A rare case of peripheral nerve hemangioblastoma—case report and literature review.

Hemangioblastoma is a rare benign tumor that consists of neoplastic vacuolated stromal cells and highly developed capillary blood vessels. These tumors are almost exclusively found in the central nervous system, but in extremely rare cases, it can arise in peripheral nerves. In the majority of cases, it occurs sporadically (60 to 75%), but in about 25% of cases, it is associated with von Hippel-Lindau disease. We present the first case of ulnar nerve hemangioblastoma in a 70-year-old male. The patient presented with a slow-growing palpable mass on the front side of the right upper arm. Macroscopically, the tumor was round shaped, encapsulated, reddish-orange in color, very well vascularized, and about 3 cm in diameter; one nerve fascicle was entering the tumor tissue, so it was resected with the tumor. The rest of the nerve fascicles were intact. Postoperative course was uneventful. Histopathological analysis with immunohistochemical analysis confirmed that the tumor was a peripheral nerve hemangioblastoma WHO grade I. Physical treatment was conducted, and there was no motor neurological deficit on follow-up after 3 months, only hypoesthesia of the fourth and fifth finger. These lesions are so rarely found arising from peripheral nerves that only four published cases exist in literature today. There is very little data about these tumors in world literature, so we consider our paper a valuable contribution to global knowledge on these tumors.