A rare case of maxillary sinus and buccal space involvement of extramedullary plasmocytoma: Cross-sectional imaging findings and review of the literature.

Extramedullary plasmacytoma (EMP) belongs to the group of plasma cell neoplasms, which include following entities: multiple myeloma (MM), lymphoplasmacytic lymphoma, solitary plasmacytoma of the bone (SBP) and EMP. Localization in the maxillary sinus with simultaneous involvement of the buccal cavity is rare. Misdiagnosis may lead to inappropriate or delayed management. X-ray, computed tomography (CT) scan, magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT) scan provide useful information for diagnosis. Many CT and MRI features are not specific and it is important to find specific imaging characteristics for making differential diagnosis. Our case has shown how, in the context of advanced MRI techniques, DWI is decisive in achieving the correct diagnosis of EMP The peculiarity of this case, in addition to showing the possibility, although rare, of a simultaneous involvement of EMP of the buccal cavity and of the ipsilateral maxillary sinus, presents the behavior of the EMP in various imaging methods, highlighting how diffusion-weighted imaging (DWI) played an important role to suggest the correct diagnosis and differentiating it from squamous cell carcinoma (SCC) and non-Hodgkin lymphoma (NHL).