Search

Endometrial stromal tumors (ESTs) are uncommon uterine mesenchymal lesions. Nuclear expression of β-catenin, an indication of activated Wnt/β-catenin signaling pathway, was described in 50% to 92% of low-grade ESTs, including endometrial stromal nodule and low-grade endometrial stromal sarcoma. Activation of the Wnt/β-catenin signaling pathway leads to the translocation of β-catenin into the nucleus and interaction with the T-cell factor/lymphoid enhancer-binding factor-1 (LEF1) family of transcription factors to regulate cell proliferation, differentiation, migration, and survival. Immunohistochemical analysis of β-catenin and LEF1 was performed in 2 endometrial stromal nodules and 20 low-grade endometrial stromal sarcomas and demonstrated 90.9% and 81.8% positive rates for β-catenin and LEF1, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of β-catenin and LEF1 were 90.9% versus 81.8%, 81.0% versus 85.7%, 83.3% versus 85.7%, 89.5% versus 81.8%, respectively, in the diagnosis of low-grade ESTs. There is no statistical significance of the performance of β-catenin and LEF1 in all ESTs ( P = 0.664) or in primary or metastatic/recurrent settings ( P = 0.515 and 0.999, respectively). Only 3 smooth muscle tumors showed focal and weak positivity for LEF1. Our results indicate LEF1 can be a useful marker in aiding a diagnosis of low-grade EST and differentiating from smooth muscle tumors alone or in combination with β-catenin., Competing Interests: The authors declare no conflict of interest., (Copyright © 2023 by the International Society of Gynecological Pathologists.)

Background: Endometrial stromal tumors (ESTs) are rare subset of mesenchymal uterine neoplasms. There are heterogeneous morphological, immunohistochemical, and genetic features. Approximately 50% of ESTs occur in perimenopausal women. In 2020, WHO sub-categorized ESTs into four groups: endometrial stromal nodule (ESN), low-grade endometrial stromal sarcoma (LGESS), high-grade endometrial stromal sarcoma (HGESS), and undifferentiated uterine sarcoma (UUS)., Objective: To review the morphological spectrum of endometrial stromal tumors., Method: This retrospective study reviewed the histomorphological features of 15 endometrial stromal tumors with respect to atypia, necrosis, mitosis, collagen bands, whorling around vessels, myometrial invasion, and inflammatory cells. Immunohistochemistry markers (CD10, SMA, and ER) along with special stains (Masson's trichrome, toluidine blue) were also studied., Results: The age of the patients ranged from 32 to 60 years. Three patients were postmenopausal. The most common presenting symptom was vaginal bleeding. Five patients were operated with a clinical diagnosis of uterine fibroid. One patient presented with prolapse with no other complaint. All the 15 patients had total abdominal hysterectomy and salpingo-oophorectomy. One case showed necrosis, eight cases showed collagen bands, all the 15 cases showed whorling around vessels, one case showed vascular emboli, and seven cases showed inflammatory cells. In low-grade cases, one case showed focal atypia and one case showed focal coagulative necrosis indicating infarction. Thirteen cases were LGESS, and one case of ESN and HGESS. All cases were positive for ER and CD10., Conclusion: Endometrial stromal tumors demonstrate extensive permeation of the myometrium as irregular islands with frequent vascular invasion, whorling around vessels, collagen bands, and inflammatory cells. All these features should be observed thoroughly on microscopy by pathologists to clearly differentiate the low-grade and high-grade endometrial stromal tumors, and to understand the overlapping gray areas morphologically as it affects the prognosis of the patient., (Copyright © 2023 Copyright: © 2023 Journal of Cancer Research and Therapeutics.)

Endometrial stromal tumors represent the second most common category of uterine mesenchymal tumors. Several different histologic variants and underlying genetic alterations have been recognized, one such being a group associated with BCORL1 rearrangements. They are usually high-grade endometrial stromal sarcomas, often associated with prominent myxoid background and aggressive behavior. Here, we report an unusual endometrial stromal neoplasm with JAZF1-BCORL1 rearrangement and briefly review the literature. The neoplasm formed a well-circumscribed uterine mass in a 50-yr-old woman and had an unusual morphologic appearance that did not warrant a high-grade categorization. It was characterized by a predominant population of epithelioid cells with clear to focally eosinophilic cytoplasm growing in interanastomosing cords and trabeculae set in a hyalinized stroma as well as nested and fascicular growths imparting focal resemblance to a uterine tumor resembling ovarian sex-cord tumor, PEComa, and a smooth muscle neoplasm. A minor storiform growth of spindle cells reminiscent of the fibroblastic variant of low-grade endometrial stromal sarcoma was also noted but conventional areas of low-grade endometrial stromal neoplasm were not identified. This case expands the spectrum of morphologic features seen in endometrial stromal tumors, especially when associated with a BCORL1 fusion and highlights the utility of immunohistochemical and molecular techniques in the diagnosis of these tumors, not all of which are high grade., Competing Interests: The authors declare no conflict of interest., (Copyright © 2023 by the International Society of Gynecological Pathologists.)

High-grade endometrial stromal sarcomas with ZC3H7B-BCOR fusion are rare. They are predominantly located in the endomyometrium, with morphologic features characterized as haphazardly arranged fascicles of spindle cells with mild to moderate atypia, abundant myxoid matrix, high mitotic index, and tongue-like/pushing patterns of myometrial invasion. Furthermore, conventional or variant low-grade endometrial stromal sarcomas are often not present. Clinically, they present at a higher stage and are associated with worse prognosis compared with low-grade endometrial stromal sarcoma. Given the limited number of reported cases, we describe the case of a ZC3H7B-BCOR fusion high-grade endometrial stromal sarcoma initially diagnosed on the hysterectomy specimen as low-grade endometrial stromal sarcoma based on an endometrial stromal tumor showing tongue-like myometrial and lymphovascular invasion, minimal cytologic atypia, low-mitotic activity (0-1/10 high-power field), round/spindle cell component and immunohistochemical stain results (positive for CD10, estrogen receptor, progesterone receptor, and focally positive for cyclin D1). At the time of pathologic diagnosis, she was Stage Ia and managed conservatively. Subsequent molecular analysis revealed a ZC3H7B (exon 10)- BCOR (BCL-6 corepressor) (exon 7) gene fusion. On follow-up, she showed no evidence of disease at 37 months from the time of diagnosis. This case report expands the morphologic spectrum of ZC3H7B-BCOR fusion high-grade ESS, which includes an intramural location, morphologic and immunophenotypic features similar to LG-ESS, as well as the presence of round and spindle cell components. This case also underscores the value of molecular analysis in the proper classification of ESS., Competing Interests: The authors declare no conflict of interest., (Copyright © 2023 by the International Society of Gynecological Pathologists.)

