Mouse Anti Human tyrosine 3-monooxygenase or tryptophan 5-monooxygenase activation protein, epsilon Polypeptide Hybridoma [DQUD-ZXIBF-3]

Objectives: Although the World Health Organization (WHO) in 2003 defined endometrial stromal sarcomas (ESSs) in general have a good prognosis, considerable differences in clinical behavior and prognosis may exist between different patients with ESS. The ESSs of the type associated with YWHAE-NUTM2 (previously named YWHAE-FAM22) fusion have a more aggressive clinical behavior and poorer prognosis than conventional ESS. Recently, the WHO 2014 classification recognizes this subset of ESS as a separate entity and classifies these as high-grade ESSs. Recognition of this subset has therefore an important clinical impact. We performed a review of the literature to delineate the clinicopathologic features of ESS patients with anYWHAE-NUTM2 rearrangement, with the goal to recognize this subset of ESS. Methods: We report a case of a woman with WHO 2014-defined high-grade ESS. Furthermore, published English literature was reviewed for YWHAE-FAM22 ESS and uterus. Results: Twenty patients were identified, with a median age of 50 (range, 28-67) years. There were no clinical features able to recognize YWHAE-NUTM2 ESS. However, they characteristically contain specific histopathological features. Furthermore, YWHAE-NUTM2 ESSs are strongly cyclin D1 positive in contrast to conventional low-grade ESSs. Conclusions: YWHAE-NUTM2 ESSs represent a subset of ESSs with an aggressive clinical behavior and poor prognosis. Specific histopathological features may indicate the presence of YWHAE-NUTM2 rearrangement, which subsequently can be confirmed by cyclin D1 immunostaining.

Endometrial stromal sarcomas (ESS) are often underpinned by recurrent chromosomal translocations resulting in the fusion of genes involved in epigenetic regulation. To date, only YWHAE-NUTM2 rearrangements are associated with distinctive high-grade morphology and aggressive clinical behavior. We identified 3 ESS morphologically mimicking myxoid leiomyosarcoma of the uterus and sought to describe their unique histopathologic features and identify genetic alterations using next-generation sequencing. All cases displayed predominantly spindled cells associated with abundant myxoid stroma and brisk mitotic activity. Tumors involved the endometrium and demonstrated tongue-like myometrial infiltration. All 3 were associated with an aggressive clinical course, including multisite bony metastases in 1 patient, progressive peritoneal disease after chemotherapy in another, and metastases to the lung and skin in the last patient. All 3 ESS were found to harbor ZC3H7B-BCOR gene fusions by targeted sequencing and fluorescence in situ hybridization. On the basis of the review of these cases, we find that ESS with ZC3H7B-BCOR fusion constitutes a novel type of high-grade ESS and shares significant morphologic overlap with myxoid leiomyosarcoma.