Background: Cutaneous metaplastic synovial cyst (CMSC) is a rare cystic tumor that is unfamiliar to most dermatologists. A traumatic history usually precedes its onset. CMSC is often misdiagnosed as suture granuloma clinically. A correct diagnosis requires histopathologic examination to reveal its characteristic features, that is, a cystic tumor line by synovium-like structure.
Objective: To describe a case of CMSC encountered during dermatologic surgery practice. We present an unusual case with elongated projections.
Methods: A case report and literature review are presented.
Conclusion: The differential diagnosis of tender cutaneous cysts should include CMSC. Projections from the cyst wall may attain significant size and give the intraoperative impression of a "bag of worms."