Abrikosov's tumour was studied light- and electron-microscopically and immunohistochemically with the use of antibodies against desmin, myoglobin, vimentin, cytokeratin, glial fibrillar acid protein, neuron-specific enolase, S-100 protein, neurofilaments (68 kd), lysozyme, alpha-1-antichymotrypsin, alpha-1-antitrypsin, structural components of extracellular matrix (collagen I, II, III, IV, V types and fibronectin). The presence of neurofilaments, apart from vimentin, S-100 protein and small amount of neurospecific enolase, in the tumour cells is demonstrated for the first time. Neurofilament expression by tumour cells and the lack of the basal membrane collagen (type IV) in the extracellular matrix indicate the cell differentiation different from that of Schwann cells. A similar cell immunophenotype is typical for tumours of sympathetic ganglion and paraganglion structures. Both these results and literature data prove phenotypic heterogeneity of the granular cell tumours and their histogenetic link with the cells of nervous comb.