Pitfalls of conservative treatments of multiple probable cerebral cavernous malformations (CCMs): clinicopathological features of CCMs coexisting with vasculogenic mimicry in an anaplastic oligodendroglioma.

Developments in magnetic resonance imaging (MRI) techniques have dramatically increased the detection of cerebral cavernous malformations (CCMs). Conservative treatment is often recommended for asymptomatic cases. However, CCMs occasionally harbor malignant gliomas. Here, we describe a rare case of multiple probable CCMs and an anaplastic oligodendroglioma (AO) showing vasculogenic mimicry (VM) and discuss the potential pitfalls of conservative treatments. A 42-year-old otherwise healthy woman presented with generalized seizures. Magnetic resonance imaging (MRI) revealed multiple parenchymal hypointensities, particularly in the right frontal lobe, with hyperintensity on fluid-attenuated inversion recovery (FLAIR) images. The patient was diagnosed with multiple probable CCMs, and conservative treatment was administered. However, follow-up MRI showed a slightly enlarged hyperintense area in the right frontal lobe. The patient then underwent surgery; histological diagnosis was CCMs and AO with VM. The patient subsequently underwent radiotherapy and chemotherapy. No neurological deficits or tumor recurrence were evident 21 months after surgery. We present this rare case and emphasize the possibility of the coexistence of malignant gliomas with CCMs. Close observation with MRI is essential in cases of multiple probable CCMs, and a histological confirmation should be considered in cases showing any enlargement of hyperintensity on FLAIR images.