Intraosseous inflammatory myofibroblastic tumor of the mandible with a novel ATIC-ALK fusion mutation: a case report

Abstract

BackgroundInflammatory myofibroblastic tumor (IMT) is a rare low-grade malignant neoplasm with a predilection for children and young adults, and typically arises in the lung, abdominopelvic region, and retroperitoneum. IMTs in the maxillofacial region are extreme rare. Approximately 50% of IMT harbor rearrangements of the anaplastic lymphoma kinase (ALK) gene at 2p23 with various fusion partners.Case presentationWe herein report a case of intraosseous IMT of the mandible with a novel ATIC-ALK fusion. Tooth 43 did not erupt after the loss of tooth 83 in an 11-year-old girl with no previous history of trauma. Panoramic tomography showed a unilocular radiolucent lesion in the right anterior mandible resorbing the root of tooth 42 and the medial side of the root of tooth 44. Computed tomography revealed a well- circumscribed 3-cm osteolytic lesion of the right anterior mandible eroding the buccal cortical plate. The entire lesion was curetted out. A histopathological examination revealed the proliferation of plump spindle cells with a storiform architecture and lymphocytes scattered around spindle cells. The spindle cells showed diffuse cytoplasmic staining for ALK by immunohistochemistry. A fluorescence in situ hybridization analysis revealed the translocation of a part of the ALK gene locus at chromosome 2p23. A rapid amplification of cDNA ends analysis confirmed the rearrangement of ALK and identified ATIC as a partner of this ALK fusion mutant.ConclusionTo the best of our knowledge, this is the first case of intraosseous IMT of the mandible with a novel ATIC-ALK fusion. We also herein reviewed similar tumors reported in the literature.

Clinical, morphogical and immunohistochemical aspects of oral inflammatory myofibroblastic tumor: a rare case report in a pediatric patient

“…Other treatment modalities include radiotherapy, chemotherapy, curettage, and prescription of steroids. Even though our patient had no sign of malignancy or relapse, long-term monitoring was considered to be mandatory given the fact that IMT can sometimes behave as malignant tumors 2 . In our case, we chose to perform enucleation of the lesion.…”

“…The etiology of IMT remains unclear, but factors such as trauma, infection by the Epstein-Barr virus, and alterations in the ALK gene have been associated with its occurrence 2,7,8 . This tumor has also been associated with human herpes virus 8 (HHV-8) as well as bacterial and fungal infections 9 .…”

“…Inflammatory myofibroblastic tumor (IMT) is an uncommon benign lesion composed by spindleshaped fibroblasts or myofibroblasts. It also contains a varying number of chronic inflammatory cells, mainly plasma cells and lymphocytes [1][2][3] . This lesion was first described in 1905 as being an inflammatory pseudotumor (IPT).…”

“…Although several pathological factors have been suggested (reactive, infectious, autoimmune or neoplastic), the etiology of IMT remains unknown 2 . Despite being a lesion more commonly found in the lungs, extrapulmonary IMT has also been reported in most organs and areas of the body including head and neck 1,4,5 .…”

“…The behavior of this tumor is quite variable since it may resemble either reactive lesions or benign neoplasms. Some may indeed grow very aggressively, and display typical characteristics of malignancy 2 . Oral IMT has a nonspecific clinical appearance, and a rapid growth rate both of which can clinically and radiographically be regarded as signs of malignancy.…”