Cutaneous Coccidiomycosis Masquerading as an Epidermoid Cyst: Case Report and Review of the Literature.

OBJECTIVES

To present a challenging case of inoculatory fungal mycosis mimicking an epidermoid cyst, which may have been easily overlooked by the pathologist.

METHODS

We present a case report of a 29-year-old male with a nodule on the right lower back, which was surgically excised and submitted to pathology as a ruptured epidermoid cyst.

RESULTS

Histopathologic sections revealed detached soft tissue fragments containing polymorphic granulomas with abscess and suspicious-appearing spherical structures ranging in size from 50 to 200 μm. Some spherules were located within different types of multinucleated giant cells and most were located in close proximity to abscess. Periodic acid-Schiff fungal stain highlighted these structures and a presumptive diagnosis of coccidiomycosis was rendered. Serologic testing was performed which confirmed exposure to Coccidioides immitis, and extensive work-up for evidence of disseminated disease was negative. Subsequently, additional clinical history was garnered which revealed recent travel history to El Paso, Texas, of many weeks duration for military training, conducted mostly outdoors, subjectively with several encounters of being stuck by vegetation during these exercises.

CONCLUSION

This interesting case highlights important diagnostic histologic clues to consider when evaluating "routine" cyst specimens and highlights the importance of thorough clinicopathologic correlation, even in the "routine."