-embedded tissue samples. In addition to the index case, two other cases harbored fusions: HMGA2-NAA11 and TPCN2-YAP1, of which the latter is novel and was confirmed with reverse transcriptase-polymerase chain reaction. In conclusion, a subset of cellular leiomyomas harbor rearrangements involving HMGA2, suggesting molecular kinship with conventional uterine leiomyomas. In addition, the prevalence of the novel TPCN2-YAP1 gene fusion in cellular leiomyomas requires further study. The fusions reported here, when identified, may be useful when the diagnosis of cellular leiomyoma is in question.

Low-grade endometrial stromal sarcoma with a novel MEAF6-SUZ12 fusion

Endometrial stromal sarcoma (ESS) is a rare mesenchymal neoplasm. Herein, we report a low-grade ESS with a novel MEAF6-SUZ12 fusion gene. A 40-year-old woman presented with a 9.0-cm abdominal wall mass juxtaposed to the postoperative scar of surgeries for uterine "leiomyomas" and cesarean section. Histologically, mostly hypocellular and myxoid nodules were comprised of uniform spindle cells and exhibited tongue-like infiltration. Immunohistochemically, the tumor cells were positive for CD10, estrogen receptor, and CD34 (focal). There were occasional h-caldesmon-positive cohesive nests. RNA sequencing along with reverse transcriptase-polymerase chain reaction and Sanger sequencing identified an in-frame fusion of MEAF6 (exon 4) and SUZ12 (exon 2). Upon review of the previous "leiomyomas," we revised their diagnoses as low-grade ESS. The patient is alive without disease 2 years after the surgery. In addition to expanding the molecular landscape of low-grade ESS, this case highlights the challenge of diagnosing low-grade ESS in an uncommon clinicopathological setting.

Uterine sarcomas

Uterine sarcomas account for approximately 3%-7% of all uterine cancers. Since carcinosarcomas are currently classified as metaplastic carcinomas, leiomyosarcomas remain the most common subtype. Exclusion of several histologic variants of leiomyoma, as well as atypical smooth muscle tumors (so-called "smooth muscle tumors of uncertain malignant potential"), has highlighted that the vast majority of leiomyosarcomas are high-grade tumors associated with poor prognosis even when apparently confined to the uterus. Low-grade endometrial stromal sarcomas are indolent tumors associated with long-term survival. High-grade endometrial stromal sarcomas and undifferentiated endometrial sarcomas behave more aggressively than tumors showing nuclear uniformity. Adenosarcomas have a favorable prognosis except for tumors showing myometrial invasion or sarcomatous overgrowth. The prognosis for carcinosarcomas (which are considered here in a postscript fashion) is usually worse than that for grade 3 endometrial carcinomas. Tumor stage is the single most important prognostic factor for uterine sarcomas.

Extrapelvic Metastases in Endometrial Stromal Sarcomas: A Clinicopathological Review With Immunohistochemical and Molecular Characterization

Endometrial stromal sarcoma is a rare uterine tumor associated with favorable outcomes despite its ability to recur and metastasize to distant sites. Most recurrences are local, being limited to the abdomen/pelvis, but distant metastases can occur. Metastatic endometrial stromal sarcoma can occur many months to years after the original diagnosis or may present prior to the primary, potentially creating a diagnostic challenge. We report a bi-institutional review of 10 cases of endometrial stromal sarcoma with extrapelvic metastases without a prior history of endometriosis. The histologic, immunophenotypic, and molecular characteristics of these tumors are analyzed in the context of a relevant literature review.

Hepatic endometrial stromal sarcoma

Endometrial stromal sarcomas are rare tumors that may recur or metastasize many years after their initial presentation. Though most recurrences are within the pelvis, distant metastases can occur, and are most common to the lungs. Metastases to the liver are extremely rare. Herein we report two cases of endometrial stromal sarcoma with metastases to the liver without a prior history of endometriosis, accompanied by their histology, immunohistochemistry, and molecular analysis in the context of a relevant literature review.

Endometrial stromal sarcoma: a clinicopathological analysis of 14 cases

OBJECTIVE

To investigate the clinicopathologic features and immunophenotype of endometrial stromal sarcoma (ESS) and extra uterine endometrial stromal sarcoma (EESS).

METHODS

14 cases of ESS (8 cases of ESS and 6 cases of EESS) were retrospectively reviewed, and the pathological features, immunophenotype and prognosis were discussed.

RESULTS

In 14 cases of ESS, 12 cases (8 cases of ESS and 4 cases of EESS) were diagnosed as low grade endometrial stromal sarcoma (LGESS) and 2 cases of EESS were diagnosed as high grade endometrial stromal sarcoma (HGESS). Microscopically, the tumor cells in LGESS cases were composed of densely arranged endometrial stromal cells with a similar proliferative phase. They were surrounded by spiral arterioles and mitosis was rare. The tumor cells in HGESS cases displayed marked cellular atypia, increased mitosis, infiltration, and necrosis. However, small blood vessels which were common in LGESS were rarely observed in HGESS. Immunohistochemical results showed that most tumor cells were positive for CD10, vimentin, PR, and ER.

CONCLUSIONS

ESS is a rare tumor in the female genital tract and is often misdiagnosed as other mesenchymal tumors before operation. The diagnosis mainly depends on the clinicopathologic features together with the immunophenotype. LGESS has better long term survival and lower incidence of disease recurrence than HGESS. Thus, LGESS has better prognosis than HGESS.

