Abstract

Cystic neutrophilic granulomatous mastitis (CNGM) has a distinctive morphology characterized by small cystic spaces with a concentric rim of primarily neutrophils and epithelioid histiocytes. These cystic spaces have a granular basophilic quality; a gram stain discloses gram-positive bacilli compatible with a Corynebacterium species typically representing Corynebacterium kroppenstedtii. We present the three cases of Corynebacterium related cystic neutrophilic granulomatous dermatitis (CNGD). The male to female ratio was 2:1. The patients ranged in age from 45 to 56. Two patients with a history of immunosuppression presented with upper extremity lesions while one patient without a past medical history had facial lesions. The histology in all three cases was reproducible being in the context of small microcystic foci surrounded by neutrophils and mononuclear cells. Gram positive coccobacillary forms were found within the center of the microcysts. Facial cases are likely reflective of the high concentration of demodex on the face. The natural bacterial endosymbiont for demodex is Corynebacterium kroppenstedtii habitat while its occurrence in parts of the body without a high concentration of demodex could be a sign of impaired immunity. Other potential infectious causes of ringed granulomatous inflammation in the skin are Q-fever due to Coxiella burnetti and certain lipid rich fungal organisms, best exemplified by chromoblastomycosis.