title: Transdifferentiation of pancreatic stromal tumor into leiomyosarcoma with metastases to liver and peritoneum: a case report.
abstract: Primary pancreatic leiomyosarcoma is a rare pancreatic malignancy; the clinical presentation and treatment is not well-characterized. Further, the molecular mechanisms underlying its pathogenesis are not known. We report a patient with pancreatic stromal tumor that progressed to primary pancreatic leiomyosarcoma with hepatic and peritoneal metastases.
  
  
  
  A 54-year-old woman was found to have pancreatic and hepatic tumor masses on routine health checkup. Owing to the difficulty in performing biopsy, this patient underwent open operation. Histopathological examination of pancreatic and liver biopsy specimen demonstrated spindle cells with nuclear mitoses. Immunohistochemical examination showed positive staining for Cluster of Differentiation117 (+) and negative staining for S-100 (-) and Smooth Muscle Actin (-). Thus, the patient was diagnosed as a case of advanced pancreatic stromal tumor with liver metastases. After surgery, treatment with oral imatinib mesylate combined with thymosin injection therapy was prescribed. Follow-up examination at 13-months revealed multiple nodular masses in liver and right peritoneum. The patient underwent a second surgery. Liver biopsy and the resected peritoneal specimen showed positive staining for Discovered On Gastrointestinal tumor-1(weak +), Actin (+), Smooth Muscle Actin (+) and negative staining for Cluster of Differentiation117 (-) Cluster of Differentiation34 (-) and S-100 (-). Histopathological examination showed spindle cells with nuclear mitoses. The final diagnosis was primary pancreatic leiomyosarcoma, transdifferentiating from pancreatic stromal tumor, with liver and peritoneal metastases.
  
  
  
  Surgery is the first line treatment for primary pancreatic leiomyosarcoma and extra-gastrointestinal stromal tumors. In the present case, radical resection was not performed owing to hepatic metastases. Palliative treatment with radioactive125I ion implantation and microwave coagulation therapy was administered. However, the long-term therapeutic effect needs to be assessed in future.
authors.affiliation: Department of Hepatobiliary and Pancreas Surgery, China-Japan Union Hospital of Jilin University, Changchun, 130033, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Lin
authors.affiliation: Department of Pathology, China-Japan Union Hospital of Jilin University, Changchun, 130033, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Wang
authors.affiliation: The Second Hospital of Jilin University, Ziqiang Street no. 218, Changchun, 130033, China.
authors.forename: Jiyao
authors.initials: J
authors.lastname: Sheng
authors.affiliation: The Second Hospital of Jilin University, Ziqiang Street no. 218, Changchun, 130033, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Department of Hepatobiliary and Pancreas Surgery, China-Japan Union Hospital of Jilin University, Changchun, 130033, China.
authors.forename: Lianyue
authors.initials: L
authors.lastname: Guan
authors.affiliation: Department of Hepatobiliary and Pancreas Surgery, China-Japan Union Hospital of Jilin University, Changchun, 130033, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Zhao
authors.affiliation: The Second Hospital of Jilin University, Ziqiang Street no. 218, Changchun, 130033, China. latml@163.com.
authors.forename: Xuewen
authors.initials: X
authors.lastname: Zhang
mesh_terms: D054338:Cell Transdifferentiation; D003131:Combined Modality Therapy / Q000379:methods; D013505:Digestive System Surgical Procedures; D004358:Drug Therapy; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000175:diagnosis* / Q000628:therapy; D006801:Humans; D007890:Leiomyosarcoma / Q000175:diagnosis* / Q000628:therapy; D008113:Liver Neoplasms / Q000556:secondary* / Q000628:therapy; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000628:therapy; D010534:Peritoneal Neoplasms / Q000556:secondary* / Q000628:therapy; D016896:Treatment Outcome
keywords: Diagnosis; Extra-gastrointestinal stromal tumor; Primary pancreatic leiomyosarcoma; Therapy