Pancake kidney in infant: A case report with literature review.

Pancake kidney (PK) is a rare anomaly, accounting for only 2% of all cases of fused kidneys. In this condition, the renal pelvis faces anteriorly, the ureters do not cross, and the collecting systems of the kidneys are separate, with no communication between the 2 sides. The PK may be associated with various urinary tract defects and anomalies in other organs. This report presents a case of an infant diagnosed with pelvic PK accompanied by ureteropelvic junction (UPJ) obstruction and an undescended right testis, representing an exceedingly rare combination of conditions. A 2-month-old male infant presented with an absent right testis. Ultrasound identified the right testis in the inguinal canal and revealed pelvic kidneys with malrotation. The right kidney showed mild hydronephrosis, while the left exhibited moderate hydronephrosis consistent with left UPJ obstruction and PK. A retrograde pyelogram confirmed mild UPJ stenosis, prompting the placement of a left JJ stent. The infant underwent right-sided orchidopexy and was scheduled for 6-month follow-ups. A review of 10 reported PK cases from the past decade revealed that 7 patients (70%) were male, and 3 (30%) were female, indicating a male predominance. The age at diagnosis ranged from 12 to 90 years. The retroperitoneal space was the site of PK in 2 cases (16.7%), with 1 case coexisting with rectosigmoid carcinoma. The PK may coexist with conditions such as UPJ obstruction and undescended testes. If asymptomatic, it can be managed conservatively, with monitoring to prevent complications.