Unilateral Anteriorly Positioned Extrarenal Calyces Associated with Vascular Variations: A Case Report and Literature Review of a Rare Congenital Anomaly

Congenital anomalies primarily affect the upper urinary tract, with the extra-renal calyx (ERC) being a particularly rare anomaly first described by Eisendrath in 1925. Despite its identification nearly a century ago, fewer than fifty cases have been reported in the literature. This anomaly, which generally involves major calyces, is characterized by the displacement of calyces and the renal pelvis outside the renal parenchyma. Its exact etiology, however, remains unclear. It has been associated with a range of renal anomalies, including ectopic kidney, renal dysplasia, fusion abnormalities, and malrotations. During the dissection of a 59-year-old female cadaver, a unilateral ERC was revealed with vascular variations, including multiple renal arteries, one of which was twisted around the renal vein, accompanied by incomplete malrotation. ERCs are significant for clinical practice and should be considered by surgeons, as understanding such anatomical variations is critical for radiological assessments and surgical interventions. Early detection and monitoring can enhance patient outcomes.