Recurrent cutaneous metaplastic synovial cyst.

Area of Science:

• Dermatology
• Pathology
• Surgical Oncology

Background:

• Cutaneous metaplastic synovial cysts (CMSCs) are recently described lesions.
• Histologically, CMSCs feature a cystic cavity lined by metaplastic synovium-like cells and villous connective tissue cores.
• Clinically, CMSCs present as tender subcutaneous nodules, often misdiagnosed as suture granulomas.

Observation:

• This report details the first case of a recurrent CMSC.
• The patient was a 34-year-old male who developed a CMSC at the site of a previously excised epidermoid cyst.
• The CMSC recurred in the same location after the initial excision.

Findings:

• The histological characteristics of CMSC include a cystic structure with specific cellular lining and connective tissue cores.
• Recurrence of CMSC at the same site after surgical intervention is demonstrated.
• A history of trauma often precedes the onset of CMSC.

Implications:

• CMSCs represent a distinct entity within the spectrum of subcutaneous lesions.
• Recognition of CMSC is crucial for accurate diagnosis and appropriate management.
• CMSCs should be included in the differential diagnosis for tender subcutaneous swellings, particularly in post-surgical or post-traumatic contexts.