Malignant inflammatory myofibroblastic tumor of the maxillary sinus
In January 2012, a 29-year-old apparently healthy man was admitted to the Department of Oral and Maxillofacial Pathology, with 1 month history of left facial numbness, swelling and pain radiating to the left maxillary sinus, upper teeth, and zygomatic region. Pain was severe, aggravated during the night and relieved on medication. There was no nausea, vomiting or hypopsia. Clinical examination revealed a firm, diffuse swelling involving the left midfacial area, extending into the oral cavity, accompanied by pain in the left upper teeth.\nThe patient's medical history was otherwise unremarkable. No enlarged cervical lymph node was palpable and laboratory tests suggested no significant abnormality.\nIntraorally, both right permanent maxillary premolars and the first molar were luxated. The covering mucosa was normal. There were no signs of infection such as, erythema, purulent drainage, fluctuance or indurated swelling of the surrounding soft tissues.\nAn urgent computerized tomography (CT) scan revealed a homogenous soft tissue mass involving the left maxillary sinus. The mass destructed the anterior and inferior walls and extended further downward, until the alveolar bone was destroyed. Furthermore, cortex was destroyed from both buccal and palatal sides. No obvious calcification or ossification was noted []. The clinical and radiological impression was one of a malignant maxillary sinus tumor.\nThe patient therefore underwent an excisional biopsy via an extraoral approach under general anesthesia. The intraoperative findings revealed a highly vascular, friable lesion occupying the left maxillary sinus. The whole mass was excised.\nHistopathologically, this tumor was composed of diffuse storiform proliferation of spindle-shaped fibroblasts and myofibroblasts in a predominantly fibromyxoid stroma interspersed with dense bands of collagen. This was accompanied by inflammatory cells which included lymphocytes, plasma cells, and foamy histiocytes [Figures and ]. Mitotic figures were rare, but the cellularity of the tumor together with hyperchromatism, variations in the size of nuclei and the invasive quality of the tumor, indicated malignancy.\nImmunohistochemical analysis revealed that the spindle-shaped cells were strongly and diffusely positive for vimentin, smooth muscle actin, anaplastic lymphoma kinase (ALK), and revealed a high proliferative index (Ki-67 = 60%) []. None were positive for desmin, pancytokeratin, S-100 protein, CD57, CD34, and CD68. All immunohistochemical studies that have been performed are summarized in . Special stains revealed no acid fast bacilli, other microorganisms or foreign materials.\nOn the basis of the above histopathologic and immunohistochemical findings, a diagnosis of IMT with malignant transformation was established. There was no clinical evidence of local or distant metastatic spread.\nThe patient was referred to an oncologist for further treatment. As the patient did not keep his appointment with the dental school, no additional follow-up information is available.