Adrenal Histoplasmosis in Immunocompetent Patients Presenting as Adrenal Insufficiency

Histoplasmosis is an infectious disease caused by the dimorphic fungus Histoplasma capsulatum, endemic in central and eastern states of United States, South America and Africa. India is considered to be non-endemic area for histoplasmosis. Disseminated histoplasmosis may affect almost all systems. Disseminated histoplasmosis with asymptomatic adrenal involvement has been described in immunocompromised patients; whereas isolated adrenal involvement with adrenal insufficiency as the presenting manifestation of the disease is rare.

Twelve patients from a non-endemic area with adrenal histoplasmosis, who were immunocompetent and diagnosed as adrenal histoplasmosis by cytology/histopathology between January 2012 to December 2014 were studied. 18F-FDG PET/CT (fluorodeoxyglucose positron emission tomography/computed tomography) was used to assess the extent of involvement.

There were a total of 12 immunocompetent males (mean age: 56.9 years). Ten patients had bilateral adrenal involvement and two had a unilateral left adrenal mass. All the patients had histopathologically/cytologically proven adrenal histoplasmosis. Two patients had simultaneous histoplasmosis of other sites, one in the epiglottis and the other in the alveolus. 18F-FDG PET/CT was performed in 10 patients showing high FDG uptake in the adrenals. All these patients received Amphotericin B and/or Itraconazole treatment that led to symptomatic improvement.

A diagnosis of invasive fungal infection requires a high index of suspicion, especially in immunocompetent patients who present with nonspecific symptoms, clinical signs, laboratory and radiological features that can resemble adrenal neoplasms. Clinical specimens must be sent for cytopathology/histopathology together with fungal culture for a definite diagnosis and appropriate management.