The distinction of mesenchymal tumors of the uterus is a frequent diagnostic challenge in gynecologic pathology. Especially, distinguishing low-grade endometrial stromal sarcoma (ESS) from leiomyoma or distinguishing low-grade ESS from high-grade ESS can be difficult. Epithelial-mesenchymal transition (EMT) is a physiological and pathological process in which epithelial cells lose their morphological features, become elongated and acquire mesenchymal traits. The signaling pathway of Zinc finger E-box binding homeobox 1 (ZEB1) is one of the most significant pathways involved in the EMT process and it has a crucial role in cancer progression, metastasis, and therapy resistance. We studied a series of 69 uterine mesenchymal neoplasms including 18 endometrial stromal sarcomas (10 cases of low grade and 8 cases of high grade endometrial stromal sarcomas), 26 leiomyosarcomas (8 cases of grade 1 and 19 cases of grade 2-3 leiomyosarcomas), 15 leiomyomas, and 10 rhabdomyosarcomas, using an antibody ZEB1. We graded the leiomyosarcomas depending on the FNCLCC grading system. It was observed that leiomyosarcoma was more intensely stained with ZEB1 than leiomyoma (P < 0.001) and high-grade ESS was significantly more intensely stained with ZEB1 protein than low-grade ESS (P < 0.004). It also was observed that high-grade leiomyosarcoma was significantly more intensely stained with ZEB1 protein than low-grade leiomyosarcoma (P < 0.000). Our data suggest that Zeb1 can be used to differentiate high-grade sarcomas from their low-grade counterparts as well as benign and malignant smooth muscle tumors of the uterus.

Background: Endometrial stromal tumours are uncommon tumours of the uterus. They mainly occur in perimenopausal women. Tumours with typical clinicopathological features do not usually pose diagnostic problems. However, rare clinicopathological features can occur, and clinicians without significant experience may have difficulty diagnosing these tumours and managing these patients., Methods: Herein, we report a case of endometrial stromal sarcoma that occurred in a 25-year-old woman. The pathological features, immunophenotype, treatment and prognosis were discussed., Results: The tumour revealed morphological heterogeneity, and there were similar proliferative-type endometrial stromal cells, an extensive amount of mature adipose tissue, and prominent rhabdomyoblastic and smooth muscle cells. Histopathological and immunohistochemical studies confirmed low-grade endometrial stromal sarcoma with smooth muscle, adipocytic and rhabdomyoblastic differentiation (approximately 60% were differentiated tissues). The final treatment of the tumour was total abdominal hysterectomy with bilateral salpingo-oophorectomy. There was no evidence of recurrence for 109 months postoperatively., Conclusions: We found that low-grade endometrial stromal tumours with extensive adipocytic and prominent rhabdomyoblastic differentiation are misdiagnosed because they are infrequent. They must be differentiated from rhabdomyosarcoma with accurate identification of adipocytes, and long-term follow-up is needed., (© 2022 The Authors. Journal of Clinical Laboratory Analysis published by Wiley Periodicals LLC.)

Competing Interests: The authors declare no conflict of interest.

Uterine sarcomas are a heterogeneous group of rare malignancies. Mostly (40-50%), they are leiomyosarcomas, followed by endometrial stromal sarcomas (ESS), low-grade (LG) and high-grade (HG), as well as undifferentiated sarcoma of the uterus (UUS) and adenosarcomas (AS). Other, non-organ-specific tumours such as NTRK-rearranged spindle cell neoplasia, perivascular epithelioid cell tumour (PEComa) and inflammatory myofibroblastic tumour (IMT) are extremely difficult to differentiate.In the most recent WHO classification, endometrial stromal tumours are subdivided as follows: benign, expansively growing endometrial stromal nodule (ESN) with sharp demarcation, the histologically similar-looking LG-ESS with infiltrative growth, the highly malignant HG-ESS and, as a diagnosis of exclusion, the highly aggressive UUS lacking specific lines of differentiation. LG-ESS can be differentiated from HG-ESS in most cases histomorphologically and immunohistochemically, but molecular investigations are necessary in individual cases. HG-ESS can be divided into 4 subtypes (YWHAE/NUTM2 fusion low-grade component, YWHAE/NUTM2 fusion high-grade component, ZC3H7B-BCOR fusion or BCOR-ITD) on the basis of molecular findings. Prognostically unfavourable factors in AS are severe sarcomatous overgrowth, deep myometrial invasion, high-grade histology and lymphatic vessel invasion. Tumours with NTRK fusion are immunohistochemically positive for S100 and TRK. PEComas express cathepsin K and HMB45, as well as TFE3 when translocation is present. Almost every IMT shows an alteration in the ALK gene In the case of overlapping morphology and simultaneous therapeutic and prognostic relevance, it is becoming increasingly important to verify or confirm the suspected histomorphological diagnosis by immunohistochemical and possibly molecular investigations., (© 2022. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

The molecular knowledge of endometrial stromal neoplasms has been rapidly increasing and is considered complementary to morphologic and immunohistochemical findings for better categorization of these tumors. The most common molecular alteration observed in low-grade endometrial stromal sarcomas is the JAZF1-SUZ12 fusion, whereas, low-grade endometrial stromal sarcoma with sex cord-like differentiation have been shown more commonly to have fusions involving PHF1. Herein, we present a low-grade endometrial stromal sarcoma with sex cord-like differentiation with a fluorescence in situ hybridization showing the apparent loss of one copy of JAZF1 5' and 3' signals, rather than the expected "break-apart" pattern seen in the setting of a JAZF1 fusion. The case was then further evaluated by chromosome microarray and RNA fusion analysis. Overall, the molecular findings supported a PHF1-JAZF1 fusion with deletions right before and after the JAZF1 locus, impairing probe binding and resulting in the unusual "deletion" pattern observed in the JAZF1 fluorescence in situ hybridization, which would not intuitively suggest a fusion involving JAZF1. This case illustrates the importance of integration of morphological and molecular findings as well as the limitations of fluorescence in situ hybridization in detecting fusions, particularly in the setting of more complex chromosomal alterations even though the fusion partners are well-known., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 by the International Society of Gynecological Pathologists.)

