MiT Family Translocation Renal Cell Carcinoma ─ A Case Report
Tzu-Shuang Chen1, Yun-Ping Chen2, Yen-Ta Chen1
Department of Urology1 and Pathology2, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
Introduction: The new category of MiT family translocation renal cell carcinoma(TRCC) has been included into the World Health Organization classification in 2016. The TRCC includes Xp11 translocation renal cell carcinoma with TFE3 gene fusions and t(6;11) renal cell carcinoma with TFEB gene fusion. The prognosis of this tumor is poorer compared with other subtypes of RCC and is mostly diagnosed at an advanced stage. However, a standardized therapy for TRCC has not yet been established. We here present a case of Xp11 translocation RCC controlled with pazopanib therapy and radical nephrectomy.
Case presentation: A 50-year old man suffered from right flank pain and intermittent gross hematuria for 2 months. The laboratory tests revealed mild normocytic anemia, chronic kidney disease stage 3 and high levels of lactate dehydrogenase. Computerized tomography revealed a infiltrative heterogeneously enhancing tumor nearly occupied the whole right kidney (10.7x8.6cm) and invaded right renal vein with thrombus and increase thickness of wall of right upper ureter. Multiple prominent lymph nodes over paracaval, precaval and retrocaval and mesentery regions were also identified. The patient was diagnosed with RCC of clinical stage T3aN1M0. The patient underwent a ultrasound guided percutaneous core needle biopsy of the renal tumor. In the immunohistochemical (IHC) study, the tumor cells are diffuse positive for TFE3 stain. In addition, the tumor cells are positive for PAX8 stain, and negative for Cathepsin-k, CK7, CAIX and CD117. Thus, the pathological diagnosis was Xp11 translocation RCC. Pazopanib treatment was administered for 3 months initially. After target therapy, the patient received right radical nephrectomy and repair of inferior vena cava. At 2 months after surgery, follow-up computed tomography revealed there was no recurrent tumor noted.
Discussion: We herein present a case of Xp11 translocation RCC that was treated with Pazopanib and status post radical nephrectomy followed for 2 months after surgery. With regard to the treatment, the optimal therapy for TRCC remains to be determined. To date, there is no data regarding predictive markers to choose the best therapy for an individual patient. It is necessary to identify these cases in future clinical trials and search for effective therapies.