Congenital mesoblastic nephroma: report of two cases

Introduction: Congenital mesoblastic nephromas (CMN) are rare renal tumors that primarily affect infants under 6 months of age, typically with a favorable prognosis.

Clinical case: We present two clinical cases of CMN with hematuria and abdominal mass as initial clinical manifestations. The first case involves a 2-month-old infant who developed arterial hypertension during hospitalization, while the second patient, a 6-month-old, presented with postoperative tachycardia. Both underwent radical nephrectomy, with tumor-free surgical margins. Histopathological analysis revealed a mixed-type CMN in the left kidney of the first patient and a cellular-type CMN in the right kidney of the second infant. Both patients were discharged without complications and remain under follow-up.

Conclusions: CMN are low-grade malignant neoplasms with an excellent prognosis following nephrectomy. However, close follow-up is essential to monitor for recurrence and cardiovascular complications, particularly in the cellular and mixed variants.