Intracanalicular vestibular schwannoma--therapeutic options.

The growth of purely intrameatal vestibular schwannoma (VS) was investigated in a series of 40 patients with 40 unilateral VS in the period 1973 to 1996 (mean 3.6 years). Twenty-seven tumours (67.5%) revealed growth and 13 tumours (32%) had no measurable growth. Four growth patterns were observed: (i) 15 tumours (37.5%) exhibited constant growth; (ii) 13 tumours (32.5%) had no measurable growth; (iii) 8 tumours (20%) revealed growth subsequent to a no-growth period; and (iv) 4 tumours (10%) manifested different growth patterns during the observation period. The mean diameter growth per year was 3.2 mm. The findings of the present study, especially those achieved in groups B (the non-growing tumours) and C (tumour growth subsequent to a silent period), question the reliability of the results achieved by radiosurgery, as no tumour growth may occur with no intervention.