Endometrial stromal tumors are rare uterine mesenchymal tumors of endometrial stromal origin. They are classified into endometrial stromal nodule, low-grade endometrial stromal sarcoma, high-grade endometrial stromal sarcoma, and undifferentiated uterine sarcoma by the current (2020) WHO classification. Correct diagnosis of endometrial stromal tumors is critical for proper patient management. However, due to infrequent encounters, overlapping morphological features and immunohistochemical profiles, the differential diagnoses among endometrial stromal lesions and their morphologic mimics are often challenging. Partially with our own experience, here we review and summarize the tumor morphology, immunohistochemical phenotype, as well as molecular feature of endometrial stromal tumors and key differential diagnoses, emphasizing the newest developments and their utilization in daily practice., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Aims: JAZF1 translocation is the most common genetic change in low-grade (LG) endometrial stromal sarcoma (ESS), and YWHAE and BCOR translocations are common in high-grade (HG) ESS. Primary extrauterine ESS is rare, and there are limited data on molecular alterations in these tumours., Methods and Results: Cases of primary extrauterine ESS, comprising eight LG-ESS cases and five HG-ESS cases were collected. Haematoxylin and eosin and immunohistochemical staining were used to observe the histomorphology and analyse related protein expression. JAZF1, YWHAE and BCOR rearrangements were explored with fluorescence in-situ hybridisation (FISH). In LG-ESS, the tumour cells resembled normal proliferative-phase endometrial stromal cells; CD10, oestrogen receptor and progesterone receptor were expressed in all eight cases. In HG-ESS, the tumour cells had uniform HG round and/or spindle morphology, sometimes with an LG component; CD10 was fully expressed in one case and focally expressed in four cases; BCOR was expressed in all five cases, and cyclin D1 in four of five cases. FISH analysis showed JAZF1 translocation in one of eight LG-ESS cases (12.5%). YWHAE translocation occurred in four of five HG-ESS cases, with a positivity rate of 80%. BCOR translocation was absent in all five cases., Conclusions: In extrauterine LG-ESS, the rate of JAZF1 rearrangement was significantly lower than in uterine LG-ESS. This result limited the value of JAZF1 translocation for diagnosis. YWHAE rearrangement is a common genetic change in extrauterine HG-ESS. Further studies are required to confirm these findings, especially in LG-ESS., (© 2021 John Wiley & Sons Ltd.)

Background: The differential diagnosis of endometrial stromal tumor (EST) and uterine cellular leiomyoma (CL) remains a challenge in clinical practice, especially low grade endometrial stromal sarcoma (ESS) and CL, suggesting the need for novel immunomarkers panels for differential diagnosis. Interferon-induced transmembrane protein 1 (IFITM1) is a novel immunomarker for endometrial stromal cells, h-caldesmon is an immunomarker for smooth muscle cells and has a higher specificity than smooth muscle actin (SMA). So this study aimed to evaluate whether IFITM1, cluster of differentiation 10(CD10), SMA, and h-caldesmon are useful biomarker combinations for the differential diagnosis of EST and CL., Methods: Tissue microarrays were used to detect IFITM1, CD10, SMA, and h-caldesmon immunohistochemical staining in 30 EST and 33 CL cases., Results: The expressions of IFITM1 and CD10 were high in EST (86.7 and 63.3%, respectively) but low in CL (18.2 and 21.2%), whereas those of h-caldesmon and SMA were high in CL (87.9 and 100%) and low in EST (6.9 and 40%). In diagnosing EST, IFITM1 shows better sensitivity and specificity (86.7 and 81.8%, respectively) than CD10 (63.3 and 78.8%). The specificity of h-caldesmon in diagnosing CL was significantly higher (93.1%) than that of SMA (60%). When all four antibodies were combined for the differential diagnosis, the area-under-the-curve (AUC) predictive value was 0.995. The best combination for diagnosing EST was IFITM1 (+) or CD10 (+) and h-caldesmon (-) (sensitivity 86.7%, specificity 93.9%)., Conclusion: The best combination for diagnosing CL were h-caldesmon (+) and SMA (+) (sensitivity 87.9%, specificity 100%). IFITM1, CD10, SMA, and h-caldesmon are a good combination for the differential diagnosis of EST and CL., (© 2021. The Author(s).)

Endometrial stromal sarcoma (ESS) is a malignant tumor of the uterus that has been described as the second most common malignant uterine mesenchymal tumor. Primary extrauterine ESS (EESS) is an extremely uncommon occurrence. We hereby report a new bona fide case of low-grade EESS in a 74-yr-old woman arising in the vagina, presenting as a polypoid mass associated with irregular vaginal bleeding. On examination, a 6×2×2 cm polypoid mass was found in the left vaginal wall. Consequently, the patient underwent partial vaginectomy and repair. No ESS or endometriotic lesion was found in the endometrium and bilateral adnexa. The diagnosis of ESS performed by typical pathologic and immunohistochemical evaluation was as follows: beta-catenin (+++), estrogen receptor (+++), progesterone receptor (++), vimentin (++), and uniformly negative for CD10, EMA, CD31, CD34, CD117,CD99, SMA, desmin, h-caldesmon, S-100, MelanA, and HMB45. She has remained disease free with no signs or symptoms of recurrent or advanced disease for 46 mo. Although CD10 is the most useful immunohistochemical marker for the diagnosis of this tumor, negative CD10 staining can be encountered with underfixation. Therefore, it is important to use a panel of immunostains that includes CD10, beta-catenin, and smooth muscle markers. The present study describes the clinical and pathologic features of low-grade EESS through a case report and literature review. To the best of our knowledge, this is the eighth report of EESS arising from the vagina.

