Patient went on to have a biopsy.
MICROSCOPIC DESCRIPTION:Paraffin sections show dense infiltration of dura by a mixed cellular infiltrate. This is composed predominantly of lymphocytes lacking atypical features as well as plasma cells and monocyte macrophages. There is proliferation of small calibre vascular channels with swollen lining endothelium. Granulomas are not identified. There is no evidence of haemophagocytosis by monocyte macrophages. No eosinophils are identified.
Immunohistochemistry shows the lymphocytic infiltrate is a mixture of B and T cells. No CD30+ cells are seen. There is no immunostaining for IgG4 or CD1a and EBER-CISH is negative. The features are of non-specific pacchymeningitis. No evidence of tumour is seen.
FINAL DIAGNOSIS: Non-specific pachymeningitis; no evidence of tumour seen.