Clinicopathological Analysis and Treatment of Adult Patients with Inflammatory Myofibroblastic Tumor: A 15-Year Single-Center Study

Abstract

Purpose Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal malignancy that occurs primarily in children and adolescents. The clinical and pathological features of IMT in adult patients are not well understood.Materials and Methods We retrospectively searched for records of adult patients with IMT at Fudan University Shanghai Cancer Center from 2006 to 2021. Clinicopathological data, treatments, and outcomes were collected and analyzed.Results Thirty adult patients with IMT, mostly women (60.0%), were included. The median age of the patients was 38 (21-77). The most common primary site was abdominopelvic region (53.3%), followed by lungs (20.0%). Seven patients had an abdominal epithelioid inflammatory myofibroblast sarcoma (EIMS). The positivity rate of anaplastic lymphoma kinase (ALK) was 81.5% (22/27). Sixteen patients with advanced ALK-positive disease received crizotinib, with an objective response rate (ORR) of 81.3% and a disease control rate of 87.5%. The median progression-free survival was 20.8 months. EIMS was associated with more aggressive behavior; however, the prognosis was similar to that of non-EIMS patients after treatment with an ALK inhibitor. At a median follow-up time of 30 months (95% confidence interval [CI], 13.6 to 46.4), the 5-year overall survival was 77% (95% CI, 66 to 88) in all patients.Conclusion Adult IMTs appeared more aggressive, with a higher incidence of recurrence and metastases, and patients with EIMS had more aggressive cases. Treatment with ALK inhibitors resulted in a high ORR and a durable response, which suggested that ALK inhibitors could be used as a first-line treatment option in adult patients with ALK-positive advanced IMT.