| Objectives: To analyze the clinical data and conventional MRI imaging features in palatal benign and malignant tumors and tumor-like lesions and evaluate the value of conventional MR imaging in differentiating benign palatal lumps from malignant lumps and find the crucial imaging features.Methods: The clinical data and conventional MR imaging findings of 105 patients of palatal tumors and tumor-like lesions confirmed by histopathology from January 2009 to October 2016 were retrospectively reviewed.Imaging findings of the location,size,margin,morphology,signal intensity,cystic/necrosis,degree of enhancement,capsule,adjacent structures,perineural spread and metastatic lymph nodes were assessed.The clinical data in palatal benign and malignant tumors and tumor-like lesions were compared by independent-samples t-test.The data of conventional MRI imaging features in palatal tumors were analyzed by chi-square test.The variables that were statistically significant between groups for differential diagnosis were further analyzed with logistic regression.Results: A total of 105 patients(76 males,29 females,age: 53±17.1 years)including 76 malignant tumors,29 benign tumors and tumor-like lesions were enrolled.(1)the majority of malignancy in the palate was squamous cell carcinoma(51/76,67.11%)while pleomorphic adenoma(17/29,58.62%)was the most common benign palatal tumors and tumor-like lesions.The age of malignant group(57±15.9 years)was larger than that in benign group(44±17.9 years).The age and gender differences between two groups of patients represented specific statistical significance(P<0.05).(2)Most malignant tumors(52.63%)manifested as ill-defined masses with irregular or plaque-like shapes(89.65%),while the benign tumors or tumor-like lesions(58.62%)manifested as well-defined masses with round or oval shapes.The difference of the margin and morphology between two groups was statistically significant(P<0.001).Inbenign group,low signal capsular structure(20/29,68.96%)was found in 20 patients,including 15 pleomorphic adenomas.the difference was statistically significant between groups(P<0.001).(3)The invasion of adjacent structures and bone destruction were more common seen in the malignant group(45/76,59.21%)than that in benign group(3/29,20.34%)with statistically significance(P<0.05).13 malignant tumors demonstrate perineural spread(13/76,17.10%),including 7 squamous cell carcinomas,2 adenoid cystic carcinomas,4 mucoepidermoid carcinomas,while perineural involvement was not found in benign group.The difference was statistically significant between two groups(P<0.05).(4)In malignant group,lymph node enlarged(19/76,25.00%)was showed in 19 patients,including 10 patients with lymph node internal necrosis(10/76,13.15%).lymph nodes enlargement without necrosis(3/29,10.34%)were also showed in benign tumor and tumor-like lesions.The difference between two groups of lymph node necrosis was statistically significant(P<0.05).However,the size,morphology and boundary of lymph node show no significant difference(P>0.05).(5)Logistics regression analysis showed that lesion margin,capsule and the age of onset were the important factors in differential diagnosis,especially the ill-defined margin(?=4.724;OR=112.648).The existence of those influential features,the sensitivity and specificity of the forecast malignant tumors is 100% and 99.4%,respectively.Conclusion:(1)The age of palatal malignant tumors are larger than that in benign tumors,and more common in male patients.(2)The conventional MRI features such as palatal tumor morphology,boundary,capsule,adjacent structures invasion,perineural spread and lymph node necrosis are helpful in the differential diagnosis of benign and malignant tumors.(3)The margin,capsule of lesions and the age of patients has the most important value in the differential diagnosis of benign and malignant palatal lesions.When the palatal lesions appear signs with ill-defined margin,without a capsule,or with older age,the diagnosis is highly suggestive of malignant tumors. |
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