title: Ewing's sarcoma of the lesser sac masquerading as a pancreatic tumor.
abstract: Extraosseous Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) is an uncommon, aggressive, and malignant tumor with a poor patient outcome. Its occurrence in the lesser sac is a rare event and to the best of our knowledge, has not been previously described. The present case was clinically and radiologically misdiagnosed as a pancreatic tumor/gastrointestinal stromal tumor. Histopathology revealed a tumor with "small round cells" that were positive for CD99, confirming the diagnosis of ES/PNET. This report highlights the importance of considering Ewing's sarcoma in the differential diagnosis of intraabdominal, extraintestinal masses.
authors.affiliation: Department of Pathology, Kasturba Medical College, Karnataka, India.
authors.forename: Lakshmi
authors.initials: L
authors.lastname: Rao
authors.forename: Vidya
authors.initials: V
authors.lastname: Monappa
authors.forename: Gabriel
authors.initials: G
authors.lastname: Rodrigues
authors.forename: B P
authors.initials: BP
authors.lastname: Suresh
mesh_terms: D000071443:12E7 Antigen; D015703:Antigens, CD / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis; D001706:Biopsy; D015815:Cell Adhesion Molecules / Q000032:analysis; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D018241:Neuroectodermal Tumors, Primitive, Peripheral / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology / Q000628:therapy; D010190:Pancreatic Neoplasms / Q000175:diagnosis*; D010534:Peritoneal Neoplasms / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology / Q000628:therapy; D011237:Predictive Value of Tests; D012512:Sarcoma, Ewing / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology / Q000628:therapy; D014057:Tomography, X-Ray Computed
chemical_list: D000071443:12E7 Antigen; D015703:Antigens, CD; D014408:Biomarkers, Tumor; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules