Introduction and importanceCongenital mesoblastic nephroma is a common benign renal tumor that mainly affects infants below the age of six months (Daskas et al., 2002). Identifying the pathology type is crucial for determining the appropriate plan of action and predicting the patient's prognosis.Case presentationA one-day-old Hispanic neonate was referred for surgical evaluation after detecting a LUQ mass. Ultrasound imaging revealed a heterogenous solid mass that infiltrated the hilum of the left kidney. The patient underwent a left radical nephrectomy, and the pathology results indicated that the mass was consistent with the classic type of congenital mesoblastic nephroma. The patient will be closely monitored by nephrology with frequent abdominal ultrasounds.Clinical discussionThe case describes a one-day-old female baby with an asymptomatic LUQ abdominal mass, which was diagnosed as mesoblastic nephroma. The baby was born full-term with no significant medical history, and after experiencing hypertensive episodes, she underwent a left radical nephrectomy to remove the tumor. Pathology confirmed mesoblastic nephroma, classic type, and the patient was diagnosed with stage I disease since the tumor was entirely resected with no renal vessel involvement. Follow-up ultrasounds were recommended to monitor for recurrence, and chemotherapy may be considered if recurrence occurs (Pachl et al., 2020). Calcium and renin levels should also be monitored (Bendre et al., 2014).ConclusionAlthough congenital mesoblastic nephroma is typically benign, patients require ongoing monitoring for potential paraneoplastic syndromes. Furthermore, certain types of mesoblastic nephroma can progress to malignancy, necessitating close follow-up during the first few years of life.