Within the last decade, molecular advances have provided insights into the genetics of several ovarian sex cord-stromal tumours that have otherwise been enigmatic. Chief among these advances are the identification of FOXL2, DICER1 and CTNNB1 mutations in adult granulosa cell tumours, Sertoli-Leydig cell tumours (SLCTs), and microcystic stromal tumours (MCSTs), respectively. As access to molecular diagnostic laboratories continues to become more widely available, the potential roles for tumour mutation testing in the pathological diagnosis of these tumours merit discussion. Furthermore, links to inherited cancer susceptibility syndromes may exist for some women with SLCT (DICER1 syndrome) and MCST [familial adenomatous polyposis (FAP)]. This review will address practical issues in deciding when and how to apply mutation testing in the diagnosis of these three sex cord-stromal tumours. The pathologist's role in recommending referral for formal risk assessment for DICER1 syndrome and FAP will also be discussed., (© 2019 John Wiley & Sons Ltd.)

Low grade endometrial stromal sarcoma (LGESS) is a rare neoplasm that typically arises in the uterine corpus and accounts for less than 1% of uterine sarcomas. Infrequently, extra-uterine LGESS can occur. Histologically, LGESS is characterized by a monotonous population of cells that resemble the proliferative phase of endometrial stroma and in their classic form they exhibit tongue-like growth pattern of infiltration and/or lymphovascular invasion. Infrequently LGESS can demonstrate various morphologic differentiation patterns, including endometrioid-type glands. We report the first fine needle aspiration (FNA) case of a periduodenal mass that was incidentally discovered on Computed Tomography (CT) scan of a 60-year-old female. The cytomorphologic and histologic findings and the immunohistochemical staining were consistent with a LGESS with endometrioid glandular differentiation. We are presenting the correlation between the cytologic, radiologic and pathologic features., (Copyright © 2018. Published by Elsevier Inc.)

Low-grade endometrial stromal sarcoma (LGESS) is the second most common malignant mesenchymal tumor of the uterus. The most common location is the uterine corpus, but it can also primarily arise in a variety of extrauterine locations such as pelvis, ovary, abdominal cavity, vagina, and vulva. We are reporting a case of a 47-year-old female with no significant medical history who presented with multiple pulmonary nodules. Fine needle aspiration (FNA) specimen revealed spindle cell neoplasm consistent with the diagnosis of LGESS. The differential diagnosis included neuroendocrine tumor, synovial sarcoma, solitary fibrous tumor, smooth muscle tumors, and peripheral nerve sheath tumors. The clinical, cytological, and histopathologic details of this case, as well as a discussion of the potential pitfalls and differential diagnosis of spindle cell lesions of the lung are described., (Copyright © 2018 Elsevier Inc. All rights reserved.)

We highlight a rare variant pattern of low-grade endometrial stromal sarcoma showing extensive collagenous rosette formation, closely mimicking low-grade fibromyxoid sarcoma. Additionally, this neoplasm showed diffuse and strong expression of muscle markers, favoring an initial diagnosis of leiomyosarcoma. Reverse transcription-polymerase chain reaction showed the presence of JAZF1-SUZ12 fusion transcripts, and this highlights the broad morphologic and immunophenotypic spectrum of endometrial stromal sarcoma.

Distinguishing between uterine neoplasms of smooth muscle and endometrial stromal origin is a frequent diagnostic challenge. We investigated the staining pattern of interferon-induced transmembrane protein-1 (IFITM1), a novel endometrial stromal marker, in endometrial and smooth muscle uterine neoplasms and compared it with CD10 in its ability to differentiate between these two groups. Immunohistochemistry for IFITM1 and CD10 was performed in 20 cases of smooth muscle neoplasms (10 cases leiomyoma, 10 cases leiomyosarcoma), 14 cases of endometrial stromal sarcoma (ESS) (12 cases of low grade and 2 cases of high grade) and 12 cases of carcinosarcoma. Staining was scored in terms of intensity and distribution (0=absent, 1=weak/<50%, 2=moderate/50%-75%, 3=strong/>75%). A total score was obtained by adding intensity and distribution scores and classified as positive (score 3-6) or negative (score 0-2). IFITM1 was positive in 10 of 12 (83%) low-grade ESSs, 6 of 20 (30%) smooth muscle tumors (leiomyomas and leiomyosarcomas) and 11 of 12 carcinosarcomas (91.6%). The 2 cases of high-grade ESS were IFITM1 negative. While both IFITM1 (83%) and CD10 (91%) had high sensitivity in differentiating low-grade ESSs from smooth muscle neoplasms, IFITM1 (70%) had higher specificity compared with CD10 (45%). In this study IFITM1 appears to be a more specific marker of endometrial stromal differentiation compared with CD10 in differentiating low-grade ESSs from smooth muscle neoplasms. Thus, IFITM1 may be a valuable tool as part of an immunohistochemical evaluation panel in this diagnostic scenario.

Endometrial stromal tumor with sex cord-like elements (ESTSCLE) is a rare entity that shares similar histological features with uterine tumors resembling ovarian sex cord tumors (UTROSCT). Differentiating the 2 entities involves ample sampling of the tissue to distinguish the percentage of sex cord components within the tissue, genetic studies, and immunohistochemical staining. Frozen section provides limited information for exclusion of either tumor; and the tumor is rare enough that the diagnosis may not be considered with the limited sampling; therefore, deferral of diagnosis to permanent sections may be appropriate.

Context: - Low-grade endometrial stromal sarcomas, when uterine in location, are relatively easy to diagnose because of characteristic morphology and patterns of myometrial invasion. However, when they occur at extrauterine sites, they fall under the broad umbrella of small round blue cell tumors, making diagnosis challenging, especially when they have variant morphologic features and lack the characteristic pattern of invasion., Objectives: - To provide an insight into the sites of occurrence of low-grade endometrioid stromal sarcomas, the variant morphologic patterns, clues to diagnosis, and the usefulness of immunohistochemistry as an aid to facilitate correct diagnosis. The outcome of these tumors, in comparison with their uterine counterpart, is also discussed., Data Sources: - Existing peer-reviewed literature was reviewed., Conclusions: - Low-grade endometrioid stromal sarcoma is an uncommon neoplasm that can be misdiagnosed because of its rarity, unusual location, and presence of numerous variant histologic patterns that mimic other tumors. Knowledge of those features; consideration of this tumor in the differential diagnosis of small, round blue cell tumors at any location in a woman; and an appropriate use of immunohistochemistry can help facilitate the diagnosis.

Placental neoplasms involving the fetal membranes are exceptionally rare. In leiomyomas and endometrial stromal neoplasms, a uterine origin for nodules in the membranes is also a possibility. We present a case of an incidental endometrial stromal nodule found in the decidua of the free membranes and review the literature.

