Incidental Adrenal Masses: A Case Report of an Adrenal Oncocytoma

A 59-year-old woman underwent an abdominal and pelvic computed tomography (CT) scan to rule out non-obstructive urolithiasis. The patient was asymptomatic, with the exception of occasional bilateral low back pain. A physical examination did not reveal any notable findings. The CT scan revealed the presence of an incidental solid left adrenal lesion, which displaced the body of the pancreas and the left kidney. The lesion measured 7 cm × 6.5 cm and exhibited a rounded morphology with well-defined margins. It showed progressive and heterogeneous contrast uptake. Additionally, magnetic resonance imaging (MRI) was performed, confirming the presence of an adrenal lesion with intense and heterogeneous hypersignal on T2. The lesion also demonstrated heterogeneous and persistent enhancement in a dynamic study. Furthermore, there were some indistinct and non-specific hypointense areas identified on both T1 and T2 sequences. The lesion exhibited moderately restricted diffusion. Although the imaging features were non-specific, there were no indications of invasion or distant metastasis, which made a benign large adrenal mass the most likely diagnosis. Non-functioning pheochromocytoma, lipid-poor adrenal adenoma, as well as metastasis or primary adrenal carcinoma, were considered differential diagnoses. The patient underwent an elective adrenalectomy, during which the identified lesion was completely resected. The patient's postoperative recovery was uneventful, and she was discharged three days after the procedure. Subsequent histopathological evaluation revealed an oncocytic neoplasm of the adrenal cortex - specifically, an oncocytoma.