Central nervous system haemangioblastoma: a clinical and genetic study of 52 cases. Fifty two cases of haemangioblastoma were reviewed for their clinical, genetic and prognostic features. Of 34 patients with apparently isolated cerebellar lesions, postoperative outcome was good in 79%. Six isolated spinal lesions presented more insidiously and morbidity was related to incomplete resection. Twelve (23%) of the patients definitely had von Hippel-Lindau disease (VHLD). The true proportion may be higher as this diagnosis was not definitely excluded in many of the remainder; only ten patients with seemingly isolated cerebellar tumours were appropriately investigated and two had evidence of VHLD. Four out of 26 cases (15%) with apparently completely resected, isolated, cerebellar lesions later developed recurrent tumours. Brainstem and supratentorial haemangioblastomas were rare and were always associated with VHLD. The cerebellar or spinal haemangioblastomas due to VHLD had no distinctive clinical features compared with isolated tumours and there was considerable overlap in age of onset between the two groups of cases. All patients with an apparently isolated CNS haemangioblastoma should be investigated for evidence of von Hippel-Lindau disease. 