Recurrent or symptomatic residual posterior fossa hemangioblastomas: how are they different from their primary counterparts?

BACKGROUND: Posterior fossa hemangioblastomas are WHO grade I benign lesions with a surprisingly high recurrence rate. This study determines the factors responsible for recurrence and the clinico-radiological and histopathological differences between primary (group A; n = 60) and recurrent/symptomatic residual (group B; n = 24) tumors.

METHODS: Radiologically, tumors were differentiated into cystic, cystic with a mural nodule, solid-cystic/microcystic and solid. Surgery was undertaken via a midline or lateral suboccipital approach. Histopathology differentiated them into reticular, cellular or mixed subtypes.

RESULTS: Truncal-appendicular ataxia in group A and von Hippel-Lindau (VHL) disease and raised intracranial pressure in group B were the predominant presentations. VHL patients in group B had a longer duration of symptoms (median 72 months) than those with non-VHL recurrences (median: 36 months). Multicentric mural nodules (n = 9/24, 37.50%, P = 0.0001) and bilateral cerebellar hemispheric involvement (n = 6/24, 25%, P = 0.0003) were exclusively seen in the preoperative radiology of group B tumors. Brainstem involvement was seen in the tumors of ten (16.67%) patients in group A and six (25.00%) patients in group B. One subset of patients required several resurgeries for repeated recurrences. Abnormal vascular proliferation and papillary projections into adjacent brain, and highly cellular stroma were unique histological features at recurrence. Total resection was achieved in 45 group A and 19 group B patients. The outcome based on the Karnofsky performance scale (KPS) was assessed at follow-up at 6 weeks (A: n = 60, B: n = 24): KPS0: A = 4, B = 1; KPS10-40 (dependent): A: 4, B = 5; KPS50-70 (independent for daily needs): A = 36, B = 16; KPS80-100 (fully independent): A = 16; B = 2.

CONCLUSIONS: In recurrent/residual tumors, the radiological as well as histopathological features showed a distinctive change toward a more aggressive nature. Higher incidences of multiple mural nodules, bilateral spread, remote recurrence and VHL disease at preoperative radiology; as well as proliferative angioarchitecture, an irregular brain tumor interface and highly cellular stroma at histology were found in these patients compared to their primary counterparts.