Differentiation of clear cell ependymoma of the cerebellum from hemangioblastoma by Thallium-201 single photon emission computed tomography - Case report

A 57-year-old man suffered from dizziness for about one year and truncal ataxia for about one month. Magnetic resonance imaging demonstrated a cystic tumor with a homogeneously enhanced mural nodule located in the cerebellar vermis. Computed tomography angiography revealed a hypervascular nodule. These findings were compatible with hemangioblastoma. Thallium-201 single photon emission computed tomography (²⁰¹Tl-SPECT) showed moderately high uptake in the early phase and moderately high retention in the delayed phase, whereas hemangioblastoma shows almost no retention in the delayed phase. The patient underwent total removal of the tumor. The histological diagnosis was clear cell ependymoma (CCE). CCE is a rare subtype of ependymoma, which resembles hemangioblastoma in histological and neuroimaging findings, but is considerably more aggressive. ²⁰¹Tl-SPECT can provide useful information for the preoperative differential diagnosis of infratentorial CCE and hemangioblastoma.