Melanotic Translocation Renal Cell Carcinoma With a Novel ARID1B-TFE3 Gene Fusion

Am J Surg Pathol. 2017 Nov;41(11):1576-1580. doi: 10.1097/PAS.0000000000000927.

Abstract

A 36-year-old male was found to have a 7.0 cm left upper pole renal mass on renal ultrasound. Following nephrectomy, the mass was grossly ill-demarcated, friable and red-brown, invading renal parenchyma, hilar fat and the renal vein. Microscopically, the tumor had a nested and papillary architecture. The cells demonstrated abundant clear and eosinophilic cytoplasm and focal intracytoplasmic melanin pigment. Nucleoli were prominent. By immunohistochemistry, the tumor was positive for TFE3; HMB-45 stained approximately 5% of tumor cells corresponding to the histologic melanin pigment, which was confirmed with Fontana-Masson stain with bleach. Immunostains for PAX8, CD10, MiTF, and CAIX were negative; keratins Cam 5.2 and AE1/AE3 were focally positive. Targeted next-generation sequencing revealed an ARID1B-TFE3 gene fusion. Melanotic Xp11 renal cell carcinoma is a rare, pigment containing translocation variant demonstrating overlapping features with melanoma and is usually associated with an SFPQ-TFE3 gene fusion. The patient is alive and without evidence of disease 7 years after his diagnosis. The combination of high grade histopathology, the presence of melanin, absent PAX8, keratin positivity, and relatively indolent clinical behavior with a unique translocation may warrant recognition as a distinct renal cell carcinoma translocation subtype.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / analysis
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / genetics*
  • Biomarkers, Tumor* / analysis
  • Biomarkers, Tumor* / genetics
  • Biopsy
  • Carcinoma, Renal Cell / chemistry
  • Carcinoma, Renal Cell / genetics*
  • Carcinoma, Renal Cell / pathology
  • Carcinoma, Renal Cell / surgery
  • Chromosomes, Human, X*
  • DNA-Binding Proteins / genetics*
  • Gene Fusion*
  • Genetic Predisposition to Disease
  • Humans
  • Immunohistochemistry
  • Keratins / analysis
  • Kidney Neoplasms / chemistry
  • Kidney Neoplasms / genetics*
  • Kidney Neoplasms / pathology
  • Kidney Neoplasms / surgery
  • Male
  • Melanins / analysis*
  • Neoplasm Grading
  • Nephrectomy
  • PAX8 Transcription Factor / analysis
  • Phenotype
  • Sequence Analysis, DNA
  • Transcription Factors / genetics*
  • Translocation, Genetic*

Substances

  • ARID1B protein, human
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • Biomarkers, Tumor
  • DNA-Binding Proteins
  • Melanins
  • PAX8 Transcription Factor
  • PAX8 protein, human
  • TFE3 protein, human
  • Transcription Factors
  • Keratins