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.