Disseminated cutaneous histoplasmosis in patients infected with human immunodeficiency virus.

Background: In the pre-AIDS era disseminated histoplasmosis was rare and the cutaneous manifestations thereof were reported infrequently. A range of unusual clinical manifestations of disseminated cutaneous histoplasmosis (DCH) in AIDS patients has been documented, but the cutaneous histopathological descriptions are short and incomplete. In addition, the histopathological spectrum of AIDS-associated DCH is poorly recognized.

Methods: This is a prospective 32-month study of all HIV positive patients diagnosed with histoplasmosis in the Departments of Anatomical Pathology and Dermatology, Nelson R. Mandela School of Medicine and King Edward VIII Hospital, Durban, South Africa. Clinical distribution and morphology of the individual skin lesions and CD4+ lymphocyte counts in the peripheral blood were analysed in relation to the histopathological features of biopsied lesional tissue. Ultrastructural examination of tissue retrieved from the wax blocks of three cases that exhibited dermal karyorrhexis and collagen necrosis was undertaken. Fungal culture of lesional skin tissue was undertaken in all patients.

Results: Twenty-one biopsies of papules (7), nodules (4), plaques (5), erythema multiforme-like lesions (2), vasculitic lesions (2) and exfoliative dermatitis (1) from 14 patients were examined. Of four biopsies (CD4 range: 120-128 cells/mm3) one and three demonstrated necrotizing and non-necrotizing granulomatous inflammation with a paucity of intrahistiocytic microorganisms. Seven biopsies (CD4 range: 2-56 cells/mm3) demonstrated diffuse dermal and intravascular accumulation of histiocytes densely parasitized by Histoplasma capsulatum var. capsulatum. Vasculitis, karyorrhexis or collagen necrosis was not present. Ten biopsies (CD4 range: 2-72 cells/mm3) demonstrated diffuse dermal karyorrhexis, collagen necrosis and interstitial, extracellular H. capsulatum var. capsulatum. Histiocytic disintegration and nuclear fragmentation and release of intact microorganisms and intact and ruptured lysosomes were identified ultrastructurally. Leucocytoclastic vasculitis was present in two biopsies of vasculitic clinical morphology. Microbiological culture confirmed histoplasmosis in all cases. Three patients died before treatment was commenced. Two patients died within the first two days of induction of therapy. Nine patients demonstrated dramatic healing of the cutaneous lesions.

Conclusions: Despite the clinicopathological spectrum of DCH and the attendant host immunocompromise, timely and appropriate treatment of DCH may be lifesaving and allows rapid healing of skin lesions. A high index of clinical suspicion and skin biopsies and culture are crucial for accurate diagnosis.