SF1 immunohistochemistry is useful in differentiating uterine tumours resembling sex cord-stromal tumours from potential histological mimics

The aim of this study was to perform an immunohistochemical comparison of uterine tumour resembling ovarian sex cord-stromal tumour (UTROSCT) and other uterine lesions with sex cord-like (SCL) differentiation. Six UTROSCTs and 10 potential histological mimics with focal SCL elements were examined, the latter comprising three endometrial stromal nodules, three low-grade endometrial stromal sarcomas, three Müllerian adenosarcomas, and one case of adenomyosis. All cases were stained immunohistochemically for SF1, FOXL2, calretinin and inhibin, and for the less specific markers smooth muscle actin, desmin, CD10, CD56, CD99, cytokeratin, oestrogen receptor and progesterone receptor. Three, four, six and three UTROSCT expressed SF1, FOXL2, calretinin and inhibin, respectively. However, calretinin staining was focal (≤50% cells positive) in five of the cases. Three potential histological mimics demonstrated calretinin, FOXL2 and/or inhibin staining but none was SF1 positive. Most cases in both groups expressed the less specific immunomarkers. SF1 and FOXL2 immunoreactivity in UTROSCT further supports the concept that these tumours demonstrate genuine sex cord-stromal differentiation. While calretinin was the most sensitive UTROSCT marker, staining was usually focal and expression was also seen in two of 10 potential histological mimics. SF1 staining was 100% specific for UTROSCT in this series but this finding should be confirmed in larger studies.

Molecular Cytogenetic Analysis of JAZF1, PHF1, and YWHAE in Endometrial Stromal Tumors: Discovery of Genetic Complexity by Fluorescence in Situ Hybridization

Diagnosis of endometrial stromal tumors (ESTs) can be challenging, particularly endometrial stromal sarcomas (ESSs) because of variable histologic appearance, long latency to recurrence, frequent metastases with unknown primary, and overlap with endometrial stromal nodules and undifferentiated uterine sarcomas. To enhance EST diagnosis, a break-apart strategy fluorescence in situ hybridization panel to detect JAZF1, PHF1, and YWHAE rearrangements was applied to a cohort of primary or metastatic endometrial stromal nodules, ESSs, or undifferentiated uterine sarcomas (36 cases for JAZF1, 24 of which were also assessed for PHF1 and YWHAE), 24 myometrium/endometrium controls, and 37 non-ESTs in the differential diagnosis. JAZF1 was the most frequently altered gene and occurred in all EST types, JAZF1 and/or PHF1 were mutually exclusive from YWHAE involvement, and uterine and extrauterine ESTs have a shared pathogenesis. We further defined frequency of these rearrangements and provided a resource demonstrating the signal complexity that can manifest when evaluating JAZF1. Rearrangement of JAZF1 occurred in 47% of ESTs, most (70%) of which had atypical patterns representing multiple structural alterations and/or more than one clone. YWHAE and PHF1 rearrangements each occurred in 8% of ESTs. An exceptional case was an ESS without JAZF1 or MEAF6 disruption that further disputes correlation of PHF1 involvement with the sex cord-like variant. These results expand our understanding of the genetic heterogeneity that defines ESTs.

Practical issues in uterine pathology from banal to bewildering: the remarkable spectrum of smooth muscle neoplasia

Among mesenchymal tumors of the uterus, smooth muscle neoplasms are most common. The wide morphologic spectrum, especially within the category of leiomyomas, is responsible for diagnostic problems more frequently with leiomyosarcoma (including mitotically active, apoplectic, and leiomyoma with bizarre nuclei) but also with endometrial stromal tumors. In the former scenario, clinical information, gross appearance as well as strict utilization of morphologic criteria including cytologic atypia, mitotic activity, and tumor cell necrosis are clues in establishing the correct diagnosis. It is important to keep in mind that mitotic rate thresholds vary for the different subtypes of leiomyosarcoma. Of note, p16 should be used with caution in supporting a diagnosis of leiomyosarcoma as it is often positive in leiomyomas with bizarre nuclei and leiomyomas with apoplectic change (in the latter most frequently and more intense near areas of necrosis). MED12 mutations have also a very limited role in this differential diagnosis. Endometrial stromal tumors are by far, less common than smooth muscle tumors, but can be confused with leiomyosarcomas if they are associated with an undifferentiated uterine sarcoma and the low-grade component is overlooked or they have a myxoid/fibroblastic morphology. The differential diagnosis may be confounded if the latter is associated with a high-grade endometrial stromal sarcoma. It is important to highlight that CD10 is not a reliable marker in these differentials and should be used as a part of a panel of antibodies that also includes desmin and h-caldesmon. Two other recently categorized tumors in the uterus that merit special mention are PEComa and inflammatory myofibroblastic tumor as they enter in the differential diagnosis of smooth muscle tumors. PEComa may be part of the tuberous sclerosis syndrome and may show either a predominantly epithelioid or spindle morphology or combination thereof. Rarely, it may contain melanin pigment. There is variable positivity for HMB-45, MelanA, MiTF, and CathepsinK, and some tumors have been shown to express TFE-3 especially when associated with "clear cell" morphology. Patients with adverse outcome have tumors with ≥2 of the following features: ≥5 cm, infiltration, high-grade cytologic features, mitotic rate ≥1/50 high-power fields, necrosis, or lymphovascular invasion. Inflammatory myofibroblastic tumor is important to recognize as it often mimics myxoid smooth muscle tumors, either benign or malignant. The presence of an associated lymphoplasmacytic infiltrate should alert to that possibility and ALK studies (immunostain or FISH) are helpful in establishing this diagnosis. These tumors can behave in a malignant manner if large, associated with abundant myxoid change, brisk mitotic rate or show tumor cell necrosis.

