Multiple anaplastic lymphoma kinase-positive primary inflammatory myofibroblastic tumors with spontaneously expanding and shrinking nodules in both lungs: a case report.

Background: Inflammatory myofibroblastic tumors (IMTs) are uncommon neoplasms most prevalent in individuals under 40 years old and predominantly in the lungs. Despite their rarity, multiple anaplastic lymphoma kinase (ALK)-positive IMTs, especially those of various sizes, have not been widely reported. This report describes a case of multiple ALK-positive IMTs in the lungs, aiming to further our understanding of their behavior and management.

Case Presentation: Herein, we present the case of a 64-year-old woman who presented with an abnormal shadow on chest examination. Chest computed tomography revealed a main tumor in the right middle lobe and multiple irregularly shaped small nodules in both lungs. Thus, thoracoscopic wedge resection of the left lower lobe was performed for diagnosis. Pathological findings indicated smooth muscle proliferation without malignancy. IMT was diagnosed following thoracoscopic right middle lobectomy. Twenty months postoperatively, one residual nodule shrank, but another grew.

Conclusions: This is the first report of multiple ALK-positive IMTs in both lungs, highlighting the need for definitive diagnosis and treatment of IMTs based on surgical resection. Although caution is required in patients with lymph node metastases or distant metastases, careful follow-up is acceptable unless there is a tendency for nodules to increase in size on imaging.