Correlation between the clinical course of granulomatous meningoencephalomyelitis in dogs and the extent of mast cell infiltration

The data from 20 dogs with histopathologically confirmed granulomatous meni ngoencephelomyelitis were reviewed in an attempt to identify clinical signs and morphological and cellular parameters, particularly the infiltration o f mast cells, which might be associated with the clinical course of the dis ease. Thirteen of the dogs had the acute form of the disease and seven had the chronic form. Young to middle-aged, small breed female dogs were over-r epresented. Central vestibular signs were observed in six of the dogs with the acute disease. Analyses of cerebrospinal fluid revealed moderate to sev ere pleocytosis and high protein concentrations in all cases. Histopatholog ical investigations revealed disseminated perivascular cuffs, large conflue nt granulomata. tissue necrosis, infiltration with neutrophils and a large number of mitotic cells in the dogs with either of the clinical forms of th e disease. Tryptase-positive mast cells were observed in all the cases, but there were significantly larger numbers in the dogs with the acute form.