Magnetic resonance imaging of an endometrial stromal nodule

Endometrial stromal nodules are rare benign tumors that appear as well-circumscribed globular masses in the myometrium. In this report, a myometrial mass exhibited heterogeneous hyperintensity without hypointense bands on T2-weighted images and homogeneous isointensity on T1-weighted images. A dynamic contrast study revealed the same degree of uterine myometrial enhancement only in the marginal area. The structures were pathologically confirmed to correspond with proliferating endometrial stromal cells. Herein, we report this rare tumor and the correlation between magnetic resonance imaging and pathological findings.

Cellular leiomyoma versus endometrial stromal tumor: A pathologists' dilemma

Uterine smooth muscle tumors and endometrial stromal tumors (ESTs) are the two major types of mesenchymal tumors of the uterus, the latter being fairly uncommon. Among these, endometrial stromal sarcoma (ESS) accounts for 0.2-1.5% of all uterine malignancies. Although routine histopathological examination is sufficient to distinguish between ESS and smooth muscle tumors in most of the cases, the distinction between ESTs and highly cellular leiomyomas (CMs), on several occasions becomes a great diagnostic challenge for the pathologist. The differentiation between EST and CM is necessary on account of the variable clinical course and slight variation in the therapy. However, this is difficult due to the tendency of endometrial stromal cells to differentiate into well-developed smooth muscle cells as well as overlapping immunohistochemical profile in some cases. We hereby report a series of cases which posed a diagnostic challenge to us as to whether they are CMs or ESTs. We therefore discuss the histological features which helped us resolve this dilemma as well as the utility of immunohistochemistry (IHC) as a diagnostic aid in arriving at a final diagnosis in such problematic cases.

Clinical experience of uterine tumors resembling ovarian sex cord tumors: a clinicopathological analysis of 6 cases

OBJECTIVE

To compare the clinicopathological features, diagnosis, treatment, and prognosis of two types of uterine sex cord-like tumors.

METHODS

The clinicopathological features of four uterine tumors resembling ovarian sex cord tumors (UTROSCTs) and two endometrial stromal tumors with sex cord-like elements (ESTSCLEs) were analyzed retrospectively.

RESULTS

All patients were premenopausal women. The most common clinical presentation was vaginal bleeding (four cases). Total hysterectomy with or without bilateral adnexectomy was the most common treatment pattern (five cases). A patient with UTROSCTs, presenting with recurrence 10 months after transvaginal submucous myomectomy, underwent a total hysterectomy (case 2). All tumors were polypoid or intramural masses, usually located in the uterine fundus or submucosa. The majority of UTROSCTs were positive for cytokeratin (4/4 cases), one was positive for Wilms tumor protein, and of two cases with smooth muscle actin immunoreactivity, two were positive for desmin. UTROSCTs were positive for two or more sex cord markers, whereas sex cord markers were less frequently detected in ESTSCLEs. CD10 was variably positive in two UTROSCT patients and strongly positive in all ESTSCLE patients. Three UTROSCTs and one ESTSCLE were positive for both estrogen and progesterone receptors. All patients with UTROSCTs were alive without evidence of recurrence. One patient with ESTSCLEs underwent postoperative chemotherapy after total vaginal hysterectomy but developed recurrence at the vaginal stump (case 5). The other patient with ESTSCLEs was lost to follow-up.

CONCLUSION

These UTROSCTs are polymorphic neoplasms with true sex cord differentiation and uncertain malignant potential, which possess a distinct biology from ESTSCLEs.

Diffusion-Weighted MRI and FDG-PET in Diagnosis of Endometrial Stromal Nodule

Preoperative differentiation of benign endometrial stromal nodule (ESN) from malignant low-grade endometrial sarcoma (LGESS) is challenging, because it requires histological evaluation of the tumor-myometrium interface, which is difficult to obtain in conventional endometrial curettage. A 72-year-old postmenopausal woman presented with 5-year history of persistent vaginal bleeding. Histological examination of the endometrial curettage specimen revealed hyperplasia of apparently normal endometrial stromal cells. T2-weighted magnetic resonance imaging (T2W-MRI) showed polypoid tumor occupying the entire uterine cavity. The tumor exhibited high signal intensity in diffusion-weighted MRI (DW-MRI) and intense accumulation of ¹⁸F-fluorodeoxyglucose (FDG) in positron emission tomography (PET). Intense FDG accumulation was also observed in the left internal iliac region. Total abdominal hysterectomy, bilateral salpingo-oophorectomy, and pelvic lymphadenectomy were performed under the diagnosis of LGESS with lymph node metastasis. However, postoperative histological examination proved that the tumor was ESN without lymph node metastasis. Since mitotic figure is no longer included in the diagnostic criteria of ESN or LGESS, ESN could exhibit high cellularity and high proliferative activity as observed in this case. Therefore, DW-MRI or FDG-PET is not useful in the differentiation of ESN from LGESS.

A prognosis based classification of undifferentiated uterine sarcomas: identification of mitotic index, hormone receptors and YWHAE-FAM22 translocation status as predictors of survival

Undifferentiated uterine sarcomas (UUS) are rare tumors with a heterologous biology and a poor prognosis. The goal of this study was to examine clinicopathology, biomarkers and YWHAE-FAM22 translocation status, in the prognosis of these tumors. Twenty-six cases of UUS were included. All original slides were rereviewed and age at diagnosis, tumor stage, "Kurihara" diagnosis, mitotic index, presence of necrosis and grade of nuclear atypia were recorded. Additionally, a tissue microarray was constructed from 22 of the cases, and the protein biomarkers P53, P16, Ki-67, Cyclin-D1, ER, PR and ANLN were evaluated by immunohistochemistry. All tumors were evaluated for the presence of a YWHAE-FAM translocation; the translocation was demonstrated in the three Cyclin-D1 positive tumors. Follow-up data in the form of overall survival were available on all patients. These tumors could be divided into two prognostic groups, a high mitotic index group (10 cases, M = 36.8, SD = 5.4) and a low mitotic index group (16 cases, M = 8.7, SD = 5.8). These two groups showed a statistically significant difference in prognosis. The expression of ER, PR or presence of the YWHAE-FAM22 translocation correlated with low mitotic index and an additionally improved prognosis, although the number of cases was small. These results indicate that UUS can be divided into two prognostic groups using mitotic index as a primary criteria, followed by expression of either ER, PR or the presence of a YWHAE-FAM22 translocation as a secondary criteria. This study demonstrates the presence of statistically significant prognostic subgroups within UUS, and provides treatment insights.

Uterine tumors resembling ovarian sex cord tumors

Uterine tumors resembling ovarian sex cord tumors (UTROSCT) are rare neoplasms of unknown etiology. Only 67 cases have been reported in the literature, to our knowledge, so far. The neoplasm usually occurs in middle-aged women. Most patients present with abnormal uterine bleeding and/or abdominal pain, along with an enlarged uterus or a palpable uterine mass. There is no specific imaging finding, and the diagnosis is made exclusively on histopathologic examination. A multitude of architectural patterns are described, which include plexiform cords, anastomosing trabeculae, watered-silk, microfollicle, macrofollicle, tubules, retiform, solid cellular islands, and diffuse pattern of growth. The neoplastic cells are usually small with round to ovoid nuclei, nuclear monotony, mild nuclear hyperchromasia, and inconspicuous nucleoli with scant eosinophilic cytoplasm. Nuclear grooves are rare. Mitotic figures are infrequent, and necrosis is mostly absent. This tumor depicts a diverse immunohistochemical profile with expression of sex cord, epithelial, and smooth muscle lineages markers. Sex cord markers, such as inhibin, calretinin, CD99, WT1, and MART-1; epithelial markers, such as pancytokeratin and epithelial membrane antigen; smooth muscle markers, such as smooth muscle actin, desmin, and histone deacetylase 8; and miscellaneous markers, such as CD10, estrogen receptor, progesterone receptor, S100, and CD117, are often coexpressed. Immunoexpression for calretinin and at least for one of the other sex cord markers is required to establish a diagnosis of UTROSCT. Hysterectomy with or without bilateral salpingo-oophorectomy is usually the treatment for UTROSCT. Although most UTROSCTs behave benignly, some do recur, and thus, this entity should be considered as a tumor of low malignant potential. In this review, we discuss the current knowledge on UTROSCT and its clinical relevance.

MEAF6/PHF1 is a recurrent gene fusion in endometrial stromal sarcoma

The chimeric transcripts described in endometrial stromal sarcomas (ESS) are JAZF1/SUZ12, YWHAE/FAM22, ZC3H7/BCOR, MBTD1/CXorf67, and recombinations of PHF1 with JAZF1, EPC1, and MEAF6. The MEAF6/PHF1 fusion had hitherto been identified in only one tumor. We present two more ESS with MEAF6/PHF1 detected by transcriptome sequencing (case 1) and RT-PCR (case 2), proving that this fusion is recurrent in ESS. The transcript of both cases was an in-frame fusion between exon 5 of MEAF6 and exon 2 of PHF1. Both genes are involved in epigenetic modification, and this may well be their main pathogenetic theme also in ESS tumorigenesis.

Low grade endometrial stromal sarcoma in a premenopausal woman

Endometrial stromal sarcoma are rare malignant tumors of the uterus and has been described as the second most common malignant uterine mesenchymal tumor. The diagnosis is confirmed on hysterectomy for a presumed benign disease. In the latest World Health Organization (WHO) classification (2003), the term endometrial stromal tumor is applied to neoplasms typically composed of cells that morphologically resemble endometrial stromal cells of the nonneoplastic proliferative phase endometrium. The WHO recognizes three categories of endometrial stromal tumors: Endometrial stromal nodule, low-grade endometrial stromal sarcomas (LGESS), and undifferentiated endometrial sarcoma. We report here an interesting case of a 39-year-old female who presented with irregular bleeding per vaginum and urinary retention with a clinical impression of a leiomyomatous polyp, which on histological examination showed a LGESS.

Diagnosis of endometrial stromal tumors: a clinicopathologic study of 25 biopsy specimens with identification of problematic areas

OBJECTIVES

To assess the difficulties associated with diagnosing endometrial stromal tumors (ESTs) on endometrial biopsy.

