A Rare Case of Incidentally Diagnosed Pulmonary Inflammatory Myofibroblastic Tumour with Dramatic Response to Crizotinib in a Postpartum Woman

INTRODUCTION: Inflammatory myofibroblastic tumours are rare neoplasms which most commonly affect children and young adults. With an intermediate malignant potential, they are typically detected in the abdomen, lung, mediastinum, head and neck, gastrointestinal tract, and genitourinary tract. CASE DESCRIPTION: We describe the case of a 33-year-old postpartum woman incidentally diagnosed with a pulmonary inflammatory myofibroblastic tumour following complaints of poorly controlled hypertension a week after caesarean section. She was ALK-negative and received an ALK inhibitor with complete resolution of the lesion. A ROS1–TFG fusion confirmed the diagnosis of an inflammatory myofibroblastic tumour after CT-guided fine needle aspiration. DISCUSSION: This case highlights an uncommon presentation posing a diagnostic and therapeutic challenge and the potential treatment option of crizotinib. LEARNING POINTS: Inflammatory myofibroblastic tumour (IMT) is a rarely reported neoplasm arising in the abdominal soft tissues, the lung, mediastinum, head, neck, gastrointestinal tract, and genitourinary tract, with intermediate malignant potential. IMT is definitively diagnosed only after histological examination following surgical biopsy, based on immunohistochemical markers and the molecular characteristics of the tumour, but small biopsies may have a role in a large lesion. IMT did not cause any complications during gestation. Therapeutic approaches include surgical resection and chemotherapy, including with crizotinib, an ALK tyrosine kinase inhibitor.