SAT-221 50-Year-Old Fungus Suddenly Flourishes in Adrenal Glands: A Case of Sudden-Onset Bilateral Adrenal Masses Due to Latent Disseminated Histoplasmosis

Histoplasma capsulatum is endemic to Africa, Asia, Central and South America, and within the US, to the Ohio and Mississippi River Valley. Disseminated histoplasmosis is less commonly seen in immunocompetent individuals, who usually present with asymptomatic self-limited acute pneumonitis. Time to involvement of the adrenals is unknown. Adrenal insufficiency occurs in 45% of cases involving the adrenals, and is thought to be irreversible even in patients in remission. A 76-year-old man with no significant past medical history was incidentally found to have large bilateral adrenal masses during routine surveillance of a 7 mm pulmonary nodule on annual Chest CT, which showed normal adrenal glands the year prior. He was asymptomatic. A lifetime non-smoker native to California, whose only significant travel history was in his 20s to Ecuador and Puerto Rico, areas endemic to Histoplasma. Abdominal CT showed large bilateral adrenal masses with intermediate density and low washout values (right: 4.9 cm, HU 45, absolute washout 30%; left: 4.8 cm, HU 30, absolute washout 25%). On exam, vital signs were stable with normal orthostatics. Labs revealed normocytic anemia, normal chemistry panel, normal cortisol after 1-mg dexamethasone overnight test 2.6 mcg/dL (n<5 mcg/dL), plasma metanephrine <0.10 nmol/L (n <0.50 nmol/L), plasma normetanephrine 0.89 nmol/L (n <0.90 nmol/L), aldosterone 4.0 ng/dL (n <31 ng/dL), PRA 2.0 ng/ml/hr (n 0.5-4 ng/ml/hr) and random free cortisol 0.38 ug/dL (n 0.022-0.254ug/dL). HIV antigen and antibody, and Histoplasma urinary antigen were negative. Left adrenal mass biopsy revealed necrotizing granulomatous inflammation with fungal culture revealing budding yeast morphologically consistent with Histoplasmosis, with DNA probe confirming Histoplasma capsulatum. Treatment with itraconazole was initiated and the patient is tolerating the treatment well. To our knowledge, this is the first case demonstrating rapid development of large bilateral adrenal masses within a year due to latent disseminated histoplasmosis in an asymptomatic individual, which highlights the need for appropriate testing in patients with known exposure or travel history to endemic areas, regardless of time since exposure. 1.Singh M, Chandy DD, Bharani T, Marak RSK, Yadav S, Dabadghao P, et al. Clinical outcomes and cortical reserve in adrenal histoplasmosis- a retrospective follow-up study of 40 patients. Clin Endocrinol 2019 Jan 17