METHODS

We examined 25 endometrial biopsy specimens from 19 consecutive women diagnosed with either endometrial stromal nodule (n = 3) or endometrial stromal sarcoma (n = 16).

RESULTS

Rereview of the biopsy specimens revealed a stromal fragment suspicious for an EST in 16, of which eight had received a benign diagnosis on initial review. Most ESTs had an aglandular stromal fragment that was 5 mm or larger. Stromal fragments of this size were not encountered in the control material. Problematic areas included highly cellular leiomyoma and a lack of attention to the stromal compartment.

CONCLUSIONS

Most endometrial stromal tumors present with large aglandular stromal fragments (≥5 mm). These fragments are large enough that difficulties in diagnosis appear to be due to a lack of attention to the stromal compartment.

Endometrial stromal sarcoma: a systematic review

OBJECTIVE

To summarize available studies with respect to evaluation and management of patients with endometrial stromal sarcoma and undifferentiated endometrial sarcoma.

DATA SOURCES

We conducted an electronic search of research articles published in English between January 1, 1981, and January 1, 2013, using MEDLINE, PubMed, and ClinicalTrials.gov (www.clinicaltrials.gov) databases.

METHODS OF STUDY SELECTION

Of the 115 studies initially identified, 86 were chosen after limiting the review to those articles focusing on endometrial stromal sarcoma and crossreferencing to eliminate duplication. Review articles were excluded. Of the 86 studies meeting eligibility criteria, 84 were retrospective, one was a prospective phase II trial, and one was a phase III randomized study. Data were extracted systematically. Each of the reviewers assessed the quality of each study independently.

TABULATION, INTEGRATION, AND RESULTS

Data were abstracted using standard abstraction templates to summarize study findings. Given the rarity of this tumor, we report available data with respect to epidemiology, pathogenesis, prognostic factors, and treatment. Endometrial stromal sarcoma and undifferentiated endometrial sarcoma comprise an estimated 1% of all uterine cancers and less than 10% of all uterine mesenchymal neoplasms. Hysterectomy and bilateral salpingo-oophorectomy is the cornerstone of treatment for early-stage (I or II) disease. Surgical resection when feasible may also be appropriate for patients presenting with advanced-stage tumors. The value of adjuvant therapy for early-stage disease remains unproven. Hormone therapy continues to be the most efficacious treatment modality for patients with advanced-stage or recurrent disease.

CONCLUSION

Endometrial stromal sarcoma and undifferentiated endometrial sarcoma are rare tumors. Surgical resection is appropriate for patients with early-stage (I or II) disease and those with resectable, advanced-stage (III or IV) tumors. Hormone therapy may be appropriate in treating advanced and recurrent disease.

Malignant Potential of Endometrial Stromal Tumor With Limited Infiltration

Endometrial stromal tumors (ESTs) with limited infiltration were first proposed by Dionigi et al.1 However, the prognostic significance of these tumors is unclear. We report a case of a 60-year-old woman who presented with a prolapsed uterine corpus and then underwent laparoscopic-assisted vaginal hysterectomy. A very small EST was incidentally found. The tumor manifested focal irregularity and finger-like permeation into the adjacent myometrium not exceeding 3 mm but exceeding 3 in number, features intermediate between a low-grade endometrial stromal sarcoma and an endometrial stromal nodule. By definition, we rendered a descriptive diagnosis of “endometrial stromal tumor with limited infiltration.” A subsequent staging operation confirmed metastasis and, hence, a malignant potential.

Endometrial sarcomas: an immunohistochemical and JAZF1 re-arrangement study in low-grade and undifferentiated tumors

The current World Health Organization classification divides endometrial sarcomas into low-grade endometrial stromal sarcoma and undifferentiated endometrial sarcoma. Recent studies suggest undifferentiated endometrial sarcoma is a heterogeneous group and a subgroup with uniform nuclei is more akin to low-grade endometrial stromal sarcoma in terms of morphologic, immunohistochemical and genetic features. We classified endometrial sarcomas treated at our institution from 1998 to 2011 into low-grade endometrial stromal sarcoma and undifferentiated endometrial sarcoma, the latter being further categorized into a group with either uniform or pleomorphic nuclei. Morphological features, immunoprofile and fluorescence in situ hybridization rearrangements of JAZF1 and PHF1 genes were correlated with tumor category and outcome. A total of 40 cases were evaluated comprising 23 low-grade endometrial stromal sarcomas, 10 undifferentiated endometrial sarcomas with nuclear uniformity and 7 undifferentiated endometrial sarcomas with nuclear pleomorphism. Low-grade endometrial stromal sarcomas were more often estrogen and progesterone receptor positive (83%) compared with undifferentiated endometrial sarcoma with nuclear uniformity (10%) or with nuclear pleomorphism (0%) (P<0.001). Positivity for p53 was restricted to undifferentiated endometrial sarcomas with more frequent expression in the group with nuclear pleomorphism (57%) than with nuclear uniformity (10%) (P=0.06). Ki-67 proliferation index in >10% of tumor cells more frequent in undifferentiated endometrial sarcoma than low-grade endometrial stromal sarcoma (P=<0.001). JAZF1 rearrangement was detected in 32% of low-grade endometrial stromal sarcomas and in none of the undifferentiated sarcomas. Rearrangement of PHF1 was found in two patients, one with JAZF1-PHF1 fusion. There were no significant differences in clinical behavior between undifferentiated endometrial sarcoma with nuclear uniformity versus nuclear pleomorphism. In conclusion, we found undifferentiated endometrial sarcoma subtypes and low-grade endometrial stromal sarcoma have distinct immunohistochemical and cytogentic profiles. Our data do not show any difference in clinical behavior between subgroups in undifferentiated sarcomas.

