OBJECTIVE: To determine the frequency and distribution of primary renal tumors diagnosed in a pediatric oncology unit in children younger than 1 year and identify their clinical and histopathological characteristics, the treatment used, and outcomes. MATERIAL AND METHODS: We retrospectively reviewed the medical records of infants with primary tumors of the kidney diagnosed between January 1972 and February 2003. RESULTS: A total of 137 tumors were diagnosed in our unit during the period studied. Of these, 25 (18.2 %) occurred in infants aged less than 1 year. There were 17 boys and 8 girls. The most prevalent tumor in this age group was Wilms' tumor (WT) in 15 patients, followed by mesoblastic nephroma (MN) in 9 patients and rhabdoid tumor in 1 patient. The mean age at diagnosis of WT was 4.8 months (range: 1 day-11 months), with a median of 5.03 months. The median age at diagnosis of MN was 1 day (range: 1 day-3 months). Presenting symptoms consisted of abdominal mass in 20 patients, hematuria in 4 patients and intestinal pseudo-occlusion (MN) in 1 patient. High blood pressure was found in 12 of the 25 patients. Among the 15 WT, 9 were stage I, 1 was stage II, one was stage III, 2 were stage IV, and 1 was stage V. One patient died before surgery. Overall survival at 5 years was 0.67 (SE 0.12) for WT and 0.89 (SE 0.1) for MN, respectively, with a mean follow-up of 290 months. CONCLUSIONS: MN was more frequent than WT in infants aged less than 6 months. The first-line therapy in these patients is surgery since this type of tumor shows little chemosensitivity and chemotherapy is poorly tolerated in infants.
OBJECTIVE: To determine the frequency and distribution of primary renal tumors diagnosed in a pediatric oncology unit in children younger than 1 year and identify their clinical and histopathological characteristics, the treatment used, and outcomes. MATERIAL AND METHODS: We retrospectively reviewed the medical records of infants with primary tumors of the kidney diagnosed between January 1972 and February 2003. RESULTS: A total of 137 tumors were diagnosed in our unit during the period studied. Of these, 25 (18.2 %) occurred in infants aged less than 1 year. There were 17 boys and 8 girls. The most prevalent tumor in this age group was Wilms' tumor (WT) in 15 patients, followed by mesoblastic nephroma (MN) in 9 patients and rhabdoid tumor in 1 patient. The mean age at diagnosis of WT was 4.8 months (range: 1 day-11 months), with a median of 5.03 months. The median age at diagnosis of MN was 1 day (range: 1 day-3 months). Presenting symptoms consisted of abdominal mass in 20 patients, hematuria in 4 patients and intestinal pseudo-occlusion (MN) in 1 patient. High blood pressure was found in 12 of the 25 patients. Among the 15 WT, 9 were stage I, 1 was stage II, one was stage III, 2 were stage IV, and 1 was stage V. One patient died before surgery. Overall survival at 5 years was 0.67 (SE 0.12) for WT and 0.89 (SE 0.1) for MN, respectively, with a mean follow-up of 290 months. CONCLUSIONS: MN was more frequent than WT in infants aged less than 6 months. The first-line therapy in these patients is surgery since this type of tumor shows little chemosensitivity and chemotherapy is poorly tolerated in infants.