Large haemorrhage within glioblastoma mimicking haemorrhagic stroke and coexistance of meningioma: a case of collision tumours.

Intracranial collision tumours are rare pathologies in which two distinct neoplasms are found in the same location. We present an unusual case of an intracranial collision tumour composed of meningothelial meningioma (CNS WHO G1) and glioblastoma (IDH-wildtype, CNS WHO G4). This collision tumour was found in a 64-year-old man. This patient was hospitalized urgently due to left-sided hemiparesis. The computed tomography (CT) revealed large multilobar intracranial haemorrhage located in the right hemisphere. The history of hypertension and obesity pointed to the misdiagnosis of a typical haemorrhagic stroke. Despite extensive physiotherapy after initial improvement, the magnetic resonance imaging (MRI) showed signs of a marginal contrast enhancement with a suspicion of a brain tumour. Moreover, the meningioma in the same location was suspected. The neuropathological findings confirmed two neoplasms with fragments of the dura mater infiltrated by malignant glioma cells and small nests of meningothelial cells with psammoma bodies. The presented case is extremely rare showing that more malignant tumour may infiltrate a meningioma. Moreover, this case highlights the clinical observation that glioblastoma may mimic a haemorrhagic stroke. In such cases when pharmacological treatment is not effective, suspicions should be raised about a possible underlying brain tumour.