Abstract
An 11-year-old boy developed a painless erythematous nodule on the right forearm, which gradually became ulcerated and slightly painful. Although the ulcerated nodule was removed at a nearby hospital, the patient developed another ulcer and visited our department in April of 2010. A skin biopsy specimen from the ulcer bed showed numerous acid-fast bacilli in the subcutaneous tissue. The biopsied specimen was subjected to DNA analysis, and the result was compatible with M. ulcerans subsp. shinshuense; the patient was diagnosed with Buruli ulcer. After 6 weeks of incubation in 2% Ogawa egg medium slants and Mycobacterium Growth Indicator Tube, the culture yielded yellow colonies. Two months after starting rifampicin and clarithromycin, the cutaneous ulcer was surgically removed and covered by skin grafting. The patient continued the antibiotics for 6 months, and there was no recurrence in the following 1 month. Buruli ulcer is caused by Mycobacterium ulcerans, one of the nontuberculous mycobacteria that are present in tropical countries. However, very recently, cases of Mycobacterium ulcerans subsp. shinshuense infection have frequently been reported from Japan. Thus, this disease should be considered in the differential diagnosis of a chronic skin ulcer.
