Reclassification of a spindle cell sarcoma after identification of a TFG-ROS1 fusion: A case demonstrating the clinical benefit of next-generation sequencing in sarcoma

BACKGROUND

Inflammatory myofibroblastic tumors (IMTs) are rare mesenchymal soft tissue sarcomas that often present diagnostic challenges due to their wide and varied morphology. A subset of IMTs have fusions involving ALK or ROS1. The role of next-generation sequencing (NGS) for classification of unselected sarcomas remains controversial.

METHODS AND RESULTS

We report a case of a metastatic sarcoma in a 34-year-old female originally diagnosed as an unclassified spindle cell sarcoma with myofibroblastic differentiation and later reclassified as IMT after NGS revealed a TFG-ROS1 rearrangement. Histologically, the neoplasm had spindle cell morphology with a lobulated to focally infiltrative growth pattern with scant inflammatory cell infiltrate. Immunohistochemistry demonstrated focal desmin and variable smooth muscle actin staining but was negative for SOX10, S100, and CD34. Fluorescence in situ hybridization was negative for USP6 or ALK gene rearrangements. NGS revealed a TFG-ROS1 rearrangement and the patient was treated with crizotinib with clinical benefit.

CONCLUSIONS

We discuss the role of NGS as well as its potential benefit in patients with unresectable, ALK-negative metastatic disease. Considering this case and previous literature, we support the use of NGS for patients requiring systemic treatment.

Inflammatory Myofibroblastic Tumor (IMT) of the Trachea Excised by Transtracheal Surgery: Case Report

This report describes an extremely rare case of a primary inflammatory myofibroblastic tumor of the trachea. The patient underwent surgical resection by a transtracheal approach and reconstruction with esophageal tracheoplasty. This case report highlights the rarity of such tumors and a minimally invasive and safe surgical technique for tumors around the central neck structures.

Inflammatory myofibroblastic tumor of the thyroid gland

Inflammatory myofibroblastic tumor (IMT) is a mesenchymal tumor with low incidence, which is extremely rare in the thyroid. At present, there is a lack of understanding regarding the etiology, pathogenesis, diagnosis and treatment of thyroid IMT. To improve the understanding of the disease, this article reviews the pathogenesis, clinical manifestations, pathology and immunohistochemistry, diagnosis, therapy and prognosis of thyroid IMT.

Ultrasonic Manifestations of Mesenteric Inflammatory Myofibroblastic Tumors in Children

Objective: To explore the ultrasonic manifestations of mesenteric inflammatory myofibroblastic tumors (IMTs) in children. Methods: Seven patients with mesenteric IMTs were retrospectively analyzed. The ultrasonic manifestations, such as the locations, sizes, morphology, borders, internal echo, blood flow, and metastasis, of the tumors were detected. Results: In all the seven pediatric patients, a solitary lesion was found for the mesenteric IMTs, including five cases in the ileocecal mesentery and two cases in the mesentery of ascending colon. All the single tumors were revealed as irregular hypoechoic masses with uneven internal echoes and enhanced echoes in the surrounding intestine and omentum. Internal blood flow signals were enriched in the tumors. The borders were clear in five cases and unclear in two cases. In addition, two cases had peritoneal effusion and one case had calcified plaques. In the follow-up studies, one of the seven IMT patients had malignant transformation, and one case was transferred to the pelvic cavity. Conclusion: Ultrasonic examination can clearly demonstrate the locations, sizes, morphology, borders, internal echo, blood flow as well as metastasis of the pediatric IMT of the mesentery, having an important clinical application value as an adjunct to computed tomography (CT).

Crizotinib in ALK+ inflammatory myofibroblastic tumors-Current experience and future perspectives

Inflammatory myofibroblastic tumor (IMT) and its subtype epithelioid inflammatory myofibroblastic sarcoma (EIMS) are rare soft-tissue tumors. As about 50% of IMT and 100% of EIMS contain activating rearrangements of the anaplastic lymphoma kinase (ALK) gene, targeted kinase inhibition of ALK by compounds such as crizotinib is a potential treatment option. We performed a literature review and analyzed a total of 30 patients with IMT/EIMS treated with crizotinib. A total of 12 patients achieved complete or partial remission. As preliminary data are promising, a prospective study evaluating crizotinib treatment in patients with unresectable/multifocal ALK⁺ IMT/EIMS is warranted.