Vaginal ulceration and local lymphadenopathy in an African immigrant.

(See pages 441–2 for the Photo Quiz) Figure 2. Periodic acid Schiff stain showing ovoid yeasts (diameter, ∼10 mm) with thick cell wall, vacuolated cytoplasm, and narrow-based bud (arrow) (original magnification, ϫ420). Figure 1. Immunohistochemical stain for lysozyme (arrow) revealing a giant cell with multiple ovoid cysts in the cytoplasm (original magnification , ϫ240). Diagnosis: Vaginal African histoplasmosis caused by Histo-plasma capsulatum var. duboisii in an African patient with HIV infection. The diagnosis was established by characteristic histopatho-logical findings (figures 1–3) and IgG Western blot, immu-nodiffusion, and PCR results. H. capsulatum var. duboisii, the causative agent of African histoplasmosis, is reported exclusively in Central and West Af-rica and in Madagascar [1, 2]. The natural habitat of H. cap-sulatum var. duboisii is in bird droppings and bat excrement. The seroprevalence of African histoplasmosis ranges up to 35% among cave guides, traders, and farmers living near bat caves [1]. It is thought that H. capsulatum var. duboisii enters the body through the lungs, although primary pulmonary infection has not been demonstrated. Infection occurs rarely via direct inoculation into the skin [3, 4]. The incubation period can vary from months up to several years after departure from regions in which the disease is endemic [1]. African histoplasmosis presents with granulomatous and suppurative lesions in cutaneous, subcutaneous, and osseous tissues, with local lymphadenopathy. The cutaneous manifestations include papular, nodular, ulcerative, ulceropolypous, eczematoid, and psoriasiform lesions. Progressive systemic dissemination with fever, rigor, and miliary lesions in the liver, the spleen, and (rarely) in the lungs have been reported [1, 4]. The histopathological characteristics of African histoplas-mosis are characteristic and distinct from those of American histoplasmosis. The typical lesions show clusters of multinu-cleated giant cells containing numerous oval, doubly contoured yeasts (8–15 mm in diameter), which have thicker walls and a greater diameter than H. capsulatum var. capsulatum (which are 2–4 mm in diameter). Diagnosis relies on characteristic histopathological findings in biopsy specimens. Confirmation by culture is possible, but it is difficult because of the long generation time (6–30 h) [4]. Antigen detection in serum and urine samples is a sensitive test Figure 3. Grocott methenamine silver stain of a biopsy specimen, showing multinucleated giant cells, polymorphonuclear granulocytes, and multiple ovoid yeasts (arrow) (original magnification, ϫ124). for H. capsulatum var. capsulatum. Serological tests often have negative results in patients with AIDS, but they are potentially useful for the diagnosis of African histoplasmosis, because H. capsulatum var. …