Epithelioid inflammatory myofibroblastic sarcoma with exceptionally long response to lorlatinib-a case report.

Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is a rare and aggressive subtype of inflammatory myofibroblastic tumor. The disease is associated with rearrangements of the anaplastic lymphoma kinase (ALK). In this paper, we present the clinicopathological features and treatment of a female patient diagnosed with EIMS. In 2019, an 18-year-old female patient was admitted to the hospital with abdominal pain. Radiological examinations confirmed a large pelvic mass which was subsequently resected. After re-evaluation of the initial histologic diagnosis, the final diagnosis of EIMS was established. Consequently, due to the lack of response to chemotherapy and deteriorating clinical condition, she began the therapy with ALK inhibitors. In total, the patient was treated with crizotinib, alectinib, and lorlatinib. As a result, after over 4 years since the initial diagnosis, she is still alive with significantly improved clinical condition and quality of life. This paper demonstrates the clinical benefits of sequential therapy of ALK inhibitors and an exceptionally long response to lorlatinib, a third-generation tyrosine kinase inhibitor.