Teaching Case

A 22-year-old male presented with a holocranial headache for three months. Two days ago, the patient manifested a recent worsening of the symptoms. The patient also referred to an episode of retrograde amnesia one day ago. Imaging studies were performed.

Computed tomography (CT)  showed a heterogeneous solid and cystic expansile lesion, with a slightly hyperdense solid nodule (Fig. 1a). There was intense contrast enhancement of the solid portion with non-enhancing areas indicating small cystic components (Fig. 1b, Fig. 1c). The lesion had mass effect and diverted the cerebral falx contralaterally (Fig. 1a, Fig. 1c).

Magnetic resonance imaging (MRI) showed an expansive lesion with intra- and peritumoral cystic components (Fig. 2). There were T1-hypersignal foci suggestive of methaemoglobin within the solid component (Fig. 2a). T2 and SWI showed hypointense areas suggestive of blood degradation components (Fig. 2c, Fig. 3a).

DWI did not demonstrate facilitated diffusion (Fig. 3b), with ADC estimated in 0.7 x 10-3 mm² / s (Fig. 3c). Perfusion depicted significant areas of increased rCBV within the tumour (Fig. 4).

Hemangioblastoma is a grade I vascular tumour of the WHO classification [1]. It represents up to 2.5% of the central nervous system's tumours, with approximately 95% located in the posterior fossa [1,2]. Only 5% is in the supratentorial compartment [2]. Most lesions present with facilitated diffusion and a significant perfusion increase due to the high vascular density [3].

The most typical presentation is a posterior fossa solid-cystic tumour in an adult aged 30-65 years, presenting a solid component with intense contrast enhancement, high CBV and facilitated diffusion [1,4].

Hemangioblastomas can be sporadic or associated with von-Hippel-Lindau phakomatosis. In cases of supratentorial hemangioblastomas, this association is even more frequent [1,2,5]. In the case presented, there were no other findings related to the syndrome.

Besides, supratentorial hemangioblastomas also show a higher growth rate and fewer cysts' formation than their infratentorial counterparts [2]. Above the cerebellar tentorium, the most frequent locations include the optical pathways, frontal lobe, parietal, intraventricular, and meninges [2].

The solid-cystic aspect, the presence of flow voids, and high perfusion should raise the possibility of a hemangioblastoma in an adult. Post-surgery histopathologic analysis corroborated the diagnosis in this case. The radiologists must be alert to the diagnosis of hemangioblastoma even in an atypical (supratentorial) location. In addition, the absence of facilitated diffusion does not exclude the diagnosis.