Preoperative Diagnosis of Pancreatic Leiomyosarcoma Marcel C. C. Machado,* ,1 José Eduardo M. Cunha, 1 Sonia Penteado, 1 Telesforo Bacchella, José Jukemura, 1 Anderson C. L. Costa, 2 and Ilana Halpern-Salomon 2 1 Department of Gastroenterology and 2 Department of Pathology, School of Medicine, University of São Paulo, Brazil Introduction Leiomyosarcoma of the pancreas is a very uncom- mon tumor. In a recent review of the literature, we could find only 28 cases reported. Because of the rare nature of these tumors, there are few diagnos- tic criteria to establish the preoperative diagnosis of these lesions. They may be misdiagnosed as pan- creatic pseudocyst or cystadenoma. We report a case of leiomyosarcoma of the pan- creas that had its mesenchymal nature established in the preoperative work-up before it was success- fully resected. Case Report A 52-yr-old male was admitted to our hospital with a pancreatic tumor disclosed in a routine work- up for evaluation of a possible chronic virus C hepati- tis (HCV). A positive anti-HCV was detected when the patient was evaluated as a possible blood donor. Past history was unremarkable and physical examination on admission revealed a slightly ten- der mass in the right epigastrium. It was about 10-cm wide, elastic and hard. Laboratory studies International Journal of Pancreatology, vol. 28, no. 2, 97–100, October 2000 © Copyright 2000 by Humana Press Inc. All rights of any nature whatsoever reserved. 0169-4197/00/28:97–100/$11.00 97 Case Report Received December 16, 1999; Revised April 6, 2000; Accepted April 12, 2000. *Author to whom all correspondence and reprint requests should be addressed. R. Peixoto Gomide, 515-13o andar-CJ. 134, Cerqueira Cesar, São Paulo, SP., CEP: 01409-001, Brasil. E-mail: mccm37@vol.com.br Summary Background: The low incidence of pancreatic leiomyosarcoma is responsible for the small number of cases correctly diagnosed preoperatively, the tumor being frequently confused with benign pancreatic lesions. Results: We describe a symptom free 52-yr-old male bearing an abdominal mass incidentally found at physical examination. Imaging techniques revealed a nonhomogenous large mass at the head of the pancreas that dislodged the portal vein and the superior mesenteric vein. Increased metabolic activity in the tumor area demonstrated by 18 F-fluorodeoxyglicose positron emission tomography scan allowed the diagnosis of a malignant lesion. The patient was operated on and a pylorus preserving pancreatoduo- denectomy performed. The pathology diagnosis was a low grade leiomyosarcoma. Immunohistochem- istry revealed positivity for vimentin and smooth muscle specific actin. The clinical course was uneventful after 2 yr follow-up. Conclusion: Pancreatic leiomyosarcoma may be preoperatively diagnosed by image techniques and differentiated from benign lesions by means of fluorodeoxyglicose positron emission tomogra- phy scanning (FDGPET). Key Words: pancreatic tumor; leyomiosarcoma-fluorodeoxyglicose positron emission tomography.