Under treated necrotizing fasciitis masquerading as ulcerated edematous Mycobacterium ulcerans infection (Buruli ulcer).

We report a case of under treated necrotizing fasciitis (NF) in a 65-year-old woman with diabetes misdiagnosed as Mycobacterium ulcerans infection. She came to the Institut Médical Evangélique (IME) with an extensive painful edematous ulcerated lesion on the dorsum of the right foot and ankle. The diagnosis of Buruli ulcer (BU) was based initially on clinical findings and place of residence (Songololo Territory, the largest known focus of BU in Bas-Congo province). Tissue specimens gave negative results for acid-fast bacilli (AFB), culture, and polymerase chain reaction (PCR) for M. ulcerans. Histopathologic analysis revealed marked necrosis of the lower dermis and subcutaneous tissue. No AFB was found. Later, scattered foci of intracellular gram-positive cocci typical of streptococci were seen. Clinicopathologic correlation of these findings strongly supported the diagnosis of NF. This patient shows the difficulties that may be encountered even in known endemic areas in recognizing BU cases purely on clinical findings.