Cutaneous Histoplasmosis in HIV Seronegative Patients: A Clinicopathological Analysis

Abstract

<b><i>Background:</i></b> Diagnosis of extrapulmonary histoplasmosis in HIV seronegative and immunocompetent patients is often challenging, so a high index of suspicion is required. Cutaneous manifestation of infection shows a wide spectrum of lesions including erythematous plaques; maculopapules; crusted, verrucous, or desquamative papules and nodules; abscesses; and mucocutaneous ulcers among others. Due to the variations in its clinical presentation, histopathology plays a very important role in the detection of spores and the confirmation of diagnosis. <b><i>Objectives:</i></b> The aim of our study was to analyze clinicopathological characteristics of cutaneous manifestations of biopsy-proven histoplasmosis in HIV seronegative individuals. We also examined the utility of Fite stain for the diagnosis of <i>Histoplasma capsulatum</i> on tissue biopsy sections. <b><i>Methods:</i></b> This was a retrospective, observational study on 7 patients who were HIV seronegative and clinically manifested with isolated cutaneous lesions or disseminated disease. Skin biopsy from the lesions was performed on all 7 patients. In addition to H&amp;E staining and special stains for detecting fungus, Fite staining was performed on all of the cases to study its utility in detecting <i>H. capsulatum</i> spores. <b><i>Results:</i></b> The skin lesions were widely disseminated in all patients and the most common cutaneous lesions were papules, present in all 7 patients. On review of the H&amp;E-stained slides, the most common pattern was histiocytic lobular panniculitis-like infiltrate observed in 4 cases. Fite stain highlighted the yeast as magenta-colored spores on a blue background in all cases, except for 1 with a granulomatous pattern. <b><i>Conclusion:</i></b> A primary cutaneous manifestation of <i>H. capsulatum</i> infection in non-HIV-infected individuals is extremely rare. Fite stain could aid in differentiating the spores of <i>H. capsulatum</i> from those of other fungi, <i>Cryptococcus</i> and <i>Candida</i> in particular.