Translocation renal cell carcinoma: lack of negative impact due to lymph node spread.

BACKGROUND: Pediatric renal cell carcinoma (RCC) is clinically distinct from adult RCC. Characterization of the unique biological and clinical features of pediatric RCC are required.
METHODS: A retrospective review and biological analysis of all RCC cases presenting to Cincinnati Children's Hospital Medical Center (CCHMC) in the last 30 years was undertaken. Cases were classified according to the recent World Heath Organization morphologic classification and according to TFE3/TFEB status. A literature review of pediatric TFE+ cases was performed.
RESULTS: Eleven cases of RCC with clinical data were identified in our institutional review as follows: 6 clear cell, 2 papillary, 2 translocation, and 1 sarcomatoid. Upon reanalysis, 1 papillary and 1 sarcomatoid were confirmed, 1 case was "unclassified", and 8 of 11 (72.7%) had features consistent with translocation morphology. Of these 8, all demonstrated immunoreactivity for TFE3 (7 patients) or TFEB (1 patient) protein. In 3 cases, cytogenetics was available, each demonstrating confirmatory MiTF/TFE translocations. Seven of 8 TFE+ RCC patients presented with TNM Stage III/IV disease. Literature analysis confirmed a significant increase in advanced stage presentation in pediatric TFE+ RCC compared with TFE- RCC. Fourteen of fifteen (93.3%) patients with TFE+ stage III/IV RCC due to lymph node spread (N+ M(0)) remain disease free with a median and mean follow-up of 4.4 and 6.3 years, respectively (range, 0.3-15.5).
CONCLUSIONS: Translocation morphology RCC is the predominant form of pediatric RCC, associated with an advanced stage at presentation. Patients with TFE+ N+ M(0) RCC maintain a favorable short-term prognosis after surgery alone. Young RCC patients should be screened for translocation morphology, and the screening information should be considered when debating adjuvant therapy.