A Rare Renal Cell Carcinoma Associated with Xp11.2 Translocation/TFE3 Gene Fusion: Case Report of 8 Cases and Review of the Literature

XP11.2 translocation TFE3 gene fusion renal cell carcinoma (RCC) is enlisted as a rare subtype of RCC by WHO in 2004. This type of Tumor was previously considered a pediatric tumor predominantly but is now invariably found in adult and older patients. The article investigates the clinical manifestation, pathological features, diagnosis criteria, and treatment of this rare subtype of RCC. We collected the clinical data of eight patients confirmed as XP11.2 TFE3 RCC admitted in the First affiliated hospital of Chongqing Medical University from August 2015 to November 2018, and a retrospective analysis of these data was conducted. There were three male, five female patients, the average age of 33.25 years old, ranging from 5 years old to 62. Six patients were asymptomatic and diagnosed incidentally, one of them complained of hematuria and back pain for three months, and another patient complained just back pain for four months. After hospital admission, transabdominal ultrasonography, CT scan, and MRI imaging were done on all the patients. The tumor sizes of 2 patients were more than 7cm; 3 patients were 5-6 cm, and the rest three patients were below 4cm. One Patient got an Open Radical Nephrectomy for the right kidney and Right Ureterectomy. Four patients went through a Radical nephrectomy, and partial nephrectomies were done in the rest three patients. All the removed tumor samples were analyzed using pathology and immunohistochemistry assays. The results showed that all samples had renal carcinoma cells, with positive CD10 and TFE3 staining. Other parameters varied from each other. One postoperative Patient got both chemotherapies and targeted therapy; 3 patients were treated with Interferon but changed to thymopentin due to adverse effects. Only one Patient got thymopentin, and the rest three patients did not need any adjuvant therapy. Follow-up was done on all patients from 6 months to 40 months. Except for one patient who died of lung metastasis at 16 months after surgery, no disease progression occurred in those patients. The imaging findings are atypical, constantly varying among different patients with various tumor morphologies. So far, the golden standard of diagnosis is postoperative pathology and immune histochemistry. Radical or partial nephrectomy combining with renal lymph node clearance should be performed if metastasis of lymph nodes occurs. Proper adjuvant therapy, including chemotherapies, targeted therapy, and immune therapy, should be applied when needed. To maintain a risk-free life, follow-up must be done every 3 to 6 months.