A Rare Primary Adrenal Malignancy Manifesting as a Hemorrhagic Mass: Case Report and Literature Review

Primary adrenal extranodal natural killer/T‐cell lymphoma (ENKTL) is an exceptionally rare, aggressive malignancy with fewer than 10 cases worldwide. We describe a 55‐year‐old man with diabetes mellitus and benign prostatic hyperplasia who presented with progressive left‐sided abdominal pain and a 17‐kg unintentional weight loss over 4 months. Imaging showed a 4.9‐cm left adrenal mass with hemorrhagic features, initially presumed to be spontaneous adrenal hemorrhage. Endocrine evaluation excluded functional adrenal tumors, and surgical management required conversion from laparoscopic adrenalectomy to open resection due to superior mesenteric vein (SMV) involvement. Histopathological and immunophenotypic confirmed non‐nasal ENKTL (CD3+, CD56+, granzyme B+, perforin+, and Epstein–Barr virus‐encoded RNA EBER+). Postoperative 18 F‐FDG PET/computed tomography (CT) demonstrated residual disease; steroid, methotrexate, ifosfamide, L‐asparaginase, and etoposide (SMILE) chemotherapy achieved a marked complete metabolic response after six cycles—one of the most significant documented responses in primary adrenal NK/T‐cell lymphoma. This case highlights diagnostic challenges of primary adrenal lymphoma (PAL), the need for histopathological confirmation in atypical masses, and suspicion for hematological malignancies with systemic symptoms and adrenal lesions.