Intracranial primary collision tumours: A comprehensive systematic review on preoperative radiological accuracy and...

Intracranial collision tumours, characterized by the coexistence of two histologically distinct neoplasms within the same anatomical region without histological transition or metastatic interaction, are rare in neuro-oncology. Their atypical imaging appearance often mimics solitary lesions, posing diagnostic challenges.

How accurately can preoperative neuroimaging identify both components of intracranial collision tumours, and what factors influence detection?

A systematic review was conducted following PRISMA guidelines and registered with PROSPERO (CRD420251008646). Included studies were adult case reports and series, including histologically confirmed intracranial collision lesions with preoperative neuroimaging. Tumour-to-tumour metastasis, synchronous, composite, or recurrent tumours were excluded.

A total of 67 published cases were analysed, with a male-to-female ratio of 28:38 and a mean age of 52.4 years (SD = 15.95), ranging from 18 to 87 years. Meningioma was the most prevalent tumour type (65.7 %), commonly paired with glioblastoma (26.9 %). The sellar region was the most frequent location (34.3 %), followed by the two frontal lobes (31.3 %). Preoperative diagnosis correctly identified both lesions in only 26.9 % of cases. Detection rates varied by anatomical location (p = 0.0095), whereas no clear association was observed with tumour pair type (p = 0.1351). Surgical resection was the primary treatment, frequently combined with chemo-radiotherapy. Recurrence occurred in 17.9 %, especially in high-grade tumour components such as glioblastoma. Mean survival was 8.6 months, with 11.9 % mortality. No statistically significant survival differences were observed between tumour pair types (p = 0.149).

Intracranial collision tumours remain diagnostically challenging. Improved neuroimaging and molecular understanding are crucial to enhance early diagnosis and optimize clinical management.