Table 1 Clinical and pathological features to consider before diagnosing inflammatory myofibroblastic tumour (IMT)
| Features that favour IMT | Features that argue against IMT | |
| Child or young adult | Middle-aged or older adult | |
| Mass in lung or soft tissue of abdomen, pelvis, or retroperitoneum | Mass in skin or subcutis, lymph node, spleen, or bladder | |
| Diffuse inflammatory infiltrate with prominent plasma cells | Patchy, predominantly lymphocytic inflammatory infiltrate | |
| Mild nuclear atypia including scattered ganglion-like cells | Moderate to severe nuclear atypia with hyperchromasia | |
| Low mitotic rate without atypical forms | Atypical mitoses | |
| ALK positivity by immunohistochemistry or ALK gene rearrangement | Necrosis |
