Anaplastic Lymphoma Kinase Positive Aggressive Adult Lung Primary Inflammatory Myofibroblastoma Tumor: A Case and Literature Review.

Abstract

Inflammatory myofibroblastoma tumor (IMT) is a rare mesenchymal neoplasm that develops in the lungs, retroperitoneum, or abdominopelvic region, and is most common in children and adolescents; although IMT usually has a good prognosis, some cases still show local invasion, recurrence, and even distant metastasis. Effective standard treatment for locally advanced or metastatic IMT is limited, but therapy with anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) improves the prognosis in some patients with ALK protein expression or ALK gene fusions. This case reports a 39-year-old woman with recurrent fever, cough, sputum, chest tightness, and shortness of breath for more than 2 weeks. Contrast-enhanced computed tomography (CT) revealed a mass in the upper lobe of the right lung with ill-defined borders involving the mediastinum, pleura, and right hilum. Multiple pleural nodules and right-sided pleural effusion were also observed. IMT was diagnosed by lung biopsy, and ALK positive was confirmed by immunohistochemistry. The patient's lung CT was reviewed after 3 weeks of treatment with brigatinib, and the right lung lesion and multiple metastases in the right pleura, hilar region, and mediastinum were significantly smaller than before. Additionally, the right pleural effusion was reduced, and the clinical symptoms were significantly improved compared to prior evaluations. Unlike most IMT cases, this patient's tumor showed highly malignant biology, with pleural metastasis at the initial diagnosis, as well as rapid progression and a favorable response to ALK TKI. Brigatinib represents a potential therapeutic option for the treatment of IMT.