A Longitudinal Case Study of Renal Cyst Progression and Regression in Trisomy 13

Trisomy 13 is a chromosomal disorder frequently associated with congenital anomalies, including polycystic kidney disease (PKD). Although the link between trisomy 13 and PKD is recognized, the timing and progression of renal cyst development remain unclear. We report a male neonate with trisomy 13 in whom we performed serial renal ultrasounds, enabling real‐time monitoring of PKD progression. Prenatal and immediate postnatal imaging revealed no renal abnormalities. However, progressive microcystic changes became evident by day 86, peaked around day 169, and subsequently regressed by day 434. Despite transient kidney enlargement, renal function remained stable at chronic kidney disease stage 2. This case demonstrates that regular and serial postnatal renal ultrasound is necessary to detect and manage PKD progression in trisomy 13. We recommend structured renal follow‐up to enable early intervention and improve clinical care in these patients.