SAT-487 - A Case of Bilateral Adrenal Gland Metastases of Unknown Primary Cancer

Background: The differential for bilateral adrenal masses is broad: hyperplasia, infection, adenomas, primary malignancies and metastases. The adrenal glands are among the most common sites for metastases, with melanomas, breast and lung carcinomas being among the most common primary tumors.
Clinical Presentation: A 46-year-old man with type 1 diabetes endorsed 1 month of lower abdominal pain and fatigue to his endocrinologist. CT abdomen/pelvis revealed bilateral multi-cystic lesions of the adrenal glands (right 7.9 x 6.6 cm, left 9.3 x 7.3 cm). Initial lab work included: aldosterone < 4.0 ng/dl, renin 1.5, ACTH 95.6, DHEA-SO4 45.5 ug/dl, afternoon cortisol 11.7 ug/dl, serum metanephrine < 0.20 nmol/L, normetanephrine 1.1 nmol/L. Low DHEA-SO4 and high ACTH with compatible symptoms suggested adrenal insufficiency and the patient was started on hydrocortisone 15mg daily with improvement in fatigue. FDG-PET revealed intensely hypermetabolic bilateral adrenal masses with hypermetabolism in the proximal gastric body and an indeterminate millimetric lung nodule. Left adrenal mass biopsy revealed poorly differentiated carcinoma of possible GI primary, with immunostaining of the tumor strongly suggesting against adrenocortical carcinoma and pheochromocytoma. A subsequent endoscopic biopsy of a gastric erosion was positive for poorly differentiated carcinoma, similar to the pathology of the adrenal mass. Thus, the patient started FOLFOX and pembrolizumab for presumed GI primary. Later molecular profiling via Caris MiSeek of the biopsy revealed 66% likelihood of non-small-cell lung cancer with genomic test suggesting 1% likelihood of stomach cancer. FOLFOX was stopped in favor of pembrolizumab monotherapy. A repeat CT abdomen/pelvis was completed and showed interval enlargement of the adrenal masses, to 10.1 cm (right) and 11cm (left). The patient’s hydrocortisone has been uptitrated to 15mg in the morning and 10mg in the afternoon.

Conclusion: In this case of bilateral polycystic adrenal gland masses of unclear etiology, originally, an initially broad differential was narrowed, but not closed, with biopsy. Genetic testing was crucial to making the diagnosis.

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