Translocation Renal Cell Carcinoma in a Child Previously Treated for Infantile Fibrosarcoma.

We report a child who developed a TFE3/Xp11.2 translocation renal cell carcinoma (RCC) when he was 3 years and 3 months old, after previous treatment for infantile fibrosarcoma (IFS). When he was 3 months old, a left axilla mass has been detected, which was tan and solid, was 1.5 cm in greatest dimension, and composed of sheets of spindle cells that was positive for vimentin and fibronectin. Fluorescence in situ hybridization showed positive result in ETV6 gene rearrangements. The final diagnosis was IFS. After surgery and chemotherapy, he remained disease-free until 3 years; later, he was detected to have a tumor in right kidney which measured 2.5 × 2 × 1.5 cm. The tumor comprised clear-cell features that were arranged in papillary and adenoid architecture. The tumor cells were positive for TFE3 and CK. The diagnosis was TFE3/Xp11.2 translocation RCC. Previous research has reported that the radio/chemotherapy for the first tumor might be involved in the pathogenesis of translocation RCC. In our report, this is the first time the IFS is included in the disease spectrum which can cause secondary translocation RCC.