Crossed-fused renal ectopia: exploring the concerns of the  asymptomatic :

Mathew Y.  Kyei; Geoffrey  Birikorang

doi:10.46829/hsijournal.2025.6.7.1.1235-1237

Mathew Y. Kyei Department of Surgery and Urology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Accra, Ghana
Geoffrey Birikorang Department of Surgery, Korle Bu Teaching Hospital, Accra, Ghana

DOI: https://doi.org/10.46829/hsijournal.2025.6.7.1.1235-1237

Keywords: crossed-fused renal ectopia, Fusion anomalies of kidney, incidental, CT angiography, patient concerns

Abstract

Introduction: Crossed-fused renal ectopia is an anomaly where the kidneys are fused and located on the same side of the midline, with the opposite side empty. This was first described in 1654 by Dominicus Panarolus [1,2]. Another theory indicated that the anomaly may be due to arrest of kidney ascent, causing the kidneys to remain in the pelvis or meet on one side with subsequent fusion. Abnormal position of the umbilical artery influencing the cephalic migration of the kidneys to the contralateral side following a path of least resistance has also been proposed to lead to cross-fused renal-ectopia [3].
It becomes a single renal mass when there is fusion, which occurs in 90% of the cases. However, the urinary collecting systems remain separate. Wilmer is credited with first categorising the fusion anomalies of the kidney (1938).
McDonald and McClellan 1957 modified the classification to include crossed ectopia with fusion, crossed ectopia
without fusion, solitary crossed ectopia and bilateral crossed ectopia [4]. The current classification used comprises (i) Unilateral fused kidney (inferior ectopia), (ii) Sigmoid or S-shaped kidney, (iii) Lump kidney, (iv) L
shaped kidney, (v) Disc kidney and (vi) Unilateral fused kidney (superior ectopia) [4]. The current case is a unilateral fused kidney (inferior ectopia).