Infantile inflammatory myofibroblastic tumour of the sigmoid colon: a diagnostic dilemma.

An inflammatory myofibroblastic tumour (IMT) is an uncommon neoplasm composed of inflammatory cells and myofibroblasts in a fibrous stroma. They are mostly seen in the lungs and rarely involve the gastrointestinal tract. An 8-month-old infant presented with a history of lower abdominal lump for 2 months. Her CT scan confirmed a large, lobulated mass in the retroperitoneum arising from the pelvis. The mass was found to be arising from the sigmoid colon on laparotomy which was excised. Histopathology showed a cellular tumour composed of spindle cells and inflammatory lymphocytic infiltrate. Immunohistochemistry revealed positive staining for anaplastic lymphoma kinase and smooth muscle actin, confirming the diagnosis of IMT. The patient is doing well at her 6-month follow-up. Ours is the youngest case of sigmoid IMT among the only other series of eight cases reported in the literature indicating its rarity.