Surgical management and long-term outcome of intracranial subependymoma

Background: Intracranial subependymomas account for 0.2-0.7% of central nervous system tumours and are classified as World Health Organization (WHO) grade 1 tumours. They are typically located within the ventricular system and are detected incidentally or with symptoms of hydrocephalus. Due to paucity of studies exploring this tumour type, the objective was to determine the medium- to long-term outcome of intracranial subependymoma treated by surgical resection.

Methods: Retrospective case note review of adults with intracranial WHO grade 1 subependymoma diagnosed between 1990 and 2015 at the Walton Centre NHS Foundation Trust was undertaken. Tumour location, extent of resection (defined as gross total resection (GTR), sub-total resection (STR) or biopsy) and the WHO performance status at presentation and through follow-up were recorded.

Results: Thirteen patients (7 males; 6 females) with a mean age of 47.6 years (range 33-58 years) and a median follow-up of 46 months (range 25-220 months) were studied. Eight patients had symptomatic tumours (headache, visual disturbance); five had incidental finding. Tumours were most commonly located in the fourth ventricle (n = 8). The performance status scores at diagnosis were 0 (n = 8) and 1 (n = 5). The early post-operative performance status scores at 6 months were 0 (n = 5) and 1 (n = 8) and at last follow-up were 0 (n = 11) and 1 (n = 2). There was no evidence of tumour re-growth following GTR or STR. The commonest complication was hydrocephalus (n = 3).

Conclusion: Subependymoma are indolent tumours. No patients exhibited a worsening of performance status at medium- to long-term follow-up and there were no tumour recurrence suggesting a shorter follow-up time may be sufficient. Surgical resection is indicated for symptomatic tumours or those without a clear imaging diagnosis. Incidental intraventricular subependymoma can be managed conservatively through MRI surveillance.