Intrinsic haematopoietic activity of cerebellar haemangioblastomas. Ultrastructural study of three cases.

Three cerebellar haemangioblastomas were studied by electron microscopy. One of these shows electron-dense granules within the tumour cells, indicative of erythropoietic activity, as previously described in a haemangioblastoma. The biological significance of these granules is discussed. Biological assay of serum erythropoietic activity was performed in one case.