Xp11 / TFE3 Translocation Carcinoma of the Kidney

Definition

Renal carcinoma comprising a large fraction of renal carcinomas occurring in young patients and associated with translocations involving the TFE3 gene at chromosome Xp11.2

Most cases reported in children and young adults, mean age 25 years
- Under-recognized in adults
  - Two studies find an incidence of 1-5% in adults (Zhong, Sukov)
  - If possible, fresh tumor tissue should be sent for cytogenetics in all renal tumor patients under 40 years of age and in older patients in which an unusual tumor is discovered at frozen section
Composed of cells with abundant to voluminous cytoplasm
- Clear to granular eosinophilic cytoplasm
- Sharp cell borders
Pleomorphic and polymorphic growth patterns

Clusters of small cells centered on hyaline cores may be seen
- Collections of small cells should suggest a t(6;11) carcinoma
Patterns and cells may vary according to the precise translocation involved

Large vesicular nuclei
- Prominent round nucleoli
- Mitotic figures frequent
Features frequently present
- Psammoma bodies may be abundant
- Intracytoplasmic hyaline droplets
Melanocytic variant has been reported
Presence of Xp11 translocation by classical cytogenetics, PCR or FISH
- Demonstration may not be required in every case
- TFE3 immunohistochemistry may be less reliable than reported in the literature with numerous false positives
- Lack of, or minimal, cytokeratin and EMA expression may be the most helpful immunophenotypic findings

John P Higgins MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342