Recurrent Tuberous Sclerosis Complex/Mammalian Target of Rapamycin Mutations Define Primary Renal Hemangioblastoma as a Unique Entity Distinct From Its Central Nervous System Counterpart

Am J Surg Pathol. 2024 Jul 1;48(7):874-882. doi: 10.1097/PAS.0000000000002211. Epub 2024 Mar 19.

Abstract

Renal hemangioblastoma (HB) is a rare subset of HBs arising outside of the central nervous system (CNS), with its molecular drivers remaining entirely unknown. There were no significant alterations detected in previous studies, including von Hippel-Lindau gene alterations, which are commonly associated with CNS-HB. This study aimed to determine the real molecular identity of renal HB and better understand its relationship with CNS-HB. A cohort of 10 renal HBs was submitted for next-generation sequencing technology. As a control, 5 classic CNS-HBs were similarly analyzed. Based on the molecular results, glycoprotein nonmetastatic B (GPNMB) immunohistochemistry was further performed in the cases of renal HB and CNS-HB. Mutational analysis demonstrated that all 10 renal HBs harbored somatic mutations in tuberous sclerosis complex 1 ( TSC1 , 5 cases), TSC2 (3 cases), and mammalian target of rapamycin (2 cases), with the majority classified as pathogenic or likely pathogenic. The CNS-HB cohort uniformly demonstrated somatic mutations in the von Hippel-Lindau gene. GPNMB was strong and diffuse in all 10 renal HBs and completely negative in CNS-HBs, reinforcing the molecular findings. Our study reveals a specific molecular hallmark in renal HB, characterized by recurrent TSC/mammalian target of rapamycin mutations, which defines it as a unique entity distinct from CNS-HB. This molecular finding potentially expands the therapeutic options for patients with renal HB. GPNMB can be considered for inclusion in immunohistochemical panels to improve renal HB identification.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Biomarkers, Tumor / analysis
  • Biomarkers, Tumor / genetics
  • Central Nervous System Neoplasms / chemistry
  • Central Nervous System Neoplasms / genetics
  • Central Nervous System Neoplasms / pathology
  • Child
  • DNA Mutational Analysis
  • Female
  • Genetic Predisposition to Disease
  • Hemangioblastoma* / chemistry
  • Hemangioblastoma* / genetics
  • Hemangioblastoma* / pathology
  • High-Throughput Nucleotide Sequencing
  • Humans
  • Immunohistochemistry
  • Kidney Neoplasms* / chemistry
  • Kidney Neoplasms* / genetics
  • Kidney Neoplasms* / pathology
  • Male
  • Middle Aged
  • Mutation*
  • Phenotype
  • TOR Serine-Threonine Kinases* / genetics
  • TOR Serine-Threonine Kinases* / metabolism
  • Tuberous Sclerosis / genetics
  • Tuberous Sclerosis / pathology
  • Tuberous Sclerosis Complex 1 Protein / genetics
  • Tuberous Sclerosis Complex 2 Protein* / genetics
  • Young Adult

Substances

  • Tuberous Sclerosis Complex 2 Protein
  • MTOR protein, human
  • TOR Serine-Threonine Kinases
  • TSC2 protein, human
  • Biomarkers, Tumor
  • Tuberous Sclerosis Complex 1 Protein
  • TSC1 protein, human