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Case Reports

Abstract

Cutaneous Malakoplakia – A potential diagnostic pitfall

We present the case of a 34-year-old African American female who presented to an outside clinic with multiple painful, friable 1 to 2 cm nodules on the vulva persisting for one month. Her medical history included peripartum cardiomyopathy, necessitating a heart transplant three years prior, and she was currently on immunosuppressive medications. A previous biopsy of the nodules, conducted elsewhere, suggested infection, leading to a course of acyclovir without improvement. A subsequent biopsy was sent to our institution and showed a polypoid nodule of ulcerated skin containing a mass-forming lesion comprised of CD68+ granular histiocytes and mixed inflammation. The histiocytes exhibited densely eosinophilic granular cytoplasm with multiple foci of gray-blue intracytoplasmic inclusions. Special stains were negative for microorganisms. Von Kossa staining highlighted calcium deposits within the intracytoplasmic inclusions, consistent with calcified Michaelis-Gutmann bodies, and a final diagnosis of malakoplakia was established. Malakoplakia is characterized by a mass-forming granulomatous to histiocytic response to bacterial infection, typically involving Gram-negative organisms. This case underscores the exceptionally rare occurrence of malakoplakia in the skin. It is associated with immunocompromised states and attributed to macrophages' impaired ability to effectively phagocytize bacterial organisms. Accurate differentiation is crucial for the appropriate management of this uncommon lesion.