Bilateral adrenal diffuse large B-cell lymphoma masquerading as bilateral adrenal metastases: a rare presentation diagnosed by endoscopic ultrasound-guided fine-needle biopsy

Bilateral adrenal diffuse large B-cell lymphoma (DLBCL) is an exceedingly rare entity. Presentation as bilateral adrenal masses without an identifiable extra-adrenal primary poses a formidable diagnostic challenge, frequently mimicking adrenal metastases or primary adrenal malignancy. A 70-year-old normotensive, non-diabetic male presented with a one-month history of weight loss, generalized dull abdominal pain, and anorexia. Contrast-enhanced computed tomography (CECT) revealed bilateral adrenal masses (right 56 × 28 × 55 mm; left 61 × 30 × 54 mm) with imaging characteristics indistinguishable from metastatic disease. Extensive workup—including CT of the neck and chest, colonoscopy, and biochemical adrenal profiling—failed to identify a primary extra-adrenal malignancy or hormonal excess. Endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) using a 22-gauge needle provided tissue confirming diffuse large B-cell lymphoma (DLBCL) with CD20 and PAX-5 positivity. The patient was referred to oncology and commenced on rituximab-based chemotherapy. This case underscores the indispensable role of EUS-guided tissue sampling in the evaluation of bilateral adrenal masses when non-invasive workup is inconclusive. Early tissue diagnosis of adrenal DLBCL is critical, as it is a potentially curable disease amenable to immunochemotherapy rather than surgery.