Rationale: Endometrial stromal nodule (ESN) is a rare benign endometrial stroma tumor.Experiences are helpful for avoiding and treating similar postoperative complications (cervical adhesions and atresia)., Patient Concerns: When appearing in the cervical, this tumor can easily lead to complications after the surgical resection. The diagnosis and postsurgery complication of a young woman's ESN was reported here., Diagnoses: The postoperative pathological diagnosis was ESN., Interventions: A 29-year-old young woman was diagnosed and treated for ESN in cervical parts with postsurgery complications of cervical complex adhesion atresia., Outcomes: The complication was complex cervix adhesion atresia with very special imaging performance-the cervix and the palace imaged as "Twisted and Angled Staircase." This particular cervix adhesion was challenging for operation. We achieved a successful treatment through the carefully designed surgical procedure including the application of hysteroscopy and laparoscopy., Lessons: The lower uterine segment and cervix should be paid attention during suturing in this situation. Close and positive follow-ups should be planned after the endometrial stromal resection. The reconstruction of the tunnel is a solution for the problem of menstruation.

Objective: To investigate the role of JAZF1 gene rearrangement in the diagnosis and differential diagnosis of endometrial stromal sarcomas by fluorescence in situ hybridization (FISH). Methods: JAZF1 gene rearrangement was analyzed by FISH in 129 cases of ESS diagnosed from January 2008 to December 2016 including 105 cases of low-grade endometrial stromal sarcoma (LG-ESS), 21 cases of high-grade endometrial stromal sarcoma (HG-ESS) and 3 cases of undifferentiated uterine sarcoma (UUS). Sixteen cases of the related tumours in uterus were also collected as control group. The results were compared with our previous studies of JAZF1/JJAZ1 fusion gene in ESS by RT-PCR. Results: Detection of JAZF1 gene rearrangement by FISH was successfully analyzed in 144 cases. JAZF1 gene alteration was detected in 63 cases, all of which were LG-ESS, with an overall positivity of 60.6% (63/104), while no JAZF1 gene rearrangement was found in all other cases. JAZF1 gene rearrangement was present in LG-ESS with classic histology (69.3%, 52/75), smooth muscle differentiation (2/10), sex cord-like differentiation (4/5), fibromyxoid change (1/5), clear cell change (0/1), skeletal muscle differentiation (0/1), and schwannoma-like palisading pattern (0/1). The different components in all the cases of LG-ESS with variant histology had the clonal origin, with or without JAZF1 gene alteration. Compared to the results of JAZF1/JJAZ1 fusion gene by RT-PCR, the positive rate of JAZF1 gene rearrangement in LG-ESS by FISH (61.9%, 26/42) was significantly higher than that of RT-PCR (30.0%, 12/40; P <0.01). Conclusions: JAZF1 gene rearrangement is present only in LG-ESS, but not in HG-ESS, UUS or other related tumours in uterus. The frequency of JAZF1 gene rearrangement varies between classic LG-ESS and different morphologic variants. It is frequently, but not consistently, present in classic LG-ESS and less often positive in variant cases. The results of JAZF1 gene alterations in LG-ESS with different morphologic variants support the contention that the endometrial stromal and their variant morphologic components have the same clonal origin. Detection of JAZF1 gene rearrangement by FISH is very useful for the diagnosis and differential diagnosis of ESS.

Aims: Endometrial stromal sarcomas (ESSs) are divided into low-grade and high-grade subtypes, with the latter showing more aggressive clinical behaviour. Although histology and immunophenotype can aid in the diagnosis of these tumours, genetic studies can provide additional diagnostic insights, as low-grade ESSs frequently harbour fusions involving JAZF1/SUZ12 and/or JAZF1/PHF1, whereas high-grade ESSs are defined by YWHAE-NUTM2A/B fusions. The aim of this study was to evaluate the utility of a next-generation sequencing (NGS)-based assay in identifying ESS fusions in archival formalin-fixed paraffin-embedded tumour samples., Methods and Results: We applied an NGS-based fusion transcript detection assay (Archer FusionPlex Sarcoma Panel) that targets YWHAE and JAZF1 fusions in a series of low-grade ESSs (n = 11) and high-grade ESSs (n = 5) that were previously confirmed to harbour genetic rearrangements by fluorescence in-situ hybridization (FISH) and/or reverse transcription polymerase chain reaction (RT-PCR) analyses. The fusion assay identified junctional fusion transcript sequences that corresponded to the known FISH/RT-PCR results in all cases. Four low-grade ESSs harboured JAZF1-PHF1 fusions with different junctional sequences, and all were correctly identified because of the open-ended nature of the assay design, using anchored multiplex polymerase chain reaction. Seven non-ESS sarcomas were also included as negative controls, and no strong ESS fusion candidates were identified in these cases., Conclusions: Our findings demonstrate good sensitivity and specificity of an NGS-based gene fusion assay in the detection of ESS fusion transcripts., (© 2016 John Wiley & Sons Ltd.)

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., (Copyright © 2016 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.)

Uterine sarcomas have rarely been diagnosed after uterine artery embolization. It remains unclear whether the diagnostic work-up is required prior to such embolization to prevent a missed diagnosis of sarcomas and a delay in providing definitive treatment. Because of the rarity and heterogeneity of endometrial stromal neoplasms, little is known about their epidemiology, pathogenesis, and molecular pathology. The authors report a case of low-grade endometrial stromal sarcoma (ESS) diagnosed after uterine fibroid embolization. Although they performed laparoscopic biopsy of the rapidly growing uterine mass, they could not detect the ESS. Although rare, ESS should be considered in the differential diagnosis of uterine fibroid enlargement. It is essential to assess the risk of malignancy by taking into account the patient's clinical symptoms, results of the physical exam, and imaging findings prior to uterine artery embolization. Pathologic diagnosis should include an adequate biopsy sample and the use of molecular genetic testing.

