Sporadic Renal Hemangioblastoma: A Case Report of a Rare Entity.

Hemangioblastoma, also known as capillary hemangioblastoma, is a rare benign mesenchymal tumor commonly found in the central nervous system (CNS). It can also manifest in various organs, including the kidney. Renal hemangioblastoma (RH) is often associated with Von Hippel-Lindau (VHL) disease, but sporadic occurrences are observed infrequently. While RH is usually asymptomatic, it can also cause abdominal pain and hematuria. In this study, we present a case of an elderly patient without history of VHL but complaining of abdominal pain for three days. Serological evaluations were unremarkable, and a CT scan identified a 2.4 cm mixed solid-cystic mass lesion on the left kidney's superior aspect. The patient subsequently underwent a biopsy followed by lesion ablation. Microscopic analysis revealed sheets of eosinophilic cells with ovoid nuclei, showing focal rhabdoid and spindle cell features, with an intricate capillary network. Focal nuclear atypia without necrosis or mitosis was noted. Immunohistochemistry (IHC) demonstrated positive staining for inhibin, S100, PAX8, and vimentin, along with patchy positivity for CD10 and RCC. Negative staining was observed for cytokeratin AE1/AE3, CK7, EMA, CK8/18, desmin, and HMB-45. The overall morphological characteristics and distinct IHC markers were consistent with RH. Although its pathogenesis remains unclear because of its rarity, distinguishing RH from renal cell carcinoma is crucial. IHC markers facilitate differentiation among lesions. The preferred treatment involves ablation or partial nephrectomy. Further assessment for possible VHL syndrome is essential, considering the distinct management approaches for sporadic and VHL-linked RH.