Cerebral metastases of an endometrial stromal sarcoma: report of the first case

BACKGROUND

Endometrial stromal sarcomas (ESSs) of the uterus are rare gynecological malignancies. Common locations of distant metastases are vagina, vulva, lung, mediastinum, abdomen, bones and ovaries.

CASE REPORT

We present the case of a 69-year-old woman with a Federation of Gynecology and Obstetrics (FIGO) IIb (classification 2009) ESS of the uterus of high-grade malignancy. Initially, a hysterectomy Piver II and total colpectomy were performed, followed by pelvic field irradiation. 8 months later, the patient suffered seizures and hemiparesis. A computed tomography (CT) scan revealed cerebral metastases, and irradiation of the brain was initiated. After completion of the staging examinations, additional metastases of lung, abdomen, mediastinum, vulva and inguinal lymph nodes were found. This is the first reported case of brain metastases of an ESS.

CONCLUSION

Appropriate treatment options like surgery, chemotherapy or endocrine therapy should be discussed on an individual basis since large-scale clinical trials have not yet been conducted in this rare entity.

Novel fusion of MYST/Esa1-associated factor 6 and PHF1 in endometrial stromal sarcoma

Rearrangement of chromosome band 6p21 is recurrent in endometrial stromal sarcoma (ESS) and targets the PHF1 gene. So far, PHF1 was found to be the 3′ partner in the JAZF1-PHF1 and EPC1-PHF1 chimeras but since the 6p21 rearrangements involve also other chromosomal translocation partners, other PHF1-fusions seem likely. Here, we show that PHF1 is recombined with a novel fusion partner, MEAF6 from 1p34, in an ESS carrying a t(1;6)(p34;p21) translocation as the sole karyotypic anomaly. 5′-RACE, RT-PCR, and sequencing showed the presence of an MEAF6-PHF1 chimera in the tumor with exon 5 of MEAF6 being fused in-frame to exon 2 of PHF1 so that the entire PHF1 coding region becomes the 3′ terminal part of the MEAF6-PHF1 fusion. The predicted fusion protein is composed of 750 amino acids and contains the histone acetyltransferase subunit NuA4 domain of MEAF6 and the tudor, PHD zinc finger, and MTF2 domains of PHF1. Although the specific functions of the MEAF6 and PHF1 proteins and why they are targeted by a neoplasia-specific gene fusion are not directly apparent, it seems that rearrangement of genes involved in acetylation (EPC1, MEAF6) and methylation (PHF1), resulting in aberrant gene expression, is a common theme in ESS pathogenesis.

Clinicopathologic features of 2 new cases of uterine tumors resembling ovarian sex cord tumors

Uterine neoplasms showing an exclusive sex cord-like differentiation or focal low-grade sarcoma differentiation, designated as uterine tumors resembling ovarian sex cord tumors (UTROSCTs), are rare, with only 48 cases described earlier in international literature. Generally, this entity is characterized by benign behavior. In this study, we report the clinical and pathologic features of 2 peculiar new cases of UTROSCTs. In these examples, the pathologic diagnosis of UTROSCT was made incidentally after the clinical diagnosis of a leiomyoma and endometrial polyp. On examination of small biopsies, the diagnosis was facilitated by specific immunohistochemical analysis using markers for the sex cord component. In 1 of these cases, the patient, because of her young age and her desire to preserve her fertility, was only treated by minimally invasive hysteroscopic surgery. In the other case, the neoplasm seemed to be the consequence of tamoxifen treatment for breast carcinoma. After diagnosis, in this second case, the woman underwent hysterectomy that showed a residue of the tumor and cervical metastasis from the earlier breast carcinoma. The differential diagnosis of UTROSCT and the role of immunohistochemistry in confirming a diagnosis are discussed.

Endometrial stromal sarcoma located in the myometrium with a low-intensity rim on T2-weighted images: report of three cases and literature review

Endometrial stromal sarcoma (ESS) most commonly grows from the uterine endometrium into the endometrial cavity; it is rarely located in the myometrium alone, where it may resemble degenerated leiomyoma on magnetic resonance imaging (MRI). We present three cases of intramyometrial ESS mimicking degenerated leiomyoma, all of which have a characteristic low-intensity rim on T2-weighted images. Histopathological examination revealed the rim to consist of fibrous tissue layers and/or a decrease in free water caused by distortion of myometrial tissue following tumor expansion. ESS should be included in the differential diagnosis of intramyometrial mass with low-intensity rim on T2-weighted image, especially if the mass shows degeneration with no or mild intratumoral hemorrhage.

