Histogenesis of stromal cells in cerebellar hemangioblastomas. An immunohistochemical study

Fifteen cerebellar hemangioblastomas were examined by immunohistochemistry for expression of neuron-specific enolase (NSE) and various neuropeptides using the avidin-biotin-complex peroxidase reaction with the following antibodies: NSE, synaptophysin, serotonin, substance P, vasoactive intestinal peptide (VIP), neuropeptide YY, neurotensin, and leu-enkephalin. In all tumor biopsies most of the stromal cells were positive for NSE. About 30% of the stromal cells showed a weak cytoplasmic synaptophysin positivity. Approximately 25% of the stromal cells were labeled with antibodies against substance P and neuropeptide YY. The partly strong reactivity was localized preferentially in perinuclear regions. These positive cells were mainly distributed in small cell clusters but were also scattered in the tumor parenchyma. In all tumor biopsies scattered cells exhibited strong perinuclear enkephalin positivity, corresponding probably to mast cells, whereas stromal cells were entirely negative. For serotonin, VIP, and neurotensin no specific reaction was seen. On the basis of these findings it is proposed that hemangioblastomas have a neuroendocrine component.