Cutaneous Microsporidiosis in an Immunosuppressed Patient.

Microsporidia are a group of obligate intracellular parasites that naturally infect domestic and wild animals. Human microsporidiosis is an increasingly recognized multisystem opportunistic infection. The clinical manifestations are diverse with diarrhea being the most common presenting symptom. We present a 52-year-old woman with a history of amyopathic dermatomyositis complicated by interstitial lung disease managed with mycophenolate mofetil and hydroxychloroquine who presented with a seven-month history of recurrent subcutaneous nodules as well as intermittent diarrhea and chronic sinusitis. A punch biopsy demonstrated superficial and deep lymphocytic and granulomatous dermatitis with focal necrosis. Tissue stains for microorganisms revealed oval 1-3 μm spores within the necrotic areas in multiple tissue stains. Additional studies at the Centers for Disease Control confirmed cutaneous microsporidiosis. This case is one of very few confirmed examples of cutaneous microsporidiosis reported in the literature. This article is protected by copyright. All rights reserved.