Congenital mesoblastic nephroma: a case report and literature review

Abstract Background Congenital mesoblastic nephroma (CMN) is a rare entity of congenital kidney neoplasm in neonates. It encompasses three histological variants: mixed, classic, and cellular, with the third associated with a poorer prognosis. Due to its resemblance to other more common pediatric kidney tumors, CMN remains diagnostically challenging for pathologists. This report presents an incidental finding of CMN in the right kidney of a 2-month-old infant. Case presentation A 2-month-old male infant initially presented with persistent vomiting. A clinical examination revealed a palpable mass in the right loin, prompting further investigation. Ultrasound imaging detected a well-defined, vascular solid mass compressing the upper pole of the right kidney. A subsequent computed tomography scan confirmed a renal mass extending beyond the parenchyma into the perinephric space. The patient underwent a right open radical nephrectomy accompanied by lymph node dissection. The histopathological analysis identified the mass as a mixed variant of CMN without lymph node involvement. Post-operatively, the patient’s recovery was satisfactory. Literature review In a literature review for identifying congenital mesoblastic nephroma, 10 cases were randomly reviewed, seven (70%) of them were female, while only three (30%) were male. The age range spanned from a preterm infant born at 30 weeks of gestation to a 17-day-old male infant. Conclusion The CMN is a rare congenital tumor that may be asymptomatic and detected incidentally. Open radical nephrectomy can be an effective treatment with a minimal risk of recurrence.