Rectal inflammatory myofibroblastic tumor: Case report and literature review

Rationale: Rectal inflammatory myofibroblastic tumor (IMT) is an extremely rare mesenchymal tumor characterized by a mixture of spindle-shaped myofibroblasts or fibroblasts and inflammatory infiltration of lymphocytes and plasma cells. To date, only 8 cases of rectal IMT have been reported. Herein, we report an additional case of rectal IMT in a 28-year-old woman. Patient concerns: A 28-year-old woman presented with abdominal pain and hematochezia. Diagnoses: Colonoscopy showed a 3.0-cm subepithelial tumor with central ulceration, covered by white exudate in the rectum. Rectal magnetic resonance imaging revealed a 4.0 × 3.0-cm-sized well-defined subepithelial tumor in the right wall of the rectum, with suspicious right perirectal fat infiltration. Interventions: Laparoscopic anterior resection was performed. Microscopic examination of the surgical specimen revealed bland-looking spindle cells intermingled with lymphoplasma cells. Immunohistochemistry and fluorescence in situ hybridization showed anaplastic lymphoma kinase positivity and anaplastic lymphoma kinase positivity rearrangement. Rectal IMT was confirmed based on histological, immunohistochemical, and fluorescence in situ hybridization findings. The patient was doing well without evidence of tumor recurrence 1 year after the surgery. Lessons: Rectal IMT, despite its rarity, should be considered in the differential diagnosis of rectal cancer. Second, an accurate histopathologic diagnosis and complete surgical resection can be the most important approaches to offer a chance for the cure of rectal IMT.