Utility of YWHAE fluorescent in-situ hybridisation in mesenchymal tumors of uterus- An initial experience from tertiary oncology centre in India

Background: Endometrial stromal sarcoma (ESS) is a common uterine mesenchymal malignancy. According to World Health Organisation (WHO) 2014 classification, ESSs are further subdivided into low-grade ESS (LGESS) and high-grade ESS (HGESS). HGESS is defined by the presence of YWHAE gene rearrangement and has a poorer prognosis compared to LGESS. METHODS: Twenty-four cases comprising of 16 endometrial stromal sarcoma and 8 lesions mimicking ESS were retrieved from the archives of the Department of Pathology and subjected to fluorescent in situ hybridization (FISH) analysis for YWHAE gene rearrangement. Immunohistochemistry for CD10, ER, PR, Cyclin D1, SMA, H-Caldesmon, Desmin, Ki-67, and Pan Cytokeratin was performed. RESULTS: Two cases with histological features similar to HGESS were positive for YWHAE gene rearrangement while 1 was indeterminate. No cases of LGESS and histological mimics of ESS were positive for this rearrangement. CONCLUSIONS: HGESSs are defined by the presence of YWHAE rearrangement. These tumors present at higher stage and have poorer prognosis. They may not respond to hormonal therapy and may be treated with chemotherapy. Cyclin D1 though not specific remains a sensitive tool to triage endometrial stromal sarcomas for this FISH study.

Pseudopapillary prostatic adenocarcinoma: A diagnostic pitfall for pathologists.

Prostatic adenocarcinoma and urothelial carcinoma are common tumours seen in elderly patients. They both act as a close differential diagnosis for each other clinically as well as histologically. Various morphological patterns have been described in prostatic adenocarcinomas. However, pseudopapillary pattern was not described until recently a paper which described seven such cases. These tumours mimic urothelial carcinoma as the papillary pattern is usually seen in urothelial carcinoma and may act as a pitfall for the diagnosing pathologists. As both the tumours are treated with different therapeutic protocol it is necessary to differentiate the two and hence the pathologist should be aware of this morphological variant of prostatic carcinoma. Critical histological review and immunohistochemical examination is helpful to make the diagnosis. Here we discuss one such case of pseudopapillary prostatic adenocarcinoma mimicking urothelial carcinoma with a brief review of histological and immunohistochemical examination useful to distinguish the two tumours.

Concomitant follicular lymphoma and histiocytic sarcoma: A rare progression, trans-differentiation or co-occurrence.

Trans‑differentiation of follicular lymphoma (FL) into a histiocytic sarcoma (HS) is a rare event and usually occurs as a sequential event. We report a case where in the same node with two distinct areas one of low‑grade FL and another with HS was observed. This patient was a 58 years old with generalized lymphadenopathy and Ann Arbor Stage III disease. The cervical node biopsy on histological examination revealed two distinct areas, firstly a FL with nodular architecture and the other a smaller focus of sheets of pleomorphic histiocytic cells diffusely arranged at the edge of the section contiguous with FL with few cells in transiting phase. On immunohistochemistry the FL was positive for CD20, CD10, PU.1, PAX5 and Bcl2, while the large histiocytic cells were positive for CD163, CD68, LCA, and PU.1, weakly for PAX5 and negative for CD20, CD10, CD30, CD3, CD1a, Bcl2, S100, and Alk‑1. The therapeutic implications of this diagnosis and postulated theories on trans‑differentiation are discussed.