Post-Traumatic Epidermoid Cyst of the Palm-Case Report and Review of the Clinical Characteristics and Differential Diagnosis with Tenosynovitis

Abstract

Background:Epidermoid cyst is the most common cutaneous cyst, and it can occur on almost any skin surface. It often presents as a bulging, round, smooth-surfaced, and freely mobile mass with variable size.Less than 10% of epidermoid cysts occur on the extremities, and even fewer occur on the palms and soles.Aim and Objectives:Herein, we report a case with an epidermoid cyst of left palm. Sonographically, ruptured epidermoid cysts may mimic tenosynovitis. Articles about the clinical characteristics of epidermoid cysts and differential diagnosis with tenosynovitis are reviewed.Materials and Methods:A 17-year-old male patient had an accidental penetrating injury to his left palm from a compass 3 years ago, and it healed as a palpable and well-defined skin mass. He received incision and drainage about 4 months ago, but the mass still persisted with yellowish discharge. Ultrasonographic findings were in favor of tenosynovitis. We performed exploratory surgery, and the mass was excised completely.Results:The pathologic report confirmed the diagnosis of a ruptured epidermoid cyst. There was no recurrence after a one-year follow-up.Conclusion: Post-traumatic epidermoid cysts occur mainly on palms, fingers and soles. Sonographically, ruptured epidermoid cysts may mimic any other soft tissue mass or disease. A thorough history taking and physical examination are the most important factors for definite diagnosis. Complete excision is the curative treatment of choice.