Inflammatory myofibroblastic tumor on second portion of duodenum: a case report.

Inflammatory myofibroblastic tumors (IMTs) of the duodenum are exceptionally uncommon, and their epidemiologic and clinical characteristics remain poorly defined because of the limited number of reported cases. We previously reported a case of duodenal IMT in the Korean Journal of Gastroenterology in 2018, with follow-up data available only up to 12 months. IMTs typically behave in a benign manner, but they may occasionally demonstrate local invasiveness and recurrence; therefore, achieving complete surgical excision is crucial, followed by long-term surveillance. In the present manuscript, we provide a subsequent long-term follow-up report of the same patient, offering an extended 88-month postoperative course and additional radiologic and pathologic details not included in the earlier publication. This follow-up report highlights the long-term benign behavior of the tumor despite positive surgical margins and anaplastic lymphoma kinase (ALK)-negative immunohistochemistry, contributing meaningful information to the scarce literature on adult duodenal IMTs.