Mononuclear cell infiltrate, HLA-Dr expression and proliferation in 37 acoustic schwannomas

Frozen sections from 37 schwannomas of the V111 nerve were reacted with a panel of monoclonal antibodies to macrophage, lymphocyte, I-ILA-Dr invariant chain and nuclear proliferation antigens. A moderate number of rnacrophages was demonstrated in 96% of tumours. CD8- and CD4- lymphocytes were detected in slightly smaller numbers in up to 87% and 23% of tumours respectively. B-lyrnphocytes were present in only 2/32 cases and NK-cells were absent from all 16 cases tested. HLA-Dr antigen was expressed by macrophages in most cases and by tumour cells in 13/24 tumours. These findings may represent evidence for a degree of cellular immune response. Occasional cells featuring nuclear proliferation were detected in 15/27 cases

lmmunohistological signposts in central nervous system tumours with neuronal differentiation

25 neuronal tumours with a panel of antibodies were studied and it was found that vimentin was present in 15 tumours. It was also found in a few cells within rosettes. PGP 9.5 showed a somatic pattern of staining with nuclear and perinuclear positivity in 23. Neurofilament reactivity was found in 14. Retina1 S-antigen was detected only in one medulloblastoma, 314 pineal tumours and 212 retinoblastomas. Reactivity. for synaptophysin was present in 215 medulloblastomas, 3/10 neuroblastomas and 212 retinoblastomas. GFAP was demonstrated in scattered tumour cells in 415 medulloblastomas. Two of these were the only tumours featuring bipolar differentiation whilst it was unipolar in the remainder. The significance of these findings in relation to the ontogeny of these tumours is discussed

Haemangioblastoma, Histological and immunohistological study of an enigmatic cerebellar tumour

Paraffin-embedded blocks of 36 cerebellar haemangioblastomas were reacted with a panel of antibodies including glial fibrillary acidic protein, vimentin, epithelial membrane antigen, cytokeratin, Factor VIII, a neuroendocrine marker and with Ulex europaeus. agglutinin The main histological features, apart from the characteristic large abnormal vessels, were a prominent reticulin network, a cystic architecture and cellular and nuclear polymorphism. Two cell types were identified: endothelial and stromal. Twenty tumours were positive for glial fibrillary acidic protein because of included or reactive astrocytes as well as positive stromal cells. Vimentin was positive in all tumours with a diffuse distribution and a somatic pattern; blood vessels, stromal cells and reactive astrocytes were strongly positive. Factor V111 and Ulex europaeus agglutinin reactivity were present in a similar pattern of staining in endothelium and in five cases there were stromal cells that were positive with the latter. We were not able to ascertain the histogenesis of the stromal cell, which remains enigmatic