title: Malignant islet cell tumor with sarcomatous differentiation.
abstract: Malignant mesenchymal neoplasms of the pancreas are rare and malignant islet cell tumors with sarcomatous dedifferentiation are rarer still. We present a case of malignant islet cell tumor with sarcomatous differentiation, which to our knowledge is only the second reported case showing such a combination of morphologic features. Clinically, the neoplasm was not hormonally active and immunohistochemical staining was negative for gastrin, glucagon, insulin and somatostatin. The sarcomatous component strongly reacted with an antibody directed against vimentin, and a minority of cells stained strongly with antisera directed against desmin and smooth muscle actin. The spindle cell component was nonreactive with antibodies directed against Factor VIII. The myogenous direction of differentiation in the present tumor is similar to that seen in the prior case report of malignant islet cell tumor with rhabdomyosarcomatous differentiation.
authors.affiliation: Department of Pathology, School of Medicine, University of Utah Health Sciences Center, 50 North Medical Drive, Salt Lake City, UT 84132, USA.
authors.forename: L
authors.initials: L
authors.lastname: Emerson
authors.forename: L J
authors.initials: LJ
authors.lastname: Layfield
authors.forename: R
authors.initials: R
authors.lastname: Reiss
authors.forename: S
authors.initials: S
authors.lastname: Mulvihill
authors.forename: J
authors.initials: J
authors.lastname: Holden
mesh_terms: D000199:Actins / Q000032:analysis; D007516:Adenoma, Islet Cell / Q000378:metabolism / Q000473:pathology*; D000951:Antigens, Neoplasm; D002454:Cell Differentiation; D004250:DNA Topoisomerases, Type II / Q000032:analysis; D004268:DNA-Binding Proteins; D003893:Desmin / Q000032:analysis; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D009130:Muscle, Smooth / Q000737:chemistry; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D012509:Sarcoma / Q000378:metabolism / Q000473:pathology*
chemical_list: D000199:Actins; D000951:Antigens, Neoplasm; D004268:DNA-Binding Proteins; D003893:Desmin; D004250:DNA Topoisomerases, Type II