PMC4474970_01
CT imaging findings. a Axial non-contrast CT image shows a 31 x 43 x 46-mm mass in the left maxillary sinus and masticatory space with resorption and destruction of the maxillary sinus posterior bone. b Coronal CT (bone-window) images show diffuse and partial resorption of the alveolar bone and elevation of the posterior maxillary sinus floor with destruction of the floor and lateral side wall
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Fig1
Non-contrast CT revealed a 31 x 43 x 46-mm mass in the left maxillary sinus and masticatory space, with posterior bone resorption and destruction of the maxillary sinus (Fig. 1a). The solid mass also showed partial resorption of the alveolar bone and elevation of the posterior maxillary sinus floor with destruction of the floor and lateral side wall (Fig. 1b).
MRI findings. a Axial T2-weighted MR image shows heterogeneous hyperintensity with a prominent high-signal spot of the solid mass in the left maxillary sinus and masticatory space. b Axial contrast-enhanced T1-weighted MR image shows strong and heterogeneous enhancement of the mass
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Fig2
T2-weighted fast spin-echo images (TR/TE = 4452/100 ms) (Fig. 2a), and high signal intensity on diffusion-weighted imaging (DWI) (b value = 0 and 1000 s/mm2), reflecting restricted diffusion. T1-weighted spin-echo images (TR/TE = 554/10 ms) enhanced with gadolinium-diethylene-triamine-pentaacetic acid (Gd-DTPA) (Magnevist: Bayer Schering Pharma, Osaka, Japan) showed strong and heterogeneous enhancement of the tumor (Fig. 2b). These findings of marginal bone destruction by the lesion on CT and MRI and abnormal signal intensity on DWI suggested a malignant tumor, and we first suspected ameloblastic carcinoma. The differential diagnosis included malignant peripheral nerve sheath tumor, rhabdomyosarcoma, pleomorphic adenocarcinoma or adenoid cystic carcinoma arising from the masticatory space.
Findings of 18F-FDG PET/CT imaging. a PET and b fused PET/CT imaging show that the mass has mild FDG uptake with a maximum standardized uptake value (SUVmax) of 2.40
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Fig3
The mass showed mild FDG uptake with a maximum standardized uptake value (SUVmax) of 2.40 (Figs. 3a,b).
Histopathological findings. a Gross pathological view demonstrates a shiny white solid mass. b Microscopic view with hematoxylin and eosin staining reveals dense proliferation of follicular structures made up of tumor cells resembling odontogenic epithelium. Tall columnar cells resembling ameloblastoma cells surround peripheral follicles, which contain stellate reticulum-like central areas
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Fig4
Gross pathological review revealed a shiny white solid mass (Fig. 4a). Tall columnar cells resembling ameloblastoma cells formed arrays surrounding peripheral follicles, which contained a stellate reticulum-like component in the central area (Fig. 4b).