Cutaneous Metaplastic Synovial Cyst of the Cheek Generated by Repetitive Minor Trauma

Abstract

Cutaneous metaplastic synovial cyst (CMSC) refers to a cyst lined by metaplastic synovial tissue including villous structures. It is thought to be a tissue reaction to local trauma, and most cases have a history of preceding surgery or trauma. Clinically, most of the lesion is a tender intradermal nodule that is associated with scar tissue. However, dermatologists have difficulty in diagnosing CMSC because CMSC is reported only rarely and its clinical manifestation can be confused with implantational epidermal cyst, suture granuloma or other cutaneous cysts. Thus, a histopathological exam is mandatory for diagnosis of CMSC. Herein we report the case of an 18-year-old man who developed CMSC on the left cheek on the posterior ramus of the mandible. He had a history of repetitive digital manipulation of the lesion before the onset of CMSC.

Foreign body reaction mimicking perineal nodular induration

“…However, metaplastic synovial cyst is probably best considered as a distinct entity and characteristically displays a cyst-like membrane resembling synovial tissue. 6 Our case not only reminded us of the many faces of foreign body reactions but also introduced us to the entity of perineal nodular induration. Clinical information can often be sparse and activities may be inadvertently excluded.…”

Cutaneous Metaplastic Synovial Cyst

“…3 Within the embryo, the normal synovium develops from a mechanical disruption of the connective tissue; CMSCs form due to the disruption of connective tissue following trauma or surgery. 5 The cyst develops between a few weeks to several years following the trauma. It has no predilection for site, gender or age.…”

“…It has no predilection for site, gender or age. 5 Clinically, CMSCs are tender, erythematous, cutaneous or dermal nodules with or without drainage. 3 CMSC remains a lesser known entity in clinical dermatology.…”

“…3 CMSC remains a lesser known entity in clinical dermatology. 5 It is commonly misdiagnosed and the lack of clinical awareness is an impediment to establishing its true incidence. The swelling is commonly misdiagnosed as a suture granuloma or an epidermal inclusion cyst following surgery or trauma.…”

“…The swelling is commonly misdiagnosed as a suture granuloma or an epidermal inclusion cyst following surgery or trauma. 5 Other differential diagnoses include foreign body granulomas, leiomyomas, eccrine poromas and other cutaneous cysts. 3 Epidermal cysts are distinguished from CMSCs as they are true cysts with an epithelial lining.…”