Disseminated cutaneous histoplasmosis in an immunocompetent adult

Abstract

Histoplasmosis, a systemic mycosis caused by the dimorphic fungus Histoplasma capsulatum var capsulatum and Histoplasma capsulatum var duboisii is endemic to many parts of the world. The clinical manifestations range from acute or chronic pulmonary infection to a progressive disseminated disease. After initial exposure to the fungus, the infection is self-limited and restricted to the lungs in 99% of healthy individuals. The remaining 1%, however, progress to either disseminated or chronic disease involving the lungs, liver, spleen, lymph nodes, bone marrow or rarely, the skin and mucous membranes. Mucocutaneous histoplasmosis is frequently reported in patients with acquired immune deficiency syndrome (AIDS), but it is rare in immunocompetent hosts. A 60-year-old male presented with asymptomatic swelling of the hard palate and crusted papules and nodules over the extremities, face and trunk. Clinically, the diagnoses of cutaneous cryptococcosis versus histoplasmosis was considered in this patient. A chest X-ray revealed hilar lymphadenopathy. Enzyme-linked immunosorbent assay (ELISA) for human immunodeficiency virus (HIV) was nonreactive. Skin biopsy revealed multiple tiny intracellular round yeast forms with a halo in the mid-dermis. Culture of the skin biopsy in Sabouraud's dextrose agar showed colonies of Histoplasma capsulatum. Despite an investigation including no evidence of underlying immunosuppression was found, he was started on IV amphotericin-B (0.5 mg/kg/day). However, the patient succumbed to his disease 2 days after presentation. We report a rare case of disseminated cutaneous histoplasmosis in an immunocompetent individual.

Keywords: Histoplasmosis; histoplasma capsulatum; immunocompetent; mucocutaneous lesions.

Figure 1

(a-b) Multiple skin-colored papules and nodules over the chest and face

Figure 2

Irregular firm and indurated nodular growth on the hard palate

Figure 3a

Multiple intracellular rounded yeasts surrounded with the halo in dermis, ×400 H and E

Figure 3b

Multiple intracellular rounded yeasts surrounded with the halo in dermis, ×400 PAS stain(3b)

Figure 3c

Multiple intracellular rounded yeasts surrounded with the halo in dermis, ×400 GMS (3c)

Figure 4

Culture from the skin tissue specimens grew white cottony colonies of histoplasmosis

Figure 5

Test of dimorphism was positive suggestive of Histoplasma capsulatum