Intradural, extramedullary hemangioblastoma at the level of the conus medullaris: illustrative case

Abstract

Background: Hemangioblastomas are rare, slow-growing, and highly vascularized tumors that typically occur in the cerebellum and spinal cord. The cervical and thoracic regions are the most common spinal sites, and the tumors are usually intramedullary.

Observations: The authors report the case of a man whose chest computed tomography performed for managing coronavirus disease 2019 incidentally revealed an enhancing area in the spinal canal at T12-L1. The patient reported low back pain as well as leg numbness and tingling. Magnetic resonance imaging of the lumbar region with and without gadolinium contrast demonstrated an intradural, extramedullary lesion with displacement of the conus medullaris. The differential diagnosis included a schwannoma and myxopapillary ependymoma. Bilateral T12-L1 laminectomies were performed with resection of the mass. The general pathologist rendered the frozen section diagnosis of a spindle cell neoplasm, suggesting the differential diagnosis of schwannoma or myxopapillary ependymoma. Immunohistochemistry was positive for inhibin, GFAP, reticulin, CD31, SOX-10, S100, and EMA. A World Health Organization grade 1 hemangioblastoma was confirmed.

Lessons: Spinal surgeons should be cognizant of the presenting symptoms and differential diagnosis of hemangioblastomas at the level of the conus medullaris, especially when the tumor is diagnosed incidentally. Additional investigations should be performed to determine whether von Hippel-Lindau syndrome is associated with the hemangioblastoma, as this combination portends a different clinical presentation, multiple tumor locations, and tumor recurrence following resection.

Keywords: CNS = central nervous system; CT = computed tomography; MRI = magnetic resonance imaging; conus medullaris; extramedullary; hemangioblastoma; intradural; neurosurgery.

FIG. 1.

Sagittal (A) and axial (B) MRI (T2) scans demonstrating an intradural, extramedullary mass at T12–L1 (arrows). High flow void vascular abnormalities can be seen within the tumor. Sagittal (C) and axial (D) gadolinium-enhanced T1-weighted fat-saturation MRI scans reveal the intradural, extramedullary mass displacing the conus medullaris from left to right (arrows).

FIG. 2.

Surgical photograph demonstrating the hemangioblastoma (arrowheads) severely displacing the nerves of the cauda equina (asterisks).

FIG. 3.

A: Hematoxylin and eosin (H&E) stain, original magnification ×100. B: H&E stain, original magnification ×400. C: Inhibin immunohistochemistry, original magnification ×200. D: Ki-67 immunohistochemistry, original magnification ×100.