Cerebellopontine angle epidermoid cysts. Experience of 43 cases with long-term follow-up.

BACKGROUND

Epidermoid tumors represent the third most common lesion of the cerebellopontine angle (CPA). Their evolution and clinical features are distinctively characteristic. We present a comprehensive review of the clinical, imaging and surgical aspects of epidermoid cysts of the CPA.

METHODS

We conducted a case series of patients diagnosed with epidermoid cyst of the CPA who were operated on between 1998 and 2005. Lesions were classified according to their anatomic extent: grade I(-) within the boundaries of the CPA, grade II(-) extension to the suprasellar and perimesencephalic cisterns, and grade III(-) parasellar and temporomesial region involvement.

RESULTS

This study was comprised of 43 patients with a mean follow-up of 85 months. Mean age was 34 years, and 67% of the patients were female. The initial symptom was headache in 58.1% of the cases and trigeminal neuralgia in 41.8%. According to our classification, temporomesial involvement (25.6%) was significantly (p = 0.001) associated with a higher incidence of seizures, and trigeminal neuralgia was present in patients with lesions limited to the CPA (p = 0.006). The lesions were reached essentially through a retrosigmoidal approach (39.5%) and surgical excision was deemed to be complete in 65% of the cases.

CONCLUSIONS

Our grading classification according to the anatomic extension correlates well with clinical presentation, type of surgical approach and extent of surgical removal. It is desirable to reach a consensus on the classification of tumor extension.