MDM2 amplification is known to occur in a variety of neoplasms and its detection by fluorescence in situ hybridization is helpful in distinguishing well-differentiated and dedifferentated liposarcoma from classic lipoma. We recently evaluated a mesenteric mass initially diagnosed as dedifferentiated liposarcoma, largely due to the neoplasm's myxoid morphology and MDM2 expression by immunohistochemistry, from a 46-yr-old woman with a history of uterine low-grade endometrial stromal sarcoma (LG-ESS) with a JAZF1 rearrangement. Our workup of the mesenteric mass revealed a JAZF1 rearrangement and a revised diagnosis of metastatic LG-ESS with myxoid change was rendered. Retrospective testing of the mesenteric mass was negative for MDM2 amplification, an uncommon, but known diagnostic pitfall in MDM2 expression by immunohistochemistry. As MDM2 amplification is not specific for the diagnosis of liposarcoma, we investigated its occurrence in 43 cases of endometrial stromal tumors: 14 uterine LG-ESS, 11 metastatic or recurrent uterine LG-ESS, 8 undifferentiated uterine sarcomas, 5 endometrial stromal nodules, and 4 high-grade ESS with YHWAE rearrangement. In addition, 40 of the 43 cases had previously undergone fluorescence in situ hybridization analysis of JAZF1, PHF1, and YHWAE. Two of the 43 cases (5%) had MDM2 amplification: one was a uterine LG-ESS (JAZF1 rearrangement) and the other was a undifferentiated uterine sarcoma (polysomy intact JAZF1, PHF1, and YHWAE), both metastatic to the lung. Both cases positive for MDM2 amplification showed MDM2 expression by immunohistochemistry. At last follow-up, both patients had died of disease (19 and 60 mo). Our study is the first to demonstrate MDM2 amplification in endometrial stromal tumor. Awareness of MDM2 amplification in endometrial stromal tumor is critical; particularly in locations more common to liposarcoma, to avoid diagnostic errors.

In recent years there have been significant advances in our understanding of female genital tract tumours due to the fact that new molecular abnormalities and translocations have been identified in certain neoplasms. Also, terminology of various lesions in the gynaecological tract has changed and a couple of new entities have been described.In this review we will highlight some mesenchymal neoplasms including gynaecological perivascular epithelioid cell tumour (PEComa), inflammatory myofibroblastic tumour (IMT) occurring in the uterus and discuss and review terminology of endometrial stromal neoplasms.A recently described entity, gastric type endocervical adenocarcinoma will be reviewed, summarising its most salient microscopic and clinical features. The newly proposed endocervical adenocarcinoma classification system by Silva and collegues will be reviewed as well.Finally, a particular high-grade endometrial carcinoma (undifferentiated endometrial carcinoma) will be discussed highlighting the importance of its recognition and differential diagnosis.

Aims: To perform a population-based review of monomorphic endometrial stromal tumours and their histological mimics presenting over a 20-year period, including an evaluation of fluorescence in-situ hybridization (FISH) for the JAZF1 and YWHAE breakaparts., Methods and Results: Forty-nine tumours were examined, comprising 13 histological mimics and 36 endometrial stromal tumours [six stromal nodules (ESNs), 25 low-grade stromal sarcomas (ESSs), and five monomorphic undifferentiated sarcomas (mUESs)]. Nine ESSs showed variant histological patterns, including smooth muscle, sex cord-like/glandular, fibrous or rhabdoid differentiation. Three ESSs were initially misclassified as benign uterine lesions, and, conversely, three benign mimics were originally reported as ESSs. One mUES showed a prominent pseudopapillary pattern. Fluorescence in-situ hybridization demonstrated JAZF1 breakaparts in five of six ESNs and 16 of 25 ESSs; however, only three of nine ESS variants were positive. YWHAE breakaparts were present in four of five mUESs. Analysis of a subsequent metastasis in the YWHAE breakapart-negative mUES demonstrated a YWHAE deletion. None of the histological mimics was positive in FISH analysis. Diffuse cyclin D1 expression was restricted to mUESs in this series., Conclusions: Endometrial stromal neoplasms continue to present diagnostic difficulty. Fluorescence in-situ hybridization analysis is helpful in distinguishing stromal tumours from their histological mimics and in distinguishing ESS from mUES., (© 2014 John Wiley & Sons Ltd.)

Cellular mesenchymal tumors of the uterus may be divided in 2 main groups, smooth muscle and endometrial stromal. Among the former, highly cellular leiomyoma is the classic example. This tumor is not infrequently confused with an endometrial stromal tumor due to its often yellow color and soft consistency, dense cellularity, striking vascularity, not uncommon irregular margin and even rarely association with seedling cellular leiomyomas, both mimicking the infiltration of a low-grade endometrial stromal sarcoma. Cellular intravenous leiomyomatosis can also mimic endometrial stromal sarcoma due to their shared intravascular growth. A variety of histologic features typical of cellular smooth muscle including clefts and differing vasculature help in this distinction. Although endometrial stromal tumors are typically highly cellular, recent studies have expanded their spectrum to include those that are less so due to smooth muscle metaplasia, fibrous and myxoid change, and even oxyphilic cytoplasm. A subset now designated high-grade endometrial stromal sarcoma showing a t(10;17) has been characterized to show small epithelioid cells associated with brisk miotic activity, typically being CD10, ER and PR negative, and cyclin D1 positive. These tumors are juxtaposed to areas of fibromyxoid endometrial stromal neoplasia in 50% of cases. An enigmatic category of uterine mesenchymal neoplasms, often densely cellular, are those descriptively referred to as "uterine tumors resembling ovarian sex cord tumors." Their spectrum is briefly noted as is their crucial distinction from stromal sarcoma with sex cord-like differentiation. Other tumors that rarely occur in the uterus that are densely cellular include but are not limited to undifferentiated uterine sarcoma, embryonal rhabdomyosarcoma, primitive neuroectodermal tumor, lymphoma or small cell, or undifferentiated carcinoma. In this essay, I review the most helpful morphologic, immunohistochemical, and/or cytogenetic features in the diagnosis of each one of these entities.

