Relative frequency of non-Wilms renal tumours in children: an institutional experience from a national tertiary referral centre in Malaysia.

PURPOSE: International protocols for paediatric renal tumours are largely based on Western data with Wilms tumour (WT) accounting for more than 90% of cases. We aimed to evaluate the relative frequency of WT and Non-Wilms Renal Tumours (NWRTs) in a diverse Asian cohort in Malaysia.

METHODS

A retrospective review was conducted of all primary paediatric renal tumours treated at a national tertiary referral centre from 2015 to 2024. Diagnosis was confirmed via post-operative histopathology.

RESULTS

Of 95 children (median age 29 months), all were Asian descent (73.7% Malay, 9.5% Chinese, 6.3% Indian). WT accounted for only 68.4% of cases, while NWRTs accounted for 31.6%. Among NWRTs, 63.3% were malignant, primarily clear cell sarcoma of the kidney (CCSK, n = 7) and renal cell carcinoma (RCC, n = 4). In the classic WT age range (6-84 months), WT prevalence was only 75.6%, with CCSK representing 9.0%. Congenital mesoblastic nephroma (CMN) predominated in infants < 6 months (71.4%), while RCC was exclusively seen in children > 84 months (40.0%).

CONCLUSION

The substantial proportion of malignant NWRTs observed in this institutional cohort highlights potential risks of neoadjuvant chemotherapy without histological confirmation. Histopathological diagnosis via percutaneous core-needle biopsy or primary surgery may be highly considered in similar clinical settings.