Cutaneous malacoplakia: a report of two cases and review of the literature.

Malacoplakia, an inflammatory disease characterized by accumulations of phagocytic macrophages, occurs primarily in immunocompromised individuals. Cutaneous involvement is rare. Two men, each with a renal allograft, had expanding nodules on the temple and perianal area (case 1) and perianal, inguinal, and scrotal skin (case 2). Lesions resolved after combined surgical and antibiotic therapy. Histopathologic examination showed dense infiltration with large phagocytic macrophages containing round, concentric, laminar Von Kossa stain-positive inclusion bodies. Histiocytes had positive results for CD 68, lysozyme, and alpha 1-antitrypsin. Electron microscopic examination demonstrated rare intracytoplasmic inclusion bodies with concentric electron-dense laminations of calcium (Michaelis-Gutmann bodies.) Cutaneous malacoplakia should be considered in the differential diagnosis of nodules or draining ulcers, particularly in immunocompromised patients. Because Michaelis-Gutmann bodies are difficult to identify, specimens should be evaluated for cutaneous malacoplakia by immunohistochemical or electron microscopic means.