[Mesenchymal tumors of the pancreas. Surprising, but not uncommon].

Mesenchymal tumors of the pancreas are rare. They are resected because a solid or cystic pancreatic tumor is suspected. Benign mesenchymal tumors comprise lymphangiomas, hemangiomas, schwannomas, solitary fibrous tumors, adenomatoid tumors, clear cell tumors, and hamartomas. Inflammatory pseudotumors are a special case. Malignant mesenchymal tumors include leiomyosarcomas, malignant peripheral nerve sheath tumors (MPNST), liposarcomas, malignant fibrous histiocytomas, Ewing's sarcomas, and primitive neuroectodermal tumors (PNET). It is important to differentiate these tumors from anaplastic carcinomas and retroperitoneal tumors that infiltrate pancreatic tissue.