Many benign and malignant sinonasal tumours have been described.
sinonasal tumours are rare,
and sinonasal cancers represent less than 5% of head and neck tumors and less than 1% of all malignancies,
with a peak incidence in the 5th to 7th decades and with a male preponderance.
The early symptoms and imaging findings of sinonasal tumours are similar to rhinosinusitis.The are neglected both by the patients and doctors.
At the time of correct diagnosis,
more than half of the tumours have reached an advanced stage with a poor prognostic outcome.
Epidermoid tumors are the most frequent tumors: epidermoid carcinoma,
adenoid cystic carcinoma.
Other rare histological types could be met (melanoma,
Even if some sinonasal tumours have specific features and the location of origin can be seen on computed tomography (CT) and magnetic resonance (MR) imaging,
only histopathologic examination can lead to the correct diagnosis.
CT is the gold standard imaging method for tumor staging and preoperative tumor mapping.It is used with higher radiation dose and intravenous contrast .
CT is also the best way to evaluate bony changes such as cortical erosion,
sclerosis and thickening of bone.
Slice thickness as low as 1 mm and reformatting in three planes is mandatory are recoimmanded for estimating bone changes.
Key areas to carefully evaluate on CT are the bony orbital walls,
posterior wall of the maxillary sinus,
and the posterior table of the frontal sinus.
MR imaging is complementary to CT to specify the soft tissue components of the tumor and to precise the extent of tumor invasion beyond the bony sinus walls.
The basic MR protocol in imaging sinonasal tumours is unenhanced T1 and T2 with the purpose of discriminating between different soft tissue structures in the tumour and mucous or fluid-filled sinuses.
Unenhanced T1 is also optimal for evaluating tumor interruption of the signal void cortical bone or low tumour signal into the high signal fatty bone marrow of the skull base.
Contrast-enhanced axial and coronal T1 with fat saturation is important for further characterization of soft tissue structures.
Diffusion weighted (DW) MR imaging is also valuable to distinguish the tumor from surrounding oedema.
MR imaging is also used to detect perivascular and perineural spread as well as orbital and dural tumour invasion.
Dural invasion is indicated when dural thickening is more than 5 mm or there is pial enhancement or focal dural nodules.