Intrarenal Adrenocortical Adenoma Treated by Robotic Partial Nephrectomy with Adrenalectomy

Background: We present an intrarenal adrenocortical adenoma discovered incidentally after robot-assisted partial nephrectomy and total adrenalectomy for a suspicious renal mass. Current literature describes the rare occurrence of an adrenocortical adenoma arising from a renal–adrenal fusion. This case represents an uncommon, benign pathology that should be considered in the differential diagnosis of an enhancing renal mass. Case Presentation: The patient is a 62-year-old female found to have an enhancing mass at the anterolateral aspect of the upper pole of the right kidney concerning for renal-cell carcinoma. CT imaging was performed to work up a cause for hyperparathyroidism. During robot-assisted partial nephrectomy, the lesion was found to be partially adherent to the lateral limb of the right adrenal gland. Microscopic evaluation with Melan-A staining showed the mass to be of adrenal origin with benign features and lack of capsulation, indicating an adrenal adenoma arising from intrarenal ectopic adrenal rests. Conclusion: An intrarenal adrenal adenoma arising from ectopic adrenal tissue is a unique pathology that represents a benign differential diagnosis in the evaluation of an enhancing renal mass. However, it cannot be differentiated from renal-cell carcinoma based on cross-sectional imaging alone and requires postoperative pathologic assessment to confirm the diagnosis.