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Query: UMLS:C0268596 (EMA)
 2,520 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cutaneous myoepithelial tumors demonstrate heterogenous morphologic and immunophenotypic features. We previously described, in brief, 7 cases of cutaneous myoepithelioma showing solid syncytial growth of ovoid, spindled, or histiocytoid cells. We now present the clinicopathologic features in a series of 38 cases of this distinctive syncytial variant, which were diagnosed between 1997 and 2012 (mostly seen in consultation). There were 27 men and 11 women, with a median age of 39 years (range, 2 mo to 74 y). Primary anatomic sites were the upper extremity (11, including 2 on the hand), upper limb girdle (3), lower extremity (14; 3 on the foot), back (6), face (2), chest (1), and buttock (1); the typical presentation was as either a polypoid or papular lesion. Tumors were well circumscribed and centered in the dermis and ranged in size from 0.3 to 2.7 cm (median 0.8 cm). Microscopically all tumors showed a solid sheet-like growth of uniformly sized ovoid to spindled or histiocytoid cells with palely eosinophilic syncytial cytoplasm. Nuclei were vesicular with fine chromatin and small or inconspicuous nucleoli and exhibited minimal to no atypia. Mitoses ranged from 0 to 4 per 10 HPF; 28 tumors showed no mitoses. Necrosis and lymphovascular invasion were consistently absent. Adipocytic metaplasia, appearing as superficial fat entrapped within the tumor, was seen in 12 cases. Chondro-osseous differentiation was seen in 1 tumor. All tumors examined were diffusely positive for EMA, and the majority showed diffuse staining for S-100 protein (5 showing focal staining). Keratin staining was focal in 1 of 33 tumors and seen in rare cells in 3 other cases. There was also positivity for GFAP (14/33), SMA (9/13), and p63 (6/11). Most lesions were treated by local excision. The majority of tumors tested (14/17; 82%) were positive by fluorescence in situ hybridization for EWSR1 gene rearrangement; testing for potential fusion partners (PBX1, ZNF444, POU5F1, DUX4, ATF1, CREB1, NR4A3, DDIT3, and NFATc2) was negative in all EWSR1-rearranged tumors. No FUS gene rearrangement was detected in 2 tumors lacking EWSR1 rearrangement. Follow-up information is available for 21 patients (mean follow-up 15 mo). One patient with a positive deep margin developed a local recurrence 51 months after initial biopsy. All other patients with available follow-up information, including 11 who had positive deep margins, are alive with no evidence of disease and no reported metastases. In summary, cutaneous syncytial myoepithelioma is a morphologically distinct variant that more frequently affects men, occurs over a wide age range, and usually presents on the extremities. Tumors are positive for S-100 protein and EMA, and, unlike most myoepithelial neoplasms, keratin staining is infrequent. EWSR1 gene rearrangement is present in nearly all tumors tested and likely involves a novel fusion partner. Prior reports describe some risk of recurrence and metastasis for cutaneous myoepithelial tumors; however, the syncytial variant appears to behave in a benign manner and only rarely recurs locally.
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PMID:Cutaneous syncytial myoepithelioma: clinicopathologic characterization in a series of 38 cases. 2358 65

The genetics of myoepithelial tumors (ME) of soft tissue and bone have recently been investigated, with EWSR1-related gene fusions being seen in approximately half of the tumors. The fusion partners of EWSR1 so far described include POU5F1, PBX1, ZNF444 and, in a rare case, ATF1. We investigated by RNA sequencing an index case of EWSR1-rearranged ME of the tibia, lacking a known fusion partner, and identified a novel EWSR1-PBX3 fusion. The fusion was further validated by reverse transcriptase polymerase chain reaction and fluorescence in situ hybridization (FISH). To evaluate if this is a recurrent event, an additional cohort of 22 EWSR1-rearranged ME cases lacking a fusion partner were screened by FISH for abnormalities in PBX3 gene. Thus, two additional cases were identified showing an EWSR1-PBX3 gene fusion. One of them was also intraosseous involving the ankle, while the other occurred in the soft tissue of the index finger. The morphology of the EWSR1-PBX3 fusion positive cases showed similar findings, with nests or sheets of epithelioid to spindle cells in a partially myxoid to collagenous matrix. All three cases showed expression of S100 and EMA by immunohistochemistry. In summary, we report a novel EWSR1-PBX3 gene fusion in a small subset of ME, thereby expanding the spectrum of EWSR1-related gene fusions seen in these tumors. This gene fusion seems to occur preferentially in skeletal ME, with two of the three study cases occurring in intraosseous locations.
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PMID:EWSR1-PBX3: a novel gene fusion in myoepithelial tumors. 2523 Dec 31