Absence of the JAZF1/SUZ12 chimeric transcript in the immortalized non-neoplastic endometrial stromal cell line T HESCs

Endometrial stromal sarcomas are rare malignancies, accounting for less than 10% of uterine sarcomas. The most characteristic chromosomal aberration of this tumor type is the translocation t(7;17)(p15-p21;q12-q21) leading to the fusion of two zinc finger genes, JAZF1 and SUZ12. Recently, the presence of the neoplastic JAZF1/SUZ12 fusion transcript was reported in normal cells of human endometrium. One of the positive samples for the JAZF1/SUZ12 transcript was the immortalized T HESCs cell line. This cell line was derived from the stromal cells obtained from an adult female with myomas and immortalized by transfection of a human telomerase gene. Since T HESCs has a normal karyotype and no fusion of the two genes occurs at the genomic level, the JAZF1/SUZ12 transcript was proposed to be generated by regulated trans-splicing between precursor RNAs for JAZF1 and SUZ12. However, no confirmatory reports currently exist. To determine whether the results could be reproduced, the T HESCs cell line was subjected to three different RT-PCR amplifications for the JAZF1/SUZ12 fusion transcript. RT-PCR assays did not amplify JUZF1/SUZ12 cDNA fragments in the T HESCs cell line, whereas the same assays easily generated JUZF1/SUZ12-amplified transcripts in an endometrial stromal cell sarcoma carrying the t(7;17) chromosomal aberration. Thus, the presence, if any, of a JUZF1/SUZ12 chimeric transcript in the immortalized normal T HESCs is not a constant, reproducible result.

Molecular profiling of endometrial malignancies

Molecular profiling of endometrial neoplasms reveals genetic changes in endometrial carcinomas that support the dualistic model, in which type I carcinomas are estrogen-dependent, low grade lesions and type II carcinomas are nonestrogen dependent and high grade. The molecular changes in type I endometrial carcinomas include mutations in PTEN, PIK3CA, KRAS, and β-catenin, along with microsatellite instability, whereas type II endometrial carcinomas are characterized by genetic alterations in p53, HER2/neu, p16, and E-cadherin. For endometrial neoplasms with a malignant mesenchymal component, C-MYC mutations and loss of heterozygosity are frequently seen in carcinosarcomas, and a fusion gene, JAZF1/JJAZ1, is distinctive for endometrial stromal sarcoma. In addition, p53 mutations may play an important role in tumorigenesis of undifferentiated endometrial sarcoma. These molecular changes can help in the diagnosis of endometrial neoplasms, as well as form the basis of molecular targeted therapy.

Endometrial stromal sarcomas: a review of potential prognostic factors

Endometrial stromal tumors are uncommon mesenchymal tumors of the uterus. The classification of these tumors has evolved and the most current World Health Organization classification (2003) divides these neoplasms into: endometrial stromal nodule, low-grade endometrial stromal sarcoma, and undifferentiated endometrial sarcoma. The salient clinicopathologic features of these tumors are described, and a comprehensive review of literature pertaining to potential prognostic factors in endometrial stromal sarcomas is provided. Clinical factors, including age, race, parity and menopausal status, and pathologic factors, including tumor size, tumor stage, nuclear atypia, mitotic activity, tumor necrosis, lymphovascular space invasion, DNA ploidy and proliferative activity, and expression of hormone receptors, have been explored with varying outcomes. Surgicopathologic stage seems to be the most important prognostic factor in low-grade endometrial stromal sarcomas. The impact of other prognostic factors on survival is unclear or controversial, especially in patients with stage I tumors.

Endometrial/ioid Stromal Tumors and Related Neoplasms of the Female Genital Tract

Endometrial/ioid stromal tumors comprise a spectrum of mesenchymal neoplasms, ranging from benign to low-grade malignancy to undifferentiated sarcomas, which occur predominantly in the uterus but may rarely originate at extrauterine sites, most commonly in the ovary. These tumors and their morphologic variants are important to recognize as they often cause diagnostic difficulties. This review focuses on the diagnostic criteria and differential diagnosis, including the role of immunohistochemistry.

Uterine sarcomas: a review

OBJECTIVE

Uterine sarcomas are rare tumors that account for 3% of uterine cancers. Their histopathologic classification was revised by the World Health Organization (WHO) in 2003. A new staging system has been recently designed by the International Federation of Gynecology and Obstetrics (FIGO). Currently, there is no consensus on risk factors for adverse outcome. This review summarizes the available clinicopathological data on uterine sarcomas classified by the WHO diagnostic criteria.

METHODS

Medline was searched between 1976 and 2009 for all publications in English where the studied population included women diagnosed of uterine sarcomas.

RESULTS

Since carcinosarcomas (malignant mixed mesodermal tumors or MMMT) are currently classified as metaplastic carcinomas, leiomyosarcomas remain the most common uterine sarcomas. Exclusion of several histologic variants of leiomyoma, as well as "smooth muscle tumors of uncertain malignant potential," frequently misdiagnosed as sarcomas, has made apparent that leiomyosarcomas are associated with poor prognosis even when seemingly confined to the uterus. Endometrial stromal sarcomas are indolent tumors associated with long-term survival. Undifferentiated endometrial sarcomas exhibiting nuclear pleomorphism behave more aggressively than tumors showing nuclear uniformity. Adenosarcomas have a favorable prognosis except for tumors showing myometrial invasion or sarcomatous overgrowth. Adenofibromas may represent well-differentiated adenosarcomas. The prognosis of carcinosarcomas (which are considered here in a post-script fashion) is usually worse than that of grade 3 endometrial carcinomas. Immunohistochemical expression of Ki67, p53, and p16 is significantly higher in leiomyosarcomas and undifferentiated endometrial sarcomas than in endometrial stromal sarcomas.

