Neuroendocrine differentiation in the glandular peripheral nerve sheath tumor. Pathologic distinction from the biphasic synovial sarcoma with glands.

We studied eight glandular peripheral nerve sheath tumors and seven biphasic synovial sarcomas with glands with the objectives of (a) characterizing the nerve sheath tumors, especially with respect to a possible neuroendocrine differentiation, and (b) identifying features that could be used to distinguish between the two lesions. In a mainly immunohistochemical study, neuroendocrine differentiation of glandular cells was observed in five of eight (62.5%) nerve sheath tumors. The neuroendocrine cell markers found included chromogranin (five of eight cases), serotonin (four of seven cases), pancreatic polypeptide (two of five cases), and gastrin (two of six cases). These findings--together with histological, histochemical, and ultrastructural observations made in this and in other studies--point to a foregut type of intestinal differentiation for the glands in a majority of glandular peripheral nerve sheath tumors. Specific histological and immunohistochemical differences between the nerve sheath tumors and the synovial sarcomas were identified. The main histological differences were a sharp distinction between the spindle and glandular cells of the former but not the latter lesion, and the presence of goblet-type cells only in the glandular peripheral nerve sheath tumors. Major immunohistochemical differences included neuroendocrine differentiation and reactivity for S-100 protein and CEA (seen only or mainly in the nerve sheath tumors), and the reactivity of spindle cells of only the biphasic synovial sarcomas for epithelial membrane antigen.