Ectopic Kidney Masquerading as a Pelvic Mass: A Case Report

Renal ectopia is a congenital anomaly caused by abnormal migration of the kidneys during the process of embryogenesis. Under typical development, the kidneys ascend to the lumbar region during the early gestational period. A failure in this process can result in ectopic kidneys, most commonly found in the pelvis. Although often asymptomatic, pelvic kidneys can be complicated by pelviureteric junction obstruction (PUJO), infection, reflux, or malrotation in a few cases. We present a rare case of a pelvic kidney with PUJO presenting as a lower abdominal mass in an elderly female. A 60-year-old female presented to our urology clinic with progressive lower abdominal fullness and vague discomfort for several months. Clinical examination revealed a firm, non-tender mass measuring 15 × 8 cm in the hypogastric and iliac regions. Blood investigations and renal function tests were within normal limits. Contrast-enhanced CT urography revealed a grossly hydronephrotic left pelvic kidney with parenchymal thinning and no contrast excretion. No calculi or masses were identified. A diethylenetriamine pentaacetic acid (DTPA) renogram confirmed severely impaired function of the ectopic kidney. The patient underwent cystoscopy with ureteric catheterization, followed by left nephrectomy. Histopathological examination confirmed chronic pyelonephritis in the hydronephrotic kidney. A pelvic kidney is an uncommon congenital anomaly identified in a small proportion of births. PUJO is one of the most common causes of hydronephrosis in ectopic kidneys. Detailed imaging and functional studies are essential for diagnosis and management. Delayed presentation in adults highlights the need to consider renal ectopia in differential diagnosis. This case emphasizes the importance of recognizing ectopic kidneys in adults presenting with abdominal masses. Timely imaging and functional assessment aid in appropriate surgical decision-making, especially in non-functioning kidneys where nephrectomy prevents long-term complications.