促结缔组织增生型成釉细胞瘤的CT影像特点

目的 回顾性分析促结缔组织型成釉细胞瘤(desmoplastic ameloblastoma,DA)的临床和影像学特点。方法 回顾2000年7月至2017年8月北京大学口腔医院诊治的颌骨成釉细胞瘤病例,分析各类型成釉细胞瘤的构成比和一般特征。选取具有完整病历和影像资料的DA病例28例、实性多囊型和单囊型成釉细胞瘤连续病例各50例进行对比分析,提取关键影像特征,包括边界、周围骨质、三维形态、内部结构、牙和牙周膜情况、密质骨等,并比较病变的CT值。结果 1 269例颌骨成釉细胞瘤中DA构成比为3.9%,上颌发病率达46.0%,好发于前牙区(62.0%)和前磨牙区(30.0%)。DA在CT中多表现为边界呈扇贝样,内部含有骨化结构的实性肿物。肿瘤平均高度与长轴径比值为0.76,平均颊舌径与长轴径比值为0.63,大于其他两类成釉细胞瘤。根据成骨密度特点,DA可见3种类型:成骨致密型(Ⅰ型)、蜂窝/皂泡型(Ⅱ型)和成骨稀疏型(Ⅲ型);Ⅰ~Ⅲ型CT值分别为:(488.8±164.0) HU、(171.7±102.8) HU和(42.1±8.8) HU,均高于其他两种类型成釉细胞瘤。结论 DA在CT中表现为内部含不同程度骨化的实性病变,对于影像鉴别诊断具有一定的临床意义。

Computed tomographic features of desmoplastic ameloblastoma of the jaw

Objective: To retrospectively analyze the clinical and CT imaging features of desmoplastic ameloblastomas (DA) in comparison with other types of ameloblastomas.Methods: Patients diagnosed with ameloblastoma histopathologically in Peking University School and Hospital of Stomatology from July 2000 to August 2017 were reviewed to analyze the constituent ratios and characteristics of DA. CT imaging features of DA (28 cases) were investigated in comparison with consecutive cases of solid/multicystic and unicystic ameloblastomas. The following imaging perspectives were analyzed: the border, internal structure, three-dimensional shape, tooth, the periodontium, the cortex and the expansion of the tumors. CT values were measured in the region of interest for quantitative analysis.Results: Among the 1 269 cases of ameloblastomas, 50 (3.9%) were DA,which showed predilections for males (74.0%). The average age of DA was about 43.9 years old, which was higher than the other two types. The anterior incisor-canine region (62.0%) and premolar region (30.0%) were most frequently affected. The incidence rate of DA in mandibule was 56.0% (28/50), which was slightly higher than that of maxilla (44.0%). The DA characteristically showed scallop border and honeycomb-like or soap-bubble internal structure with bone formation on CT. The mean ratios of height to mesio-distal and buccal-lingual to mesio-distal distances were 0.76 and 0.63, which were higher than the other two types. According to the degree of internal bone formation, three subtypes of DA could be observed: densely ossifying type (Ⅰ), honeycomb/soap bubble type (Ⅱ) and sparsely ossifying type (Ⅲ). The means and standard deviations of CT values of DA were significantly higher than those of the other two types, which were (488.8±164.0) HU (type Ⅰ), (171.7±102.8) HU (type Ⅱ), (42.1±8.8) HU (type Ⅲ).Conclusion: CT is helpful for diagnosis of DA, which shows as solid tumor with varying degrees of internal ossification.