[Metastasis of uterine leiomyosarcoma to the pancreas--usefulness and limitations of EUS-FNA].

A woman in her 60's presented with a tumor of the pancreatic body. Pan-hysterectomy had been performed under a diagnosis of uterine leiomyoma 11 years previously. A sample obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) revealed the histopathological proliferation of spindle-shaped bundles of atypical cells, and immunohistochemical staining demonstrated that these cells were positive for KIT. Therefore, distal pancreatectomy was performed under a diagnosis of pancreatic gastrointestinal stromal tumor (GIST). Immunohistochemical staining of surgical specimens demonstrated that the tumor cells were positive for desmin and negative for KIT and CD34. The low-grade leiomyosarcoma in pathological specimens of the uterine myoma obtained 11 years previously histologically resembled the pathological findings of the pancreatic specimens except for atypical nuclei and mitotic cells. Therefore, the final diagnosis was extremely rare metastatic leiomyosarcoma of the pancreas. Herein, we report metastasis of uterine leiomyosarcoma to the pancreas and discuss the usefulness and limitations of EUS-FNA.