Abstract
Background: Hemangioblastoma is an indolent mesenchymal tumor most frequently occurring in the central nervous system (CNS), but can also arise extraneuraxially, as part of von Hippel-Lindau (VHL) disease or in sporadic cases. Extraneuraxial hemangioblastomas (EH) occur outside the central nervous system. It includes tumors arising from the nervous paraneuraxial structures and visceral organs. Sporadic hemangioblastoma of the kidney, a rare subset of EH, is an under-recognized renal neoplasm. There have been only 25 cases described to date in the English language literature. We report herein one additional case in a patient without VHL disease.Case presentation: A 61 year old male presenting with gross hematuria was found to have a 3.5 cm renal mass at the lateral mid to lower pole of the left kidney on computed tomography urogram. Patient underwent a partial nephrectomy for the mass. The pathological examination showed a well-circumscribed non-encapsulated tumor composed of sheets of large polygonal cells traversed by a rich vascular network. The tumor cells showed clear to eosinophilic cytoplasm and overall bland nuclei. The diagnosis of hemangioblastoma was confirmed by positive immunostaining for alpha-inhibin, S100, neuron-specific enolase, PAX8, and negative staining for epithelial membrane antigen, HMB-45, and Melan-A. VHL gene mutation was not detected in this tumor. The diagnosis of sporadic renal hemangioblastoma was made.Conclusion: Sporadic renal hemangioblastoma (RH) is a rare subset of EH. We report herein one such case in a patient without clinical or molecular evidence of VHL disease. We reviewed the literature to better understand the clinical, radiological and pathologic features of this neoplasm. From our review cases and the present case, we have found that the majority of RHs showed a positive immunostaining for PAX8, which supports the idea that the immunoprofiles of EH can vary depending on sites of origin. Diagnosis of renal hemangioblastoma is challenging because of its rarity and overlapping microscopic and immunophenotypic features with renal cell tumor, especially with clear cell renal cell carcinoma. However, accurate diagnosis is necessary, since RH is clinically benign and correct recognition of this pathological entity is important to avoid unnecessary over treatment.
Pathology of the Nervous System in Von Hippel-Lindau Disease