The Vanishing Adrenal Glands: A Transient Regression of Adrenal Lymphoma After a Single Dose of 1 mg Dexamethasone

OBJECTIVE: Dexamethasone is a known treatment for lymphoma, but the potency and rapidity of its effect have not been recognized. We present a case of bilateral adrenal lymphoma that significantly reduced in size after a single dose of dexamethasone. METHODS: We present the clinical course and investigations, including adrenocorticotropic hormone, cortisol, short synacthen test, computed tomography (CT), and adrenal biopsy results. RESULTS: A 52-year-old man had a fall and was incidentally found to have bilateral adrenal masses (left, 6 cm; right, 5 cm) on CT. His adrenal function tests included plasma metanephrines (normetanephrine, 830 pmol/L [normal, <1180]; metanephrine, <100 pmol/L [<510]; 3-methoxytyramine, <100 pmol/L [<180]); aldosterone, 270 pmol/L( 90-700); and random cortisol, 230 nmol/L (160-550). An overnight dexamethasone suppression test with 1 mg of dexamethasone showed cortisol of <28 nmol/L (0-50). A repeat CT scan 8 days thereafter showed adrenal masses of 4.5 and 3.5 cm on the left and right, respectively. He had a follow-up CT scan 3 months later that showed adrenal lesions measuring 8 cm (left) and 9 cm (right). He subsequently presented with fatigue and dizziness. Morning cortisol of 201 nmol/L (160-550) with adrenocorticotropic hormone of 216 ng/L (10-30) indicated primary adrenal insufficiency. Mineralocorticoid and glucocorticoid replacement therapy commenced. An adrenal biopsy showed abnormal enlarged B cells, consistent with a diagnosis of diffuse large B-cell lymphoma. CONCLUSION: A diagnosis of lymphoma should be considered when adrenal lesions shrink following even a single low dose of dexamethasone administered as a part of a diagnostic test.