Oncocytoid renal cell carcinoma after neuroblastoma: A report of four cases of a distinct clinicopathologic entity

Four children who developed oncocytoid renal cell carcinoma (RCC) after neu roblastoma are reported. One patient had multiple, bilateral RCCs. The mean age at time of diagnosis of RCC was 8.8 years (range, 5-13 years). The mea n interval between neuroblastoma and RCC was 7.15 years (range, 3.1-11.5 ye ars). The histologic findings of these RCCs did not fit within the spectrum of known renal epithelial neoplasms. Most of the neoplastic cells in all c ases had eosinophilic, oncocytoid cytoplasm and were arranged in solid and papillary growth patterns. A subset of cells with reticular cytoplasm was a lso present. Immunohistochemical studies demonstrated keratins 8 and 18 in all neoplasms and keratin 20 in two cases. DNA ploidy analysis revealed tha t two of three neoplasms assessed were aneuploid. Cytogenetic studies revea led 45, XX, add or dup (7)(q32q36) in one neoplasm, and 83-89, XXXX, -1,-3, del (3)(q11.1q2?1), der(4)t(4;?22) (q32;q11.2), -14, -22 in a second tumor . Microsatellite polymerase chain reaction analysis detected no abnormaliti es in one neoplasm and allelic imbalance of chromosomes 2p31-32.2, 8p22, 9p 22-24, 13q22 20q13, and 22q11 in a second tumor. In case 4, two different R CCs excised 6 months apart were analyzed. The initial neoplasm showed allel ic imbalance of chromosomes 2q31-32.2, 5q22, 5q31, 10p13-14, 13q22, 14q31, and 20q13. The subsequent neoplasm showed allelic imbalance of chromosomes 3p21.3, 14q31, and 20q13. The common presence of 14q31 and 20q13 abnormalit ies suggests that these two neoplasms were genetically related. In aggregat e, these findings are distinctive, are not found in known types of RCC, and support the morphologic impression that oncocytoid RCC after neuroblastoma is a distinct clinicopathologic entity.