UNUSUAL BENIGN NEUROGENIC SOFT-TISSUE TUMOR - EPITHELIOID SCHWANNOMA OR AN OSSIFYING FIBROMYXOID TUMOR

An unusual form of subcutaneous soft tissue tumour with benign charact er is reported. The tumour was composed of uniform cells which were ep ithelioid in appearance. True myxoid matrix, osteoid formation or meta plastic bone were not present. Immunohistochemically S-100 protein and vimentin was demonstrated in the tumour cells. Electron microscopic e xamination showed fragmented or continuous basal lamina, interdigitati ng cytoplasmic projections, myelin-like figures and a few cell junctio ns. The immunohistochemical and electron microscopic results indicate that the tumour is of Schwann's cell origin. Based on light microscopi c, electron microscopic and immunohistochemical results we think our c ase is an epithelioid benign schwannoma but the non-ossifying form of fibromyxoid tumour of the soft parts cannot be excluded with confidenc e.