XP11.2 translocation renal cell carcinoma: clinical experience of Taipei Veterans General Hospital

Abstract

Background: Xp11.2 translocation renal cell carcinoma (RCC), a recently recognized distinct subtype of RCC, is characterized by various translocations, all involving the TFE3 transcription factor gene. These rare cancers occur predominantly in children and young adults and comprise about one-third of pediatric RCCs. In the present study, we review the clinical course of Xp11.2 translocation renal cell carcinoma in our institution.

Methods: We identified eight cases with Xp11.2 translocation RCC between 2007 and 2010 from the pathological archives of the Taipei Veterans General Hospital. We retrospectively analyzed the patients' characteristics, clinical manifestations, and specific pathological features for definitive diagnosis, surgical and systemic treatment and clinical outcome of these rare cancers.

Results: Patients were aged 20 years to 49 years (mean age 28 years) with female predominance (6 females, 2 males). One patient presented with asymptomatic renal mass detected incidentally during abdominal sonography. Four patients complained of flank or abdominal pain, and the other three complained of gross hematuria at initial presentation. The mean tumor size was 9.2 cm (range, 4 cm-17 cm). Seven patients underwent radical nephrectomy for the primary tumor, while one presented with multiple metastases. All cases were confirmed by TFE3 immunohistochemistry, a sensitive and specific marker of tumors with TFE3 gene fusion, which showed positive nuclear staining. Three patients presented initially with metastatic diseases, and another three patients progressed to lung, liver and bone metastases at eight, seven and nine months postoperatively.

Conclusion: Although RT-PCR and DNA sequencing are the final diagnoses of the molecular identity of Xp11.2 translocation RCC, experienced pathologists could confirm the histologic diagnosis based on the distinctive morphologic features with positive TFE3 immunochemical nuclear stain. Surgical resection is the only treatment. The role of systemic therapy for local recurrence and metastasis remains to be determined.