Foci of extramedullary haemopoiesis in a cerebellar haemangioblastoma.

A posterior fossa haemangioblastoma is described which contained foci of extramedullary haemopoiesis. Although secondary polycythemia has been reported with a frequency of between 5 and 30% in patients with haemangioblastomas only five cases have been described previously in the English literature where haemopoietic tissue was identified in the tumour.