Clinical and radiological presentation of cavernomas according to the Zabramski classification

Cerebral cavernous malformations (CCMs) are a cluster of abnormal vessels of the brain. CCMs have a low risk for intracerebral hemorrhage and appear increasingly often as incidental findings on MRI. Zabramski classification has been used to describe the radiological features of CCMs. How the Zabramski classification associates with the clinical symptoms at presentation and clinical course of the disease is not well established.

The authors reviewed the medical records of conservatively managed and surgically treated CCM patients over a 20-year period treated in Kuopio and Tampere University Hospitals. Both clinical and radiological data were analyzed. The modified Rankin Scale (mRS) was used to score the symptoms.

Altogether, 775 CCM patients were identified. In both cohorts, most patients were asymptomatic (53% in the Kuopio University Hospital [KUH] cohort and 64% in the Tampere University Hospital [TAUH] cohort). Most CCMs were located supratentorially (77%, 661/858), and most patients presented with epileptic seizures. Of the infratentorial CCMs, most were located in the cerebellum (61%, 121/198). The most common symptoms caused by these CCMs were double vision, sensory deficits, and impaired balance. The median mRS score for symptoms in all CCMs was 0, and if only symptomatic CCMs were accounted for, it was 2. Most CCMs were Zabramski type II, and these CCMs were relatively asymptomatic, similar to Zabramski type III CCMs. Zabramski type I CCMs were mostly symptomatic, whereas Zabramski type IV CCMs were completely asymptomatic. Of patients with type I CCMs, approximately 15% developed new symptoms within 1 year, and in the long-term follow-up 26% had new symptoms. In radiological follow-up, 81% of the type I CCMs regressed to type II or III. Of type II or III CCMs, 2.3% changed over time to type I. Age was associated with the Zabramski classification (p < 0.001 in the TAUH cohort and p = 0.034 in the KUH cohort).

Most CCMs are asymptomatic, incidental findings, in particular, nearly all Zabramski type IV CCMs. If symptoms are present, they are mainly associated with Zabramski type I CCMs and occasionally with Zabramski type II or III CCMs. Although most Zabramski type I CCMs will regress to type II or III and remain asymptomatic, over long-term follow-up, up to one-quarter develop new symptoms.