Ectopic adrenal nodular hyperplasia mimicking right upper polar renal cell carcinoma: a case report and literature review.

Ectopic adrenal tissue refers to adrenal tissue appearing in an abnormal anatomical location, typically originating from residual adrenal tissue or ectopic structures during embryonic development. As a rare congenital anomaly, its atypical anatomical position and diverse clinical manifestations often pose diagnostic challenges. This report describes a 46-year-old male patient who presented with intermittent hematuria for two weeks. Enhanced CT of the kidneys revealed a protruding nodule at the margin of the right renal pole, measuring approximately 1.6 cm and showing relatively uniform enhancement, suggesting a hypo vascular mass lesion. Enhanced MRI of both kidneys showed a nodule at the right renal pole, consistent with a mass due to insufficient blood supply. Based on imaging findings and clinical symptoms, a preliminary diagnosis of right renal carcinoma (RCC) was made, leading to a laparoscopic partial nephrectomy. Postoperative pathology confirmed the lesion as ectopic adrenal tissue. This case highlights that ectopic adrenal tissue within the kidney may mimic renal cell carcinoma in both clinical presentation and imaging characteristics, underscoring the need for enhanced differential diagnosis between these two conditions in clinical practice.