Cutaneous malakoplakia in a patient with psoriasis

A 58 year old patient suffering from psoriasis vulgaris had typical erythematous, scaly plaques for 20 years. In addition, an erosive, therapy-resistant plaque was found in the perianal region. A biopsy was taken to exclude malignancy; it showed intracytoplasmic Michaelis-Gutmann-bodies as a marker for malakoplakia, which rarely occurs in the skin. In further electron microscopic investigation, intracytoplasmatic bacteria could be demonstrated. An underlying insufficiency with immunosuppression were not found in this patient; both are often associated with malakaplakia.