Inflammatory Myofibroblastic Tumor With Rapid Recurrence and Distant Metastasis: Report of a Rare Case

Inflammatory myofibroblastic tumors (IMTs) are rare spindle cell tumors clinically, morphologically, and genetically heterogeneous, mimicking many other reactive and neoplastic lesions and creating great diagnostic problems. Although it is generally characterized by oncogene-derived proliferation of myofibroblasts in a background of polyclonal inflammatory cell infiltrates, morphological variations do occur requiring immunohistochemistry and molecular genetics to confirm the diagnosis. It encompasses a wide age range, and locations, mostly said to be of intermediate grade having a low risk of recurrence and metastasis. However, its biological behavior and course are variable and unpredictable. Here, we report a case of thoracic IMT in a 32-year-old adult female presenting with a history of fever, cough, and chest pain associated with neutrophilic leukocytosis. Radiological investigations revealed a large mass in the thoracic region with possibilities of hydatid cyst and neurogenic tumor. Initial core needle biopsy specimen and subsequent local resection specimen revealed the diagnosis of IMT on histopathology and immunohistochemistry, having conventional morphology with expression of Anaplastic lymphoma kinase (ALK) protein. The patient developed rapid local recurrence and was started with first-generation ALK inhibitor Crizotinib. After a brief period of response, she developed vertebral and brain metastasis within a short span of time and was switched to a third-generation ALK inhibitor, Lorlatinib. The patient is on regular follow-up, has stable disease, and maintains a good quality of life after two years of diagnosis.