颌骨造釉细胞瘤各种亚型的CT诊断

CT Diagnosis of Various Subtypes of Ameloblastoma in the Maxillomandibular Region

背景与目的:颌骨造釉细胞瘤根据生物学行为和组织病理学特点可分为多个亚型,其预后各不相同。本研究探讨实性或多囊型造釉细胞瘤(solidormulticysticameloblastoma,SMA)、单囊型造釉细胞瘤(unicysticameloblastoma,UA)和恶性造釉细胞瘤(malignantameloblastoma,MA)的临床和CT影像特点,以提高CT诊断的准确性。方法:收集经病理证实的SMA14例、UA6例和MA5例,对各种亚型的临床和CT表现进行回顾性分析。结果:SMA、UA和MA患者首次就诊时的中位年龄分别为33.5岁、20.5岁和56岁,在CT上的横断面最大径平均值分别为33mm,46mm和59mm。SMA病变中11例(79%)平扫时与肌肉相比呈等低混杂密度,3例(21%)呈较均匀等密度,12例(86%)边缘呈分叶状,13例(93%)骨壳被穿破,6例(43%)形成软组织肿块,但病灶的边界都清楚,10例(71%)见不全骨性分隔,9例(64%)邻近牙根被吸收,11例行增强扫描的病例中9例(82%)呈显著强化。UA病变平扫时与肌肉相比内部都呈均匀低密度,其中4例(67%)呈较规整的圆形或椭圆形,2例(33%)呈分叶状,3例(50%)局部骨皮质有缺损,但未见软组织肿块形成,1例(17%)见不全骨性分隔,2例(33%)邻近牙根有吸收,行增强扫描的3例囊壁均呈轻中度的强化。5例MA的病灶都呈分叶状,且骨皮质均被穿破并有软组织肿块形成,边界不清,其中3例(60%)平扫时与肌肉相比呈等低混杂密度,2例(40%)呈较均匀等密度,3例(60%)可见不全的骨性分隔,3例(60%)见牙根的吸收或破坏,行增强扫描的3例都呈明显强化。结论:SMA多见于中年人,在CT上多表现为强化明显的囊实性肿块,边界清楚;UA常见于年轻人,在CT上表现为囊性肿物,囊壁轻中度强化;MA多见于老年患者,在CT上常显示广泛骨破坏,软组织肿块常见,强化明显,边界不清。综合分析CT征象和临床表现有助于对造釉细胞瘤的上述亚型进行鉴别。

BACKGROUND ＆ OBJECTIVE.. Based on biological behavior and histopathologic characteristics, ameloblastomas in the maxillomandibular region can be divided into several subtypes with different prognosis. This study was to explore the clinical and CT imaging features of solid or multicystic ameloblastoma （SMA）, unicystic ameloblastoma （UA）, and malignant ameloblastoma （MA）, and thus to improve the CT diagnostic accuracy for these diseases. METHODS, Clinical and CT features of 25 histologically proven ameloblastomas in the maxillomandibular region, including 14 SMAs, 6 UAs, and 5 MAs were analyzed retrospectively. RESULTS, The median age of the patients initially diagnosed as SMA, UA, and MA were 33.5, 20.5, and 56 years, respectively. The mean maximal transverse diameters on CT images were 33 mm for SMA, 46 mm for UA, and 59 mm for MA. Of the 14 SMAs, 11 （79%） showed low to intermediate density as compared with muscles, 3 （21%） showed homogenous and intermediate density 12 （86%） appeared as Iobulate lesions 10 （71%） had incomplete bone septa 9 （64%） showed root resorption of the neighboring teeth; 13 （93%） showed cortical perforation; 6 （43%） had soft tissue masses all SMAs showed well-defined margins. Of the 11 SMAs examined by enhanced studies, 9 （82%） showed strong enhancement. CT images of the 6 UAs showed homogenous and low density in comparison with muscles. Of the 6 UAs, 2 （33%） were Iobulate, 4 （67%） were regularly round or oval 1 （17%） had bone septa, 2 （33%） had root resorption of the neighboring teeth, 3 （50%） had cortical perforation. All UAs showed well-circumscribed margins without soft tissue masses. Three UAs were examined by enhanced studies and showed mild to moderate enhancement of the wall. Of the 5 MAs, 3 （60%） showed low to intermediate density as compared with muscles, 2 （40%） showed homogenous and intermediate density 3 （60%） had bone septa; 3 （60%） showed root resorption or destruction of the neighboring teeth. All 5 MAs were lobulate with cortical perforation, soft tissue masses, and illdefined margins. All 3 MAs examined by enhanced studies showed strong enhancement. CONCLUSIONS, SMAs are usually seen in middle-aged patients. CT images of SMAs frequently show Iobulate lesions with strongly enhanced solid and cystic components. UA occurs mostly in young patients, and typically appears as cystic lesion with mild to moderate enhancement of the wall on CT images. MA often appears in old patients, and shows extensive bone destruction, soft tissue mass, ill-defined margin, and strong enhancement on CT images. Combined analysis of CT images and clinical data is helpful in differentiating these 3 subtypes of ameloblastoma.