Disseminated Mycobacterium haemophilum causing granulomatous mastitis

We present the case of a 58-year-old female with celiac disease, obesity, and recently diagnosed type 2 diabetes mellitus who developed a rash on her left thigh which spread and progressed to her arms, face, and abdomen. A biopsy of the left forearm grew Mycobacterium haemophilum. Weeks after the diagnosis of the M. haemophilum skin infection, the patient underwent a screening mammogram which showed new masses in both breasts. A biopsy of a left breast mass revealed cystic granulomatous inflammation with scattered neutrophils and lymphocytes within fibroadipose tissue. PCR and sequencing from breast tissue and AFB culture confirmed M. haemophilum. The patient was also later diagnosed with sinonasal involvement. No underlying immunodeficiency has been identified. This case highlights dissemination of M. haemophilum to multiple sites including skin, breast, and sinonasal tissues in a diabetic patient who was not otherwise immunocompromised. To our knowledge, it is the first reported case of granulomatous mastitis caused by M. haemophilum.