Mycobacterium haemophilum: A report of cutaneous Infection in a Patient with end-stage renal disease

Mycobacterium haemophilum is a slow-growing nontuberculous mycobacterium (NTM) that can cause ulcerating cutaneous or subcutaneous nodular skin lesions in immunocompromised and immunocompetent patients. Acid-fast staining cannot distinguish NTM from M. tuberculosis; culturing at two temperatures with iron-supplemented media and polymerase chain reaction (PCR) are needed for optimal detection of M. haemophilum.Case presentationA 32-year-old man with end-stage renal disease, undergoing hemodialysis twice a week, presented with multiple, painless, nonpruritic nodular lesions. A formalin-fixed paraffin-embedded tissue block from his finger lesion was sent to the Department of Pathology, Masih Daneshvari Hospital for consultation. The lesions were primarily diagnosed to be dermatofibroma by another pathologist.On microscopic examination, vague granuloma with areas of necrosis was observed. The diagnosis was established by positive acid-fast staining, negative PCR results for M. tuberculosis complex, and positive nested PCR results for M. haemophilum.ConclusionCutaneous lesions in immunocompromised patients with positive results in acid-fast staining and negative results for M. tuberculosis should be further assessed using skin culture and molecular techniques to identify rare, atypical mycobacterial species like M. haemophilum