Poorly differentiated synovial sarcoma showing Homer-Wright rosette structures: a potential diagnostic pitfall

EZH2-mediated H3K27me3 is a predictive biomarker and therapeutic target in uveal melanoma

Although gene mutations and aberrant chromosomes are associated with the pathogenesis and prognosis of uveal melanoma (UM), potential therapeutic targets still need to be explored. We aim to determine the predictive value and potential therapeutic target of EZH2 in uveal melanoma. Eighty-five uveal melanoma samples were recruited in our study, including 19 metastatic and 66 nonmetastatic samples. qRT-PCR, immunohistochemistry staining, and western blotting were applied to detect the expression of EZH2 and H3K27me3. We found that EZH2 (41/85, 48.24%) and H3K27me3 (49/85, 57.65%) were overexpressed in uveal melanoma. The expression of EZH2 was not significantly associated with metastasis. High H3K27me3 expression was correlated with poor patient prognosis. UNC 1999, an EZH2 inhibitor, can downregulate H3K27me3 expression and has the most potency to inhibit OMM1 cell growth by the cell cycle and ferroptosis pathway. These results indicate that H3K27me3 can be a biomarker predicting a poor prognosis of UM. EZH2 is the potential therapeutic target for UM.

Unusual presentation of poorly differentiated primary pulmonary synovial sarcoma (PD-PPSS) diagnosed by EBUS-TBNA with cytogenetic confirmation-A diagnostic challenge

Poorly differentiated primary pulmonary synovial sarcoma (PD-PPSS) is a rare, aggressive neoplasm, which occurs in 0.5% cases of all lung malignancies. The diagnosis of PD-PPSS can be very challenging on cytology samples. We present here an unusual case of PD-PPSS diagnosed by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), in the setting of known history of diffuse large B-cell lymphoma. Diff-Quik and Papanicolaou stains showed cellular specimen with clusters of highly atypical small round blue cells admixed with lymphoid elements; and some with denuded cytoplasm. Cell block further showed molding, crush artifact and atypical mitotic figures. A differential diagnosis based on extended immunohistochemical work-up was Ewing?s sarcoma/PNET versus poorly differentiated synovial sarcoma. Fluorescent in-situ hybridization (FISH) showed SYT gene rearrangement at 18q11.2. In this report, we describe the cytomorphological features, diagnostic pitfalls, challenges, potential mimics, and importance of acquisition of adequate material for the ancillary work-up on the cell block.

Primitive Myxoid Mesenchymal Tumor of Infancy With Rosettes

Primitive myxoid mesenchymal tumor of infancy (PMMTI) is a relatively recently described tumor arising in infants and demonstrating a unique histomorphology. We present an unusual case of PMMTI with rosettes, a hitherto undescribed finding in the reported cases. We also present the cytogenetic and ultrastructural findings of this tumor and review the literature. As awareness of PMMTI increases, additional clinical data and histopathologic findings will aid in the morphologic and behavioral characterization of this neoplasm.