Abstract:

Histoplasmosis usually presents with pulmonary involvement. Hematogenous dissemination can lead to involvement of different organs in immunocompromised patients. Cutaneous involvement is reported in 10-25% of patients with HIV/AIDS and encompasses a wide range of clinical and histological presentations. A 34-year-old HIV- positive man with CD4 count less than 20 presented with fatigue, dizziness, weight loss and disseminated scaly crusted papules around mouth, genitalia, and feet. Biopsy of two lesions revealed pseudoepitheliomatous hyperplasia with intraepidermal and dermal microabscesses. Numerous scattered, 2-4 µm yeast forms were seen within histiocytes, free in the dermis and within the cytoplasm of keratinocytes, morphologically favoring Histoplasma. Subsequent urine antigen test and blood cultures confirmed the diagnosis of disseminated histoplasmosis. Clinical improvement and resolution of cutaneous lesions were achieved by anti-retroviral therapy with liposomal amphotericin followed by itraconazole. Cutaneous histoplasmosis usually shows organisms within parasitized histiocytes in the dermis. This case shows an unusual distribution of Histoplasma within keratinocytes and highlights the importance of recognizing this pattern in cutaneous histoplasmosis. To the best of our knowledge, only one prior case report exists of disseminated histoplasmosis parasitizing keratinocytes; in their case of a patient with leukemia, this intraepidermal pattern was predominant. Our case is the second case to report epidermal colonization by Histoplasma organisms and the first in a patient with HIV/AIDS as cause of immunosuppression. The inability of immune system in an HIV/AIDS patient to eliminate the organism confined to epidermis, emphasizes the importance of appropriate and possible longer course of treatment and follow-up for these group of patients.

Financial Disclosure:
No current or relevant financial relationships exist.

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Negin Farsi, MD