Imaging characteristic features of sinonasal lymphoepithelial carcinoma and comparison with functional MRI parameters of olfactory neuroblastoma / 中华放射学杂志

ABSTRACT

Objective:To investigate the CT and MRI features of sinonasal lymphoepithelial carcinoma (LEC) and to compare functional MRI index of LEC with olfactory neuroblastoma (ONB) in this area.Methods:The clinical data, CT and MRI conventional findings of 7 patients were retrospectively reviewed . All of the patients, 5 males and 2 females, with age of 35-58 (45±9) years old, were histologically diagnosed as LEC of sinonasal tract at Beijing Tongren Hospital, Capital Medical University from February 2014 to November 2019. The semi-quantitative DCE-MRI parameters and ADC value were measured and compared with 18 cases of ONB which were collected during the same period. Independent sample t test or corrected t test, Fisher′s exact test were performed to compare the differences between the two groups. Results:In all of the 7 LEC patients, 6 lesions were located in naso-ethmoid area, 1 lesion was located in naso-orbital area. Six lesions were on the left side, and another one was sitted on both sides. All tumors manifested irregular soft tissue density with bony destruction, 3 of them showed bony sclerosis. All lesions showed homogeneous density or signal and obvious enhancement in solid portion accompanied with varying degrees of local invasion. Morphologically, two forms were observed: localized soft tissue mass and diffuse infiltration along mucosa. There were polypoid strips ( n=3), spherical masses ( n=3), and diffuse thickening of nasal cavity and turbinate mucosa ( n=1). DCE-MRI examinations were performed in six LEC patients. Maximum contrast enhancement index (CI max) was 1.51±0.46, wash out ratio (WR) was 14.26%±6.24%. Time intensity curve (TIC) showed a plateau pattern (type Ⅱ) in 4 cases and a washout pattern (type Ⅲ) in 2 cases. Time to peak (T peak) were (40.09±4.59)s, showing a rapid peak performance. Diffusion weighted imaging was performed in six LEC patients, and the ADC value was (0.80±0.14)×10 -3 mm 2/s. There were statistical differences in WR and ADC values between sinonasal LEC and ONB ( t=4.873, P=0.020 and t=3.255, P=0.025). Conclusion:The radiological manifestations of LEC have certain characteristics. The characteristics of conventional imaging findings and functional MRI index combined with clinical data are helpful in making differential diagnosis between LEC and other sinonasal malignant tumors.