Recurrent epidermal cyst infection caused by Brucella melitensis in a diabetic patient.

A presternal swelling diagnosed clinically as a sebaceous cyst in a 60-year-old diabetic patient was surgically drained, and the aspirated purulant material yielded growth of Brucella melitensis. The swelling recurred four times and was drained on every occasion. The patient responded to surgical excision and antibrucella treatment. The histologic diagnosis was an epidermal cyst.