Premium
Primary intramucosal synovial sarcoma of the sigmoid colon in a patient with a germline mutation in the MSH2 gene: A case report
Author(s) -
Shigematsu Yasuyuki,
Yamashita Kyoko,
Takamatsu Manabu,
Tanizawa Taisuke,
Togashi Yuki,
Nakajima Takeshi,
Chino Akiko,
Kawachi Hiroshi,
Takeuchi Kengo
Publication year - 2020
Publication title -
pathology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.73
H-Index - 74
eISSN - 1440-1827
pISSN - 1320-5463
DOI - 10.1111/pin.13020
Subject(s) - synovial sarcoma , pathology , sarcoma , medicine , microsatellite instability , colonoscopy , epithelioid sarcoma , soft tissue sarcoma , sigmoid colon , colorectal cancer , biology , cancer , gene , rectum , allele , biochemistry , microsatellite
Synovial sarcoma is a high‐grade soft tissue sarcoma that occurs primarily in the deep soft tissue of extremities, and primary colorectal synovial sarcoma is extremely rare. In this report, we present a synovial sarcoma mostly located within the mucosa of the sigmoid colon. The patient was a man in his forties with a germline deletion in the MSH2 gene. He had experienced undifferentiated pleomorphic sarcoma of the left forearm 7 years before and adenocarcinoma of the transverse colon 6 years before, both of which were successfully treated and exhibited no recurrence to date. A surveillance colonoscopy for Lynch syndrome revealed the tumor which had a submucosal tumor‐like appearance with central erosion and endoscopic resection was performed. Histologically, it was composed of monotonous proliferation of spindle cells arranged in cellular fascicles; these findings were compatible with monophasic fibrous synovial sarcoma. In the tumor cells, the presence of the SS18 ‐ SSX1 fusion gene was confirmed. Protein expression of mismatch repair genes was intact in the tumor cells, indicating the association between microsatellite instability and synovial sarcoma was weak. The present case highlights a rare primary site of synovial sarcoma in a patient with Lynch syndrome.