SAT-472 - Adrenal Histoplasmosis Presenting as Bilateral Adrenal Nodules Mimicking Malignancy in A Filipino Patient

Adrenal histoplasmosis is a rare disease, accounting for < 1% of bilateral adrenal masses worldwide. It may cause significant morbidity and mortality if untreated. This represents only the second reported case in the Philippines.

We present a case of a 61-year-old man with Type 2 Diabetes Mellitus who presented with dyspnea, cough, weight loss, fatigue, and fever, initially treated as Pulmonary Tuberculosis and Interstitial Lung Disease. He was previously active and worked as a golf course developer with exposure to land excavation.

Chest CT incidentally revealed bilateral adrenal masses. Abdominal CT demonstrated a lobulated, peripherally enhancing hypo- to isodense mass with internal septations replacing the right adrenal gland (53×43×52 mm), with minimal surrounding fat stranding, and multiple enhancing nodules in the left adrenal gland, the largest measuring 13×10 mm. The right adrenal lesion showed imaging characteristics concerning for malignancy, with a pre-contrast attenuation of 31 HU, post-contrast attenuation of 90 HU, and delayed attenuation of 54 HU, with an absolute washout of 61.7% and relative washout of 40.1%.

PET-CT revealed hypermetabolic right adrenal gland mass with enhancing rim and internal septations, worrisome for a neoplastic process, and hypermetabolic nodules in the left adrenal gland, with the favoring adenoma. No other abnormal FDG uptake was seen.

Hormonal workup showed normal cortisol, renin, and 24-hour urine metanephrines and catecholamines, with low aldosterone and DHEAS. During hospitalization, the patient developed progressive weakness and persistent fever, which improved markedly following initiation of hydrocortisone.

Because of concern for adrenal cancer, adrenalectomy was initially considered. However, after multidisciplinary discussion, a definitive diagnosis was pursued due to its significant impact on management. Differential diagnoses at this time included primary adrenal malignancy, metastatic disease, lymphoma, and adrenal infection. CT-guided adrenal biopsy was done and revealed clusters of small uniform oval, narrow-based budding yeasts with eccentric acorn-shaped to ovoid nuclei intracellularly seen within histiocytes, characteristic of Histoplasmosis. No malignant cells were seen. The patient was then started on Itraconazole and was discharged well with steroids and Itraconazole.

After six months of therapy, he had significant weight gain and complete resolution of symptoms, allowing return to work and normal activities.

Adrenal infections are an overlooked cause of adrenal dysfunction. Adrenal histoplasmosis can cause adrenal insufficiency with significant morbidity and mortality if unrecognized. This case highlights the importance of a multidisciplinary approach and consideration of atypical etiologies, including disseminated fungal infections, in appropriate clinical settings.

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