Abstract
Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal neoplasm and patients with IMT tend to have a favorable outcome after complete surgical resection. However, some tumors of IMT cases have recurred and grown rapidly after successful surgery. Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is a highly aggressive intra-abdominal IMT variant with epithelioid-to-round cell morphology. Currently, no standard therapy exists for recurrent or invasive IMTs and EIMS, but anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) are recommended for those harboring ALK gene rearrangements. We herein report the first case of PRRC2B-ALK fusion associated IMTs with clinical and pathological manifestation matched the diagnosis criteria of EIMS and the durable clinical response of the sequential use of ALK TKIs (crizotinib, alectinib, ceritinib, and lorlatinib). A female patient with EIMS of the greater omentum was suffering from a rapid recurrence after cytoreductive surgery was done. Crizotinib was administered when PRRC2B-ALK fusion was detected, and partial response was achieved. The progression-free survival (PFS) of crizotinib was 5 months. Alectinib was administered based on the results of second next-generation sequencing (NGS) analysis, which identified the secondary mutation ALK R1192P. The best overall response of alectinib treatment was a partial response (PR) and the PFS was 5.5 months. Ceritinib was prescribed as third-line therapy after alectinib resistance with ALK L1196M mutation. PR was achieved and the PFS of ceritinib was 6 months. The patient was taking lorlatinib after ceritinib resistance and achieved a stable disease at 2 months with the PFS more than 5 months. The overall survival was more than two years as of the time of manuscript preparation. We describe an EIMS of greater omentum caused by PRRC2B-ALK fusion gene and showed durable clinical response to the sequential use of ALK TKIs.
Highlights
Inflammatory myofibroblastic tumor (IMT) is extremely rare and characterized by the proliferation of myofibroblastic spindle cells with varying extent of inflammatory cell infiltrates [1]
There were no significant adverse events throughout the course of treatment. In this case we have reported a case of PRRC2B-anaplastic lymphoma kinase (ALK) fusion associated IMTs with clinical and pathological manifestation matched the diagnosis criteria of Epithelioid inflammatory myofibroblastic sarcoma (EIMS) and the benefit of the sequential use of ALK tyrosine kinase inhibitors (TKIs)
We report the case of PRRC2B-ALK fusion associated EIMS and describe the durable clinical response to sequential use of ALK TKIs
Summary
Inflammatory myofibroblastic tumor (IMT) is extremely rare and characterized by the proliferation of myofibroblastic spindle cells with varying extent of inflammatory cell infiltrates [1]. We described the case of a patient with PRRC2B-ALK associated IMT of the greater omentum, whose clinical and pathological manifestation matched the diagnosis criteria of EIMS. The patient was subsequently treated with first-generation ALK TKI crizotinib (250 mg, bid) as the first-line therapy. Two months later, her symptoms significantly improved. NGS detected the emergence of ALK R1192P (Figure 3C) and retention of PRRC2B-ALK fusion She was switched to a next-generation ALK TKI alectinib at a dose of 600 mg twice daily. After 1 month treatment, her abdominal pain was significantly alleviated with the peritoneal lesion regressed rapidly by 35.7% per RECIST (Figure 2E). New intra-abdominal biopsy was performed and NGS detected the emergence of ALK L1196M (Figure 3D) and retention of PRRC2B-ALK fusion. There were no significant adverse events throughout the course of treatment
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