A new case of soft tissue myoepithelial carcinoma (MEC) with rhabdoid-like differentiation is presented including cytologic, histopathologic, immunohistochemical, and molecular biologic features. A 45-year-old woman was admitted to the Hospital with nodular mass involving the lower part of the abdominal wall. Fine-needle aspiration cytology showed a round cell tumor with abundant cytoplasm in the myxoid background. The nuclei were uniform, round to ovoid, with finely distributed chromatin, nucleoli, and pale, vacuolated, or eosinophilic cytoplasm with rhabdoid-like appearance resembling a soft tissue malignant rhabdoid tumor. The surgically removed tumor was poorly demarcated, yellow, soft, and myxoid. The histopathology revealed sheets of poorly differentiated round malignant cells with focal myxoid stroma and rhabdoid-like morphology. Immunohistochemistry showed positivity for CK (AE1/AE3), EMA, S100, vimentin, CD99, and SMA; however desmin, CD34, and gliofibrilar acid protein (GFAP) were negative. Tumor cells revealed loss of INI1 expression. The EWSR1 gene rearrangement was detected by fluorescence in situ hybridization (FISH), but molecular biology failed to detect EWSR1/ETS, EWSR1/NR4A3, EWSR1/DDIT3, EWSR1/ATF1, EWSR1-POU5F1, EWSR1/ZNF444, EWSR1-PBX1 gene fusions. The final diagnosis was soft tissue malignant myoepithelioma with rhabdoid changes and EWSR1 gene rearrangement. The differential diagnosis included soft tissue malignant rhabdoid tumor, cellular extraskeletal myxoid chondrosarcoma, proximal epithelioid sarcoma, and other soft tissue tumor with EWSR1 rearrangement. To our knowledge, this is the first case of MEC with rhabdoid features and description of fine-needle aspiration cytology.
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PMID:Soft tissue myoepithelial carcinoma with rhabdoid-like features and EWSR1 rearrangement: Fine needle aspiration cytology with histologic correlation. 2569 74

Myoepithelial tumors (MET) represent a clinicopathologically heterogeneous group of tumors, ranging from benign to highly aggressive lesions. Although MET arising in soft tissue, bone, or viscera share morphologic and immunophenotypic overlap with their salivary gland and cutaneous counterparts, there is still controversy regarding their genetic relationship. Half of MET of soft tissue and bone harbor EWSR1 or FUS related fusions, while MET arising in the salivary gland and skin often show PLAG1 and HMGA2 gene rearrangements. Regardless of the site of origin, the gold standard in diagnosing a MET relies on demonstrating its "myoepithelial immunophenotype" of positivity for EMA/CK and S100 protein or GFAP. However, the morphologic spectrum of MET in soft tissue and bone is quite broad and the above immunoprofile is nonspecific, being shared by other pathogenetically unrelated neoplasms. Moreover, rare MET lack a diagnostic immunoprofile but shows instead the characteristic gene fusions. In this study, we analyzed a large cohort of 66 MET with EWSR1 and FUS gene rearrangements spanning various clinical presentations, to better define their morphologic spectrum and establish relevant pathologic-molecular correlations. Genetic analysis was carried out by FISH for EWSR1/FUS rearrangements and potential partners, and/or by targeted RNA sequencing. Then, 82% showed EWSR1 rearrangement, while 18% had FUS abnormalities. EWSR1-POU5F1 occurred with predilection in malignant MET in children and young adults and these tumors had nested epithelioid morphology and clear cytoplasm. In contrast, EWSR1/FUS-PBX1/3 fusions were associated with benign and sclerotic spindle cell morphology. Tumors with EWSR1-KLF17 showed chordoma-like morphology. Our results demonstrate striking morphologic-molecular correlations in MET of bone, soft tissue and viscera, which might have implications in their clinical behavior.
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PMID:A morphologic and molecular reappraisal of myoepithelial tumors of soft tissue, bone, and viscera with EWSR1 and FUS gene rearrangements. 3199 43

Despite significant recent advances in characterizing the molecular pathogenesis of undifferentiated round cell neoplasms, rare cases remain unclassified. Here, we report two distinctive undifferentiated round cell tumors occurring in young adults. One tumor presented intrabdominally and the other arose within the abdominal wall. One patient died of disease following local and distance recurrence, despite aggressive chemotherapy and radiotherapy. Morphologically, both tumors were similarly composed of primitive round to epithelioid cells arranged in nests, sheets, and trabecular patterns. The cytoplasm was scant and amphophilic, while the nuclei were round and uniform with brisk mitotic activity. Focal necrosis was present. Immunohistochemically, both tumors were variably positive for S100 and EMA, and one case focally expressed cytokeratin and TLE1. Targeted RNA sequencing revealed in both an identical SS18-POU5F1 fusion gene. Fluorescence in situ hybridization was performed which confirmed SS18 and POU5F1 gene rearrangements. Expression data, relative to over 200 other mesenchymal neoplasms that had undergone targeted RNA sequencing on the same platform, suggested the SS18-POU5F1 tumors cluster with EWSR1/FUS-POU5F1-positive myoepithelial tumors. In view of our limited sample size, additional studies are needed to characterize the breadth of clinical and pathologic findings in these neoplasms. In addition, further investigation is necessary to determine whether this entity represents a clinically aggressive and phenotypically undifferentiated variant of myoepithelial tumors, or perhaps an altogether novel category of undifferentiated round cell sarcoma.
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PMID:Undifferentiated round cell sarcomas with novel SS18-POU5F1 fusions. 3255 80