腮腺肿瘤的MRI诊断

MRI manifestations of parotid tumors

目的分析腮腺肿瘤的MRI特征。方法回顾性分析46例经手术病理证实的腮腺肿瘤患者(良性32例,恶性14例)的MRI表现。结果 10例混合瘤T2WI以高、稍高混杂信号为主。11例腺淋巴瘤T1WI、T2WI均以低或稍低信号为主,内可见少许斑点状高信号。2例嗜酸细胞腺瘤中,1例表现为双侧腮腺内多发小结节;另1例为腮腺内单发肿块,术前误诊为恶性肿瘤。9例腮腺恶性肿瘤形态不规则,T2WI呈低、稍低信号,其中5例侵犯腮腺周围结构及颅底骨质,具有明显侵袭性。1例腮腺腺样囊腺癌仅表现为左侧腮腺浅叶小结节,边缘稍毛糙。1例淋巴上皮性病变恶变术前误诊为腺淋巴瘤。1例腮腺基底细胞癌呈明显囊实性肿块。1例外周型原始神经外胚层肿瘤及1例腮腺淋巴瘤表现为右侧腮腺多发软组织肿块。结论腮腺肿瘤的MRI表现有一定特点,大多数病例术前可明确诊断。

Objective To analyze MRI manifestations of primary parotid tumors. Methods MRI findings of 46 patients with pathologically proved parotid rumors （32 benign and 14 malignant tumors） were retrospectively reviewed. Results Ten pleomorphic adenomas showed high or slightly high signal intensity on T2WI. Eleven Warthin＇s tumors showed low or slightly low signal intensity on TlWI and T2WI with spotted high intensity within the tumors. One of two oncocytomas showed multiple small nodules, and the other showed a solitary mass which were misdiagnosed as malignant tumor. Nine malignant tumors showed irregular masses appearing low or slightly low signal intensity on T2WI, and 5 of them invaded the adjacent structures and skull base, which indicating malignant. One adenoid cystic carcinoma showed a small nodule in the superficial lobe with rough margin. One malignant lymphoepithelia lesion was misdiagnosed as adenolymphoma before operation. One basal cell adenocarcinoma showed cystic-solid mass. One peripheral primitive neuroectodermal tumor and one lymphoma showed multiple lesions in right parotid. Conclusion There are some characteristics on MRI of parotid tumors. MRI may make accurate diagnosis before surgery to some extent.