Mycobacterium ulcerans infection (Buruli ulcer): a case report of the disseminated nonulcerative form.

The World Health Organization recognizes Mycobacterium ulcerans infection (Buruli ulcer) as a reemerging disease. Classically, lesions are indolent, undermined ulcers of the skin. The characteristic histopathologic changes are provoked by a soluble toxin of M ulcerans that is necrotizing and immunosuppressive. After tuberculosis and leprosy, Buruli ulcer is the third most common mycobacterial disease in humans. We report Buruli ulcer in a patient in Benin, West Africa, with widespread edema and diffuse induration of approximately one half of the skin of the trunk. There was no ulceration. The tissue studied was a 16-cm portion excised from the center of the large surgical specimen. Histopathologic analysis showed massive contiguous necrosis of the dermis and subcutis in sections of biopsy specimens from the center, at 2-cm intervals in two radii from the center to the periphery, and at 5-cm intervals around the margin. Acid-fast bacilli infiltrated all specimens except at one peripheral site. Samples of the entire surgical specimen taken from seven sites before fixation were polymerase chain reaction and culture positive for M ulcerans. The disseminated nonulcerative form of M ulcerans infection is well known, but is now increasingly frequent in some highly endemic areas, especially in West Africa. This patient died within 48 hours postsurgery, but cause of death was not established. The only regularly effective treatment for advanced lesions is surgical excision of all infected tissue. Estimation of the lateral limits of invasion by M ulcerans may help the surgeon establish the optimal extent of excision. Refinement of the basic concept we used and adaptation to preoperative assessment of the limit of bacterial invasion are urgently needed, especially for massive lesions.