Progressive disseminated histoplasmosis in an immunocompetent adult: A case report

Abstract

Histoplasmosis is a systemic fungal infection caused by Histoplasma capsulatum which occurs endemically in some parts of the world like North and Central America particularly in Mississippi and Ohio River valleys, but is uncommon in India. Progressive disseminated form of histoplasmosis (PDH) usually occurs in the immune-compromised hosts especially in HIV positive population. In PDH any organ can be involved like lung, liver, spleen, brain, adrenals etc. Involvement of oral cavity and buccal mucosa in PDH is common but pharyngeal involvement is rare. We here report a case of progressive disseminated histoplasmsosis with pharyngeal involvement in an immunocompetent male from non-endemic area. This case presented to us with history of long duration fever and we found the etiology by giving due significance to a trivial symptom and thorough evaluation of the same. Etiology was found as disseminated histoplasmosis, which is not a common disease. We treated him initially with amphotericin-B then subsequently with itraconazole for one year. He recovered fully over the period of one year with the given treatment. This case report emphasizes that disseminated histoplasmosis should be considered one differential diagnosis in case of long duration of fever, even in an immunocompetent patient. It also emphasizes that in evaluation of a case of long duration of fever, even a trivial symptom is very crucial, which may direct towards the diagnosis.

Keywords: Histoplasma capsulatum; Progressive disseminated histoplasmosis; fever of unknown origin; immunocompetent; pharyngeal histoplasmosis.

Figure 1.

FDG-PET scan showing significantly increased FDG uptake in the posterior pharyngeal wall.

Figure 2.

Yeasts of histoplasma are seen extracellularly as well as inside the giant cells under 40× magnification in the biopsy specimen taken from pharynx (Periodic acid Schiff staining with diastase).

Figure 3.

Yeast form of histoplasma is seen under 40× magnification in the biopsy specimen taken from pharynx (Periodic acid Schiff staining with diastase).

Figure 4.

Nodular skin lesion over chest developed after starting amphotericin B.