探讨不同病理类型胎儿骶尾部畸胎瘤（SCT）的临床及产前超声声像图特征，分析产前超声在胎儿SCT成熟性鉴别中的作用。

回顾性分析2015年1月至2020年12月在首都医科大学附属北京妇产医院就诊的胎儿SCT病例34例，根据肿瘤不同病理类型将病例分为成熟型和未成熟型，分析不同病理类型组的母体年龄、孕周及肿瘤相关超声特征（生长方式、性质、血流情况）、合并症，并采用χ²检验、Fisher确切概率检验、t检验及Mann-Whitney U检验比较上述资料的组间差异。

根据肿瘤的病理类型分为成熟型组23例和未成熟型组11例。在2组病例中，母体年龄、孕周、胎儿性别、肿瘤生长方式的组间差异均无统计学意义（P均＞0.05）。未成熟型组肿瘤体积明显大于成熟型组［16.19（8.47，34.03）cm³ vs 186.20（90.41，445.35）cm³］，差异具有统计学意义（Z=-3.332，P=0.001）；成熟型组肿瘤以囊性为主（56.5%，13/23），未成熟型组肿瘤均为囊实性（100%，11/11），差异具有统计学意义（P=0.002）。彩色多普勒超声显示成熟型组伴血流信号者有3例，未成熟组则有10例，差异具有统计学意义（P＜0.001）。对肿瘤周围组织以及胎儿其他器官系统扫查发现，成熟型组出现合并症者5例，未成熟型组为7例，组间差异具有统计学意义（P=0.026）。

不同病理类型胎儿SCT的临床特征及产前超声表现不同，产前超声表现为囊实性肿瘤、体积较大、血流信号丰富、合并其他系统异常等是未成熟型SCT的重要鉴别征象，早期诊断可为后续产科管理提供诊疗依据。

To evaluate the clinical and ultrasonic features of fetal sacrococcygeal teratoma (SCT) of different histological types.

A retrospective analysis was performed on a total of 34 patients with SCT that was diagnosed from January 2015 to December 2016 at Beijing Obstetrics and Gynecology Hospital, Capital Medical University. These cases were divided into either a mature group or an immature group based on the histological type. Data (maternal age, gestational weeks, and tumorous sonographic features) were analyzed by the Fisher exact test, t-test, Chi-square, and Mann-Whitney U test.

No statistical differences were observed in terms of maternal age, gestational week, fetal sex, and Altman's classification between the mature (n=23) and immature groups (n=11). Among all the ultrasonic features, mass volume of the immature group was significantly bigger than that of the mature group [16.19 (8.47, 34.03) cm³ vs 186.20 (90.41, 445.35) cm³, Z=-3.332, P=0.001]. The main manifestation of the mature group was cystic echo (56.5%, 13/23), while that of the immature group was cystic-solid echo (100%, 11/11); the difference between the two groups was statistically significant (P=0.002). Color Doppler ultrasound showed that three cases in the mature group and ten cases in the immature group were detected with blood flow signal; the difference in the number of cases with blood flow signal was statistically significant between the two groups (P＜0.001). Scanning of the tissues surrounding the mass and other fetal systems showed that five cases in the mature group and seven cases in the immature group suffered from complications; there was a statistically significant difference between the two groups (P=0.026).

The clinical features and prenatal ultrasonic images of fetal SCT vary with different pathological types. Cystic-solid echogenic masses, bigger mass volume, rich blood flow signals, and suffering from complications are important signs for the diagnosis of immature fetal SCT. Early diagnosis by using prenatal ultrasound can provide a good basis for perinatal management.