A Tumour in Disguise in the Right Palm- Monophasic Synovial Sarcoma

• Main Authors: Vasugi Gramani Arumugam, Sandhya Sundaram, Anita Ramesh, Prathiba Duvuru, Srinivasa Rajappa
• Format: Article
• Language: English
• Published: JCDR Research and Publications Private Limited 2016-05-01
• Series: Journal of Clinical and Diagnostic Research
• Subjects: epithelial type; malignant soft tissue tumour; mucin vacuoles
• Online Access: https://jcdr.net/articles/PDF/7748/11112_CE(Ra1)_F(GH)_PF1(RSAK)_PFA(AK)_PF2(PAG).pdf

Synovial sarcoma is one of the poorly differentiated malignant soft tissue tumour occuring commonly among young adults in the extremities. We report a 50-year-old female presenting with a soft tissue mass in the right palm. On examination, a single firm and non tender swelling was noticed adjacent to the thenar muscles. Radiology suggested a benign soft tissue lesion. The swelling, clinically thought to be a lipoma, was excised and sent for histopathological examination. Microscopy showed a highly cellular tumour arranged in nests, cords and pseudo glandular pattern separated by dense fibrocollagenous tissue. An interesting and baffling finding was the presence of a distinct mucin vacuole in many of the tumour cells. A diagnosis of soft tissue sarcoma with epithelial features was considered and a panel of immunohistochemical stains done. Tumour cells showed strong positivity for cytokeratin 7, vimentin, EMA & Bcl2. CD 99 and S100 were focally positive. CD 34 and CEA were negative. In view of the above microscopic and immunohistochemical findings, a diagnosis of monophasic synovial sarcoma of epithelial type was rendered. This case is being documented for the rare morphological appearance of mucin vacuoles in a monophasic epithelial type synovial sarcoma.