Report of 6 cases of Xp11.2 translocation renal cell carcinoma and literature review

Abstract

Objective To explore the clinical and pathological characters of Xp11.2 translocation renal cell carcinoma. Method We screened patients of renal cell carcinoma of PUMCH between Jan. 2011 and Dec. 2015, 6 patients with Xp11.2 translocation renal cell carcinoma were found. There were 2 males and 4 females, with average age of 39 (ranging from 16 to 73 years old). Diameter of tumor ranged from 1.9cm to 19.0cm, and 9.6cm in average. Among which, 3 cases were detected by routine physical examination, 1 by severe anemia (Hb 66g/L), 1 by gross hematuria, and 1 by flank discomfort. Before treatment, 2 cases had local metastasis (local lymph node, renal pelvis invasion), 1 had distant metastasis (pulmonary metastasis). CT examination showed that the tumors had soft tissue density / low density, with significant enhancment or uneven enhancement in enhanced scanning, and were all considered malignancy. 6 patients were all treated with surgeries, of which 5 patients received radical nephrectomy, 1 patient received nephron sparing surgery. Result Pathologically, most clear cells arranged in a papillary, nest like structure, with psaamoma bodies in them. Immunohistochemical examination showed that all patients were positive for TFE3. AE1/AE3, RCC, Vimentin, CD10, EMA, P504 were positive in different degree. According to pathological result, all 6 patients were proved to be Xp11.2 translocation renal cell carcinoma. After surgery, 2 patients received immunotherapy, 2 received targeted drug therapy, and 1 received local radiotherapy. The follow-up duration ranged from 9 to 56 months (average 37 months). Among which, 1 patient died from tumor recurrence and multiple metastasis 22 months after surgery, 1 had pulmonary metastasis 12 months after surgery, and the tumor had no significant progress after receiving targeted drug therapy. All the other patients survive without tumor recurrence. Conclusions Xp11.2 translocation renal cell carcinoma predominantly occurs in children and adults younger than 40 years. Arterial phase enhancement is slightly lower for Xp11.2 translocation renal cell carcinoma in CT scan than that of renal clear cell carcinoma. Histological features and immunohistochemical staining of TFE3 positive expression are important means of diagnosis of this disease. If necessary, gene detection could be done to make better diagnose. Surgery is preferred treatment option. Metastatic leads to poor prognosis, and need to be supplemented by targeted drug therapy. Key words: Xp11.2 translocation renal cell carcinoma; Surgery; Targeted drug therapy; Transcriptional factor E3(TFE3); Prognosis