Endometrial stromal tumors (ESTs) are composed of cells resembling endometrial stroma, and are divided into benign and malignant types based on morphology. Endometrial stromal nodule (ESN) is a benign localized tumor, and endometrial stromal sarcoma (ESS) is an infiltrative and potentially metastatic neoplasm. A series of genetic aberrations contribute to pathological diagnosis of ESTs. At present, subsets of ESN and ESS-low grade (ESS-LG) are characterized as JAZF1-SUZ12/JJAZ1 gene fusion. The ESTs that show higher grade atypia but lack nuclear pleomorphism include YWHAE-FAM22 ESS. Here we report an unusual case of ESTs. Sudden colonic perforation occurred to the patient, and emergency surgery was performed. Pathological findings suggested metastatic ESS. Thorough medical examination of the genital organs detected a 1 cm-sized well-demarcated uterine tumor. Microscopically, the tumor lacked infiltrative features, conforming to the definition of ESN. Both lesions demonstrated identical cytology and shared JAZF1-SUZ12 gene fusion. Endometriosis was not found in any areas of the resected organs, strongly suggesting that the uterine orthotopic tumor metastasized. The current case uncovered the problems of differential diagnosis between ESN and ESS-LG. We demonstrate detailed pathological features of the two lesions, and discuss the possibility of orthotopic EST with limited infiltration to develop into ESS-LG., (© 2014 The Authors. Pathology International © 2014 Japanese Society of Pathology and Wiley Publishing Asia Pty Ltd.)

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.

The World Health Organization (WHO 2003) recognizes 3 endometrial stromal neoplasms: noninvasive endometrial stromal nodule and the 2 invasive neoplasms, endometrial stromal sarcoma (ESS), low grade and undifferentiated endometrial sarcoma (UES). It is important to note that the WHO 2003 does not define moderate atypia (an important differentiating diagnostic criterion for ESS, low grade and UES), nor does it discuss its significance. Moreover, studies on reproducibility and additional prognostic value of other diagnostic features in large are lacking. Using strict definitions, we analyzed the agreement between routine and expert-review necrosis and nuclear atypia in 91 invasive endometrial stromal neoplasias (IESN). The overall 5-year and 10-year recurrence-free survival rate estimates of the 91 IESN patients were 82% and 75%, respectively. Necrosis was well reproducible, and nuclear atypia was reasonably well reproducible. The 10-year recurrence-free survival rates for necrosis absent/inconspicuous versus prominent were 89% and 45% (P<0.001) and those for review-confirmed none/mild, moderate, severe atypia were 90%, 30%, and <20% (P<0.00001). Therefore, cases with moderate/severe atypia should be grouped together. Nuclear atypia and necrosis had independent prognostic values (Cox regression). Once these features were taken into account, no other feature had an independent additional prognostic value, including mitotic count. Using "none/mild atypia, necrosis absent/inconspicuous" as ESS, low grade versus "moderate/severe atypia present or necrosis present" as UES resulted in 68 ESS, low grade and 23 UES cases with disease-specific overall mortality-free survival of 99% versus 48% (P<0.00001, hazard ratio=45.4). When strictly defined microscopic criteria are used, the WHO 2003 diagnoses of ESS, low grade and UES are well reproducible and prognostically strong.

Aims:   The aim of this study was to determine the value of morphometric features in distinguishing mild and moderate atypia and predicting the recurrence of World Health Organization 2003-defined endometrial stromal sarcoma and highly malignant undifferentiated endometrial sarcoma., Methods and Results:   Nuclear and cytological size, shape and arrangement were morphometrically evaluated in 41 cases with consensus no/mild (n = 38) or moderate (n = 3) atypia. None of the cases showed necrosis. The prognostic value of these features in predicting recurrence was also assessed. Seven features differed. The mean and standard deviation of the nuclear volume and the distance between the nuclei were the best discriminators between the no/mild and moderate atypia, with the maximum of the nuclear volume being a practically and rapidly evaluable alternative. With the use of these features, all mild and moderate atypias were correctly classified. Seven cases recurred. The distance between the nuclei and the percentage of nuclei with one neighbour (assessed with morphometric minimum spanning tree analysis) predicted recurrence., Conclusions:   In invasive endometrial stromal tumours, morphometric features are useful diagnostic support tools for distinguishing mild from moderate atypia and predicting recurrence., (© 2013 Blackwell Publishing Ltd.)

Smooth muscle and endometrial stromal tumours represent the two most common uterine mesenchymal neoplasms that may present diagnostic dilemmas for the practising surgical pathologist. Recent changes in morphological and staging criteria, as well as the discovery of new immunohistochemical markers, have improved the diagnosis and classification of these tumours. We highlight the difficulty in distinguishing tumour cell necrosis from infarct-type necrosis and the limited utility of p16 immunohistochemical expression in the diagnosis of leiomyosarcoma. We also discuss the controversial use of mitotic activity and necrosis as prognostic factors in endometrial stromal sarcomas. Emerging genetic information has also greatly expanded our understanding of 'sarcomagenesis' in both tumour types and may provide insight into potential therapeutic targets for the treatment of leiomyosarcoma and endometrial stromal sarcomas, harboring MED12 (mediator complex subunit 12) mutations and recurrent gene rearrangements, respectively. In this review, we discuss the core updates in the diagnosis and classification of uterine leiomyosarcomas and endometrial stromal sarcomas, highlighting new and important molecular genetic findings that may drive pathogenesis., (© 2012 Blackwell Publishing Limited.)

Parasitic myomas are rare and their ethiopathogenesis is uncertain. They may develop from a detached fibroid adhering to an extrauterine surface in order to obtain new blood supply. It has been stated that they form from uterine or myoma fragments left behind after morcellation in the abdominopelvic cavity and thus are called "iatrogenic". Surgeons must be aware of this recently reported complication related to the increasing number of laparoscopic procedures. Thorough inspection and washing of the abdominal cavity are recommended. A case of a patient with iatrogenic parasitic myomas, which appeared six years after a laparoscopic supracervical hysterectomy involving a morcellator, is reported.

Background: Fertility-sparing management of endometrial stromal sarcoma has been demonstrated, but reports of pregnancy after such management are rare in our current body of literature., Case: A 16-year-old nulligravid adolescent girl presented with symptoms of menometrorrhagia and was found to have a 17-cm uterine mass. The patient underwent local resection of the mass with uterine reconstruction. Pathology revealed a low-grade endometrial stromal sarcoma. She was placed on high-dose daily megestrol acetate therapy and remained disease-free for 8 years before achieving pregnancy spontaneously. The patient underwent an uncomplicated pregnancy until 34 weeks of gestation, when she presented in preterm labor and underwent cesarean delivery of a liveborn male neonate, with no evidence of disease recurrence., Conclusion: Fertility-sparing management and close follow-up of low-grade endometrial stromal sarcoma may be a viable option for those desiring future fertility.

