Multidetector Computed Tomography Imaging Features of Inflammatory Myofibroblastic Tumors of the Gastrointestinal Tract in Adults: Radiological, Histopathological, and Immunohistochemical Features

Background: Inflammatory myofibroblastic tumors (IMTs) of the gastrointestinal (GI) tract are rare phenomena, and the computed tomography (CT) findings of GI IMTs are not well-established. Objectives: To describe the characteristics of CT scans, pathological specimens, and histological subtypes of GI IMTs in adults. Patients and Methods: The multidetector computed tomography (MDCT) scans of 11 adult patients (8 males, 3 females; age range, 19 -76 years) with pathologically proven GI tract IMTs (stomach, small bowel, and colon) were retrospectively evaluated by two ab-dominal radiologists. The radiological features of IMTs were investigated. The imaging features were correlated with three micro-scopic IMT subtypes (myxoid vascular, spindle cell, and hypocellular fibrous). Immunohistochemistry was also performed on the specimens, including smooth muscle actin (SMA), vimentin, desmin, S-100, and anaplastic lymphoma kinase. Results: The tumor size ranged from 1.4 to 15 cm (mean, 5.7 cm). Two growth patterns were classified, namely, wall-thickening (n = 3) and solitary mass-forming (n = 8) patterns; each pattern was matched with a characteristic pathological subtype. All solitary, well-circumscribed masses corresponded to the spindle cell type. Low-attenuation wall thickening with perienteric infiltration was observed in three patients with a wall-thickening pattern. All solitary, well-circumscribed masses (n = 8) showed homogeneous enhancement with variable internal low attenuation, correlated with cystic degeneration, necrosis, myxoid change (n = 6), and hemorrhagic necrosis (n = 2). No patient showed bowel obstruction, while one patient showed regional lymphadenopathy. Im-munophenotypes were not correlated with any growth pattern or histological subtype. Conclusion: The GI IMTs can be classified into two patterns, including wall-thickening and well-circumscribed masses, each matched with a characteristic pathological subtype, which can help explain the tumor behavior. Concomitant CT findings may also provide diagnostic clues for IMT.