Complete response to alectinib following crizotinib in an ALK-positive inflammatory myofibroblastic tumor with CNS involvement

Abstract

Inflammatory myofibroblastic tumor (IMT) is a rare entity that affects mostly children and young adults. The lungs are the most frequent primary site. When feasible, surgical resection is the standard of care and it is associated with long-term survival benefit. Metastatic disease is rare, and central nervous system involvement is very infrequent. There is paucity of data regarding systemic treatment of recurrent or metastatic disease but most IMTs present with ALK rearrangements, becoming potential targets to ALK inhibition. Diagnosis of ALK rearrangements by FISH or RT-PCR is standard and discordant results from immunohistochemistry are rare. Crizotinib is considered the standard therapy in ALK-positive cases. Data supporting the use of other ALK inhibitors are scant and derived only from case reports. We report a case of a patient harboring an ALK-positive by IHC, FISH-negative IMT, that initially responded well to crizotinib but progressed in the CNS, presenting a complete CNS response with second-generation ALK inhibitor alectinib.

Keywords

• Lung cancer
• Inflammatory myofibroblastic tumor
• ALK-rearrangement
• Targeted therapy