title: Primary omental tumor with ultrastructural features of cellular schwannoma and absence of S-100 antigen reactivity.
abstract: We report a primary well-delimited, large mesenchymal omental neoplasm which appeared in a 58 year old man without neurofibromatous traces. The histological and ultrastructural features were consistent with a Schwann cell origin. However, repeated immunohistochemical reactions failed to demonstrate protein S-100 antigen reactivity in the neoplastic cells, the latter only expressing vimentin. The differential diagnosis with hemangiopericytoma is proposed.
authors.affiliation: Dept. of Pathology, Medical School, University of Valencia, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Martorell
authors.forename: M C
authors.initials: MC
authors.lastname: Calabuig
authors.forename: A
authors.initials: A
authors.lastname: Llombart-Bosch
authors.forename: J
authors.initials: J
authors.lastname: Esquerdo
mesh_terms: D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009442:Neurilemmoma / Q000378:metabolism / Q000648:ultrastructure*; D009852:Omentum / Q000473:pathology*; D010534:Peritoneal Neoplasms / Q000473:pathology*; D009418:S100 Proteins / Q000378:metabolism*
chemical_list: D009418:S100 Proteins