N63 Natural history of renal tumors in von Hippel-Lindau syndrome

The von Hippel-Lindau (VHL) disease is a hereditary cancer predisposition syndrome with autosomal dominant pattern of inheritance, with high penetrance but variable expression, dependent mostly on age. Its prevalence is 1:39 000–1:53 000. The VHL gene, localized to chromosome 3p25–26 belongs to suppressor genes and was identified in 1993. Affected individuals have a risk of cancer and tumor-like lesions, including retinal angiomas, hemangioblastomas of the central nervous system, renal cysts, renal cell carcinomas (RCC), pheochromocytoma, epididymal cysts and cystadenomas, liver and pancreatic cysts. Morphologically renal lesions vary from simple cysts, through hyperplastic cysts with multiple cell layers and cysts containing clear cell carcinoma, to solid renal lesions. Cysts are usually multiple, bilateral in 30%, mostly asymptomatic. They precede solid lesions about 3–7 years. Solid lesions are always RCC. In 10% RCC is a first diagnosed lesion of VHL. Cumulated risk of RCC in 6^th decade is ∼70%. RCC is a leading cause of death in VHL patients [1–3]. Clinical features of RCC in VHL syndrome comprise multifocality, bilateral lesions, usually with dense fibrotic capsule, rare metastases especially if primary tumor smaller than 3–7 cm, lower grading, and longer 10 years survival comparing with sporadic RCC. It occurs about 20 years earlier than sporadic RCC. Mean rate of growth for solid renal lesions according to a few papers oscillates from 0.26 cm/year (range 0–1.2) [1], through 0.54 (0.26–0.9) [3] to 1.6 (0.2–2.2) [2].

Retrospective analysis of radiological documentation of the biggest solid lesions of 5 patients with VHL was done. Mean value of the rate of tumor growth for individual patient and mean value for all the group were counted.

The rate of tumor growth for individual patient shows table 1.

All observed renal solid lesions increased with time. The rate of tumor growth in our study is similar to results from the literature. Big differences of studied value necessitate individualized therapeutic approach to each patient.