Radiation-induced cerebral cavernous malformations.

PURPOSE: Cerebral cavernous malformations (CCMs) are hamartomatous vascular lesions. A part of CCMs is estimated to occur after cranial irradiation. However, there have been no reports documenting clinical picture of such CCMs. This study aimed to explore it.

METHODS

A total of 51 patients with multiple CCMs who visited our hospital, between 2006 and 2024, were explored. Among them, five were considered to have radiation-induced CCMs, four developing after cranial irradiation and one after endovascular therapy.

RESULTS

The male-to-female ratio of radiation-induced CCM cases was 3:2. The mean time from radiation exposure to identification of CCM mutation was 31.2 years. Four patients developed symptomatic meningioma and underwent surgical resection. In all cases, the pathological diagnosis was meningothelial meningioma. Genomic analysis of CCMs confirmed a CCM1 mutation in five patients. In four cases, the mutation was located in exon 5. In contrast, it was found in only one of the 46 patients with CCM who did not have previous radiation exposure.

CONCLUSIONS

Radiation-induced CCMs may occur through a mechanism different from common hereditary CCMs, showing a stable clinical course, and incidentally found with symptomatic secondary tumors. Exon 5 of chromosome 7 may be more sensitive to radiation than other genomic loci.