Malignant mesodermal tumors of the uterus are an inhomogenous group of uterine malignancies with different pathogenesis, clinical presentation and prognosis. These rare tumors represent approximately 1 % of all uterine malignancies. The aggressive carcinosarcomas or mixed muellerian tumors are defined by mixed malignant epithelial and malignant mesodermal histopathology and are of the same precursor cell origin like endometrial cancer. Thus, carcinosarcomas were reclassified by the FIGO as an aggressive type of endometrial cancer and treated like type II endometrial cancer. Adenosarcomas are also mixed tumors with benign epithelial proliferation and malignant mesodermal cell growth, have a good prognosis and represent less than 5 % of all mesodermal uterine malignancies. Besides carcinosarcomas, the pure mesodermal leiomyosarcomas are the most common mesodermal malignancies. Patients with leiomyosarcamos are usually perimenopausal, and although more than half of the patients present with symptoms, diagnosis occurs incidentally in most cases in final histopathologic workup of an excised putative myoma or uterus. Adequate anamnesis, gynecologic examination and careful imaging by transvaginal ultrasound in the preoperative setting might hint to correct differential diagnosis in many cases. Overall the prognosis of uterine leiomyomas is poor. Malignancies of the endometrial stroma are very rare and divided in two subgroups, the mostly estrogen receptor positive endometrial stromal sarcoma, which occur preferably in premenopausal women and show a favorable prognosis, and the very aggressive undifferentiated endometrial sarcomas. The more rare undifferentiated endometrial sarcomas occur in postmenopausal women and most patients die in the first two years after diagnosis. Risk stratification of preoperative differential diagnosis requires improvements and the correct histopathologic workup of mesodermal uterine malignancies is still a challenge for pathologists.

Sclerosing stromal tumor (SST) is a rare benign ovarian neoplasm classified as a type of sex cord stromal tumor that occurs predominantly in young patients. Several reports have described the US, CT and MR features of SST, but there have been no reports of a bilateral calcified SST in a child. We present a case of a bilateral SST of the ovary with calcification in a 12-year-old premenarchal girl and describe the US, CT, MR and pathological findings.

Alterations in beta-catenin degradation cause it to accumulate to immunohistochemically detectable levels in the nuclei of tumor cells. Although it has been shown that nuclear beta-catenin immunostaining is useful for the diagnosis of some mesenchymal tumors, there is little known about beta-catenin expression in endometrial stromal tumors. In this study, nuclear beta-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 beta-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 beta-catenin. Nuclear beta-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 beta-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 beta-catenin. beta-catenin mutations were rare in endometrial stromal tumors. Taken together, these results indicate that nuclear beta-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.

Tumors of the uterus resembling ovarian sex cord tumors were reported by Clement and Scully in 1976 and were divided in 2 groups: group 1, endometrial stromal tumors, and group 2, mural uterine tumors-both with elements resembling ovarian sex cord tumors. In the former, the sex cord component constitutes a minor portion of an endometrial stromal neoplasm, whereas in the latter, it is the predominant or exclusive component of a uterine wall lesion composed of a variety of mesenchymal elements. An origin from endometrial stromal cells, adenomyosis, stromal myosis, endometriosis, or multipotential cells within the myometrium was postulated in both groups of tumors. In group 1 tumors, the prognosis depends on the type, grade, and stage of the underlying stromal neoplasm. Group 2 tumors seemed to be benign, although because of the occasional recurrence of these tumors, they should be considered of low-grade malignant potential. In recent years, the histological features in group 2 were found to be much more varied than those in group 1 and consisted among others of retiform areas, glomeruloid structures, and Leydig-like cells. In group 1 tumors, the sex cord elements remained limited to cords, trabeculae, nests, and tubules. Eventually, the abbreviation ESTSCLE, or endometrial stromal tumors with sex cord-like elements, was given to group 1 tumors, whereas UTROSCT, or uterine tumor resembling ovarian sex cord tumor, was used for group 2 tumors. The most significant information in recently conducted studies concerns the immunophenotype of these lesions especially of UTROSCT. Out of the plethora of the immunohistochemical stains, a panel of 4 including calretinin, inhibin, CD99, and Melan A has emerged which seemed to be the most characteristic sex cord markers. Positivity for calretinin and at least for 1 of the other above-mentioned markers may thus confirm the diagnosis of UTROSCT. Endometrial stromal tumors with sex cord-like elements, on the other hand, usually express only 1 sex cord marker, mostly calretinin. However, additional studies are necessary to confirm these observations. In conclusion, UTROSCT and, to a lesser degree, ESTSCLE, are polyphenotypic neoplasms, which, according to the evidence available at present, most likely arise from pluripotential uterine mesenchymal cells. In UTROSCT, the differentiation into sex cord components is predominant or exclusive, whereas in ESTSCLE, it is minor.

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.

The depth of myometrial invasion (DMI) is one of the most important prognostic indicators and determinants of therapy in endometrial cancer. There are well-documented problems in recognizing DMI. We examined 100 previously diagnosed endometrioid endometrial carcinomas in hysterectomy specimens, reassessed DMI, and explored morphological features that complicated appraisal of myometrial invasion. The DMI was different from the original measurement in 29% of cases. Twelve percent of all cases (40% of cases with measurement discrepancies) involved differences in the assignment of invasion categories (noninvasive, < or =50% myometrial invasion, and >50% myometrial invasion). Nearly all endometrial cancers originally diagnosed as invasive were considered noninvasive on review. We examined whether the distribution of stromal metaplasia, noninvasive patterns (exophytic tumors, irregular endomyometrial junctions, and adenomyosis), and myometrial invasion patterns were different in cases with and without measurement discrepancies. Irregular endomyometrial junctions, exophytic tumors, and adenomyosis tended to coexist and were more common in the cases with DMI discrepancies. Although there seemed to be a relationship between smooth muscle metaplasia and exophytic tumors, it did not appear that smooth muscle metaplasia was significantly more common in cases with measurement difficulties. However, cases with extensive smooth muscle metaplasia posed problems with assessment of myometrial invasion. Patterns of myometrial invasion other than the conventional destructive pattern were sufficiently uncommon as to not impact on DMI measurement in large numbers of cases. Measuring the DMI is usually uncomplicated, but additional scrutiny should be paid to cases involving exophytic tumors, irregular endomyometrial junctions, adenomyosis, and extensive stromal smooth muscle metaplasia.