CONCLUSIONS

Evaluation of H&E stained sections has been equivocal in the prediction of behavior of uterine sarcomas. Immunohistochemical studies of oncoproteins as well as molecular analysis of non-random translocations will undoubtedly lead to an accurate and prognostically relevant classification of these rare tumors.

[Mesenchymal uterine tumors. Stromal tumors and other rare mesenchymal neoplasms]

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).

Low-Grade Endometrial Stromal Sarcoma and Undifferentiated Endometrial Sarcoma: A Comparative Analysis Emphasizing the Importance of Distinguishing Between These Two Groups

Endometrial stromal sarcomas (ESSs) are rare tumors whose classification is still controversial. In this study, the authors studied 19 patients diagnosed with ESS at the Hospital S João, Porto, Portugal; reviewed their files and material; and performed immunohistochemical study for CD10, desmin, and smooth muscle actin markers, aiming to compare low-grade endometrial stromal sarcomas (LG-ESSs) and undifferentiated endometrial sarcomas (UESs) using the World Health Organization (WHO) classification. Twelve cases (63%) were classified as LG-ESS and 7 (37%) as UES. The median age at diagnosis was 49 years, and women with LG-ESS tended to be younger than those with UES. Most cases (7/11) had a previous echographic diagnosis of leiomyoma. A biopsy or curettage was performed in 6 cases, providing a definitive diagnosis of malignancy in 4. Frozen section was performed in 4 patients. The majority (63%) of patients were FIGO stage I. Twelve (63%) cases showed diffuse or focal expression of CD10. Desmin and smooth muscle actin expression was focal in 4 (21%) tumors. Patients with LG-ESS had a significant better overall survival than those with UES ( P = .026). Mitotic count had no prognostic significance. Our data emphasize the clinical importance of the WHO classification in ESS. It is of utmost importance to establish a proper classification to increase the consistency of data that may be useful for improving clinical and therapeutic management of patients with ESS.

A case of primary retroperitoneal undifferentiated endometrial stromal sarcoma after concurrent chemoradiation therapy for cervical cancer

Endometrial stromal sarcoma (ESS) is a relatively rare uterine sarcoma, especially extrauterine ESS. Furthermore, retroperitoneal ESS are extremely rare. Up to now, there are only four cases of primary retroperitoneal ESS reported in the literature. We report one case of primary retroperitoneal undifferentiated endometrial stromal sarcoma after concurrent chemoradiation therapy for cervical cancer with a brief review of the literature.

An endometrial stromal sarcoma cell line with the JAZF1/PHF1 chimera

Endometrial stromal sarcomas (ESS) are rare malignancies, accounting for less than 10% of uterine sarcomas. Apart from the chromosomal rearrangement t(7;17)(p15;q21), which leads to the JAZF1/SUZ12 chimera, cytogenetic studies have shown that the chromosome band 6p21 is often rearranged in ESS. The translocation partners involved in the 6p21 rearrangements differ among the tumors, but chromosome 7 is involved in most aberrations. A JAZF1/PHF1 fusion gene was recently found in two tumors showing an exchange between 6p and 7p rearrangement. In the present study, we show that a low-grade ESS cell line carrying a der(7)t(6;7)(p21;p22) also harbors the a JAZF1/PHF1 fusion. In the fusion transcript, exon 3 of JAZF1 was fused with exon 2 of PHF1. At the junction, there was an insertion of 26 nucleotides, originating from intron 3 of JAZF1, thus maintaining an open reading frame of the chimeric transcript. The predicted 684-amino acid JAZF1/PHF1 chimeric protein retained one zinc finger domain from JAZF1 and the two zinc finger domains from PHF1, and its oncogenic mechanism should be similar to that of the JAZF1/SUZ12 protein. The present cell line constitutes an excellent model for further studies on the impact of the JAZF1/PHF1 fusion.

Immunohistochemical profiling of cytokeratin expression by endometrial stroma sarcoma

Endometrial stromal sarcomas can be confused with several neoplasms because of their inconsistent and widely varied morphologic appearance and frequent immunohistochemical expression of a variety of antigens including cytokeratin. The resulting diagnostic challenge becomes problematic particularly in the diagnosis of metastases resulting from such tumors. Because of the sometime epithelioid appearance of the tumor cells and their expression of cytokeratin, the metastases may be misdiagnosed as poorly differentiated carcinoma. We therefore studied the profile of cytokeratin proteins expression in 17 cases of endometrial stromal sarcomas using a panel of antibodies including cytokeratin cocktail antibody (AE1/AE 3), CK5/6, CK7, CK14, CK16, Cam5.2 (CK8), CK19, CK20, and 34Ebeta12 (CK1, 5, 10, and 14). Of the 17 cases, 8 (47%) stained positive with the cytokeratin cocktail antibody (AE1/AE 3). Of the 8 cases with cytokeratin expression, 5 (63%) stained positive with CK19, and 3 of them stained positive with Cam5.2. The 3 cases that stained positive with Cam5.2 also expressed CK19. Of the 5 cases with CK19, 1 was focally positive for CK5/6, CK7, and 34Ebeta12. None of the cases expressed CK14, CK16, or CK20. These results show that CK19 is most commonly expressed cytokeratin in endometrial stromal tumors. Hence, the inclusion of CK19 in the panel of immunostains may help resolve the diagnostic confusion created by keratin expression in endometrial stromal sarcoma and may also help in the correct diagnosis of endometrial stromal sarcoma at extrauterine sites.