A Rare Renal Cell Carcinoma Associated With Xp11.2 Translocation/TFE3 Gene Fusion

Background: XP 11.2 translocation TFE3 gene fusion renal cell carcinoma(RCC)is enlisted as a rare subtype of renal cell carcinoma by World Health Organization(WHO)in 2004.This type of tumor was previously considered as a pediatric tumor predominantly,but now invariably found in adult and older patients.In the advanced stage,the incidence of organ metastasis is very high,and the prognosis is relatively poor.The study found that compared to the children,adult patients with more advanced stages have relatively poorer prognoses.Objective: The article aims to find out and investigate the clinical manifestation,pathological features,diagnosis,and treatment of this rare subtype XP11.2/TFE3 gene fusion RCC and give a review of the literature.Methods: We collect the clinical data and general information 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.We analyzed the data respectively and the literature related to XP11.2/TFE3 RCC was reviewed.Results: In the present research,there was a total of eight patients who were confirmedly diagnosed with XP11.2 TFE3 gene fusion RCC from August 2015 to November 2018.Among them,there were 3 male patients and 5 female patients,with the average age of 33.25 years old,ranging from 5 years old to 62 years old.6 patients were asymptomatic and diagnosed primarily incidentally.And one of them was complaining of hematuria and back pain for 3 months and another patient complained just back pain for 4 months.After hospital admission,transabdominal ultrasonography,CT scan,and MRI imaging were done to all the patients.The tumor sizes of 2 patients were more than 7cm;3 patients were 5-6 cm,and rest 3 patients were below 4cm.Only 1 patient performed Right Open Radical Nephrectomy and Right Ureterectomy.Radical nephrectomy was done in 4 patients and partial nephrectomies were done in the rest 3 patients.All patient’s tumor samples were sent for pathology and immunohistochemistry.All were positive for CD10,TFE3,and RCC.Other parameters varied from each other.One postoperative patient got both chemotherapy and targeted therapy,3 patients were treated with interferon but changed to thymopentin because of adverse effects.Only 1patient got thymopentin and the rest 3 patients didn’t need any adjuvant therapy.Follow up was done to all patients from 6 months to 40 months.Except for one patient who died at 16 months of surgery due to lung metastasis,all patients were found normal without any further progress of the disease.Conclusion: The clinical features and sign symptoms of XP11.2 TFE3 gene fusion RCC were similar to other renal cell tumors.There may some differences in imaging,though it always varies among different patients with various tumor morphologies.So far,the golden standard of diagnosis is the postoperative pathology and immune histochemistry.Radical or partial nephrectomy combining with renal lymph node clearance should be performed if there is metastasis of lymph nodes.Proper adjuvant therapy including chemotherapies,targeted therapy,and immune therapy should be applied when needed.Immunotherapy found more beneficial in this regard.Follow up must be done every 6 months or yearly at least with a physical examination,laboratory examination,and imaging to maintain a risk-free life.