Botryomycosis is a subacute or chronic bacterial infection, which is characterized by a granulomatous response and granules in which the microorganisms are embedded by a hyaline matrix. It may be caused by several pyogenic bacteria. The mechanism of granule formation is not understood. Treatment is with surgical drainage or resection, whenever possible, and prolonged use of the appropriate antibiotics.

A patient with malignant pyoderma brought into complete remission with immunosuppressive cyclophosphamide treatment after the failure of multiple other therapies is reported. The entity of malignant pyoderma with its clinical characteristics, laboratory and biopsy findings, complications, and modalities of therapy is reviewed.