颌面颈部表皮样囊肿的超声诊断价值

目的探讨颌面颈部表皮样囊肿的超声特点及诊断价值。方法对51例经病理证实的颌面颈部表皮样囊肿患者的超声声像图特点进行回顾性分析并分型，观察并记录肿块位置、大小、形态、边界、包膜、内部回声及彩色血流信号等。采用Fisher确切概率法对肿块最大径≤10rnm及是否继发感染在各回声类型中所占比例进行比较。结果超声诊断表皮样囊肿的符合率为49．0％（25／51），肿块大多位于皮下（96．1％，49／51），境界清晰（96．1％，49／51），包膜完整（96．1％，49／51），形态多呈椭圆形（65．4％，34／51）。彩色多普勒成像检测到肿块周边有点状血流信号4例，占7．9％（4／51），余47例肿块内部及周边均未检测到血流信号，占92．1％（47／51）。内部回声分为3型：囊性回声伴回声点流动型27例（52．9％，27／51），不均匀回声型15例（29．4％，15／51），均匀类实性回声型9例（17．6％，9／51）。肿块最大径≤10mm与〉10mm、是否继发感染在各回声分型中所占比例的差异均有统计学意义（P=0．038、0．034）。结论颌面颈部表皮样囊肿的典型超声特点为位于皮下、边界清晰、形态椭圆形、内部呈囊性回声伴有回声点流动。均匀类实性回声型中继发感染者及肿块最大径≤10mm者较多，易造成误诊。

Ultrasonographic diagnosis of maxillo-facio-cervical epidermoid cysts

Objective To study the sonogram characteristics of maxillo-facio-cervical epidermoid cysts and the value of ultrasound diagnosis. Methods The sonogram features in 51 cases with pathologically- confirmed epidermoid cysts were analyzed. All the patients were examined by conventional ultrasonography and the location, size, shape, boundary, capsule, internal echo and flow signals of the masses were recorded. Fisher exact test has been used to compare the proportions of mass size smaller than l0 mm and secondary infection among different echo types. Results The accurate rate of ultrasound diagnosis of epidermoid cyst was 49.0% （25/51）. Most epidermoid cysts were located in the subcutaneous layer （96.1%, 49/51）, with clear boundary （96.1%, 49/51）, complete capsule （96.1%, 49/51）, and oval shape （65.4%, 34/5 l）. Color Doppler flow signals were found in the periphery of the masses in 4 cases （7.9%,4/51）, and no color signals around or inside the masses were detected in other 47 cases （92.1%,47/51）. For echotexture, 3 types were found： cystic echogenicity with internal echogenic spots type （52.9%, 27/51）, heterogeneous echogenicity type （29.4%, 15/51）, and homogeneous echogenicity type （17.6%, 9/51）. The proportion of mass size smaller than 10 mm and secondary infection show statistically significant differences among three echo types （P=0.038 and 0.034）. Conclusions The typical ultrasonic features of maxillo-facio-cervical epidermoid cyst are subcutaneous location, clear boundary, oval shape and cystic echogenicity with internal echogenic spots type. The secondary infection and the small mass size are more frequently found in homogeneous type than other types, which may be easily misdiagnosed.