The VHL gene product (pVHL) has two macromolecular sites, α and β domains, which can bind different proteins. pVHL bound to elongin B, C/cullin/Rbx1 acts as an E3 ubiquitin ligase and targets proteins for degradation.22 Similarly, hypoxia inducible proteins are regulated by complex pVHL/elongin B and C that requires direct binding of hypoxia inducible factor (HIF) to the β domain and targets HIF for ubiquitination catalysed by the α domain.23 The VHL protein also plays a role in extracellular matrix formation and is necessary for cell cycle exit.24,25 Germline VHL mutations cause different protein defects that result in the clinical heterogeneity of VHL disease. VHL type 1 disease (without phaeochromocytoma) is associated with mutations predicted to cause complete unravelling of protein structure (missense mutations mapping to VHL protein hydrophobic core, protein truncating mutations, and partial gene deletions). VHL type 2 (with phaeochromocytoma) is caused by missense mutations which map to protein binding sites of pVHL and are predicted to cause local protein defects.22 Specific phaeochromocytoma associated missense mutations confer different risks of HAB and RCC, being responsible for the occurrence of subcategories VHL type 2A (VHL without RCC), 2B (VHL with RCC), and 2C (phaeochromocytoma only).15 Phenotypic expression of VHL disease is also influenced by genetic modifiers.26

Case presentationA 35-year-old woman with VHL underwent total pancreatectomy and right nephrectomy for pancreatic SCN and renal cell carcinoma, respectively. At the 4th year follow-up examination after the resection, contrast-enhanced computed tomography (CT) and gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) showed arterially hyper-enhanced neoplastic lesions in the segment VI and VIII of the liver. Partial resections of the liver were performed 53 months after the initial surgery. At the 6th month follow-up examination from the second surgery, one and two tumors located in the liver segment III, and VIII, respectively, were detected by contrast-enhanced CT and Gd-EOB-DTPA-enhanced MRI. Anterior segmentectomy and partial resection of the segment III were performed 66 months after the initial surgery and 13 months after the second, respectively. The tumors were pathologically diagnosed as liver metastases of pancreatic SCN synonymous with serous cystadenocarcinoma. She remains disease-free without recurrence 6.5 years after the last operation.

detected point germline vhl mutations in 14 patients