颌下腺多形性腺瘤增强CT特点与病理对照分析

摘要

目的:探讨颌下腺多形性腺瘤(PAS)增强CT的影像学表现特征,结合病理结果进行对照分析,提高对该区域此种类型肿瘤的影像诊断水平.方法:回顾性分析经手术及病理证实的22例PAS患者的临床表现及128排双期增强CT影像学表现特征,对肿瘤发生部位、数目、大小、形态、边界、CT密度、强化特点及CT值量化指标等方面进行综合分析.结果:22例颌下腺PAS病例中,左侧9例,右侧13例;位于颌下腺浅部者17例,跨浅、深部者2例,位于深部者3例;21例为单侧单发,1例为右侧多发.肿瘤最大截面横径为1.0～4.7 cm,平均约为2.3 cm;大多呈类圆形、椭圆形软组织肿块,边界清晰.CT平扫密度多不均匀,肿块密度较均匀6例(6/22),不均匀16例(16/22)(16例可见大小不一的低密度囊变区,其中3例内可见点状或斑片状钙化灶).肿块实质部分呈等密度16例(16/22),稍低密度6例(6/22)(与同层咬肌密度相比较).所有肿瘤动脉期CT值约为(59.9±12.6)HU,静脉期病灶实性部分仍继续强化,CT值约为(71.1±13.5)HU.经统计分析,所有PAS中2例(2/22)病灶无强化,17例(17/22)病灶呈轻-中度强化,3例(3/22)病灶呈明显强化.所以,PAS的增强模式为:肿块实质部分大部分呈轻中度的渐进性强化.结论:PAS是颌下腺最为常见的良性肿瘤,多见于40岁以上的女性,常单侧发病,多位于颌下腺后下部的边缘带,大多呈类圆形软组织肿块影,边缘清晰,平扫密度多样,内部可见囊变坏死及钙化区域,增强后肿瘤包膜显示清楚,肿瘤血供不丰富,大部分肿瘤实质部分呈轻至中度的渐进性强化,具有一定的增强CT影像学表现特征,结合患者病史,临床表现,有助于提高该区域此类型肿瘤的诊断率.%Objective To explore enhanced CT findings of pleomorphic adenoma in submandibular gland (PAS) and compare those findings with pathologic results for improving the diagnostic accuracy of enhanced CT image for PSA.Methods The clinical manifestations and enhanced dual-phase CT findings of 22 patients with surgically and pathologically confirmed PAS were analyzed retrospectively.The location,number,size,morphology,border,CT density,enhancement pattern and CT quantitative diagnostic index were comprehensively analyzed.Results Among the 22 selected cases,left PAS was found in 9 cases and right PAS in 13 cases;17 cases located in the superficial lobe of submandibular gland,3 cases in the deep lobe of submandibular gland,and 2 cases involved both superficial and deep lobes;only 1 case was unilateral and multiple,and the others were unilateral and solitary.The maximum transverse diameter of tumor was 1.0-4.7 cm,with a mean diameter at 2.3 cm.The lesions were mostly round-like or oval soft tissue mass with clear boundary.The CT plain scan density were homogeneous in 6 cases (6/22) and heterogeneous in the others (16/22) where hypodensity cystic masses of different sizes were found,and among them,punctate or patchy calcifications were found in 3 cases.The solid components of 16 cases (16/22) were isodensity,and the other 6 cases (6/22) were mild hypodensity,compared with the density of masseter at the same layer.On arterial phase images,the CT value was about (59.9±12.6) HU and on venous phase image,the solid components kept enhanced and the CT value was about (71.1± 13.5) HU.The statistical analysis showed that no enhancement in 2 cases (2/22),mild to moderate enhancement in 17 cases (17/ 22),and remarkable enhancement in 3 cases (3/22),which indicated that most of solid components of PAS were progressively enhanced (mild to moderate).Conclusion PAS is the most common benign tumor at submandibular gland,mostly occurred in females aged over 40 years old,and often only involved the lower boundary part of submandibular gland.In most cases,the lesions were presented as round-like soft tissue mass with clear boundary.The CT plain scan showed various densities,and some cystic necrosis and calcification in the interior of tumor.After enhancement,the tumor appears some CT enhancement features,such as clear tumor capsule,no abundant blood supply to the tumor,and progressively enhancement (mild to moderate) in most of the solid components of tumor.The comprehensive consideration of the medical history and clinical manifestations is helpful for improving the diagnostic accuracy of PAS.