Intestinal natural killer/T-cell lymphoma presenting as a pancreatic head space-occupying lesion: A case report.

Background: Intestinal natural killer/T-cell lymphoma (NKTCL) is a rare and aggressive non-Hodgkin's lymphoma, and its occurrence is closely related to Epstein-Barr virus infection. In addition, the clinical symptoms of NKTCL are not obvious, and the specific pathogenesis is still uncertain. While NKTCL may occur in any segment of the intestinal tract, its distinct location in the periampullary region, which leads clinicians to consider mimics of a pancreatic head mass, should also be addressed.