Department of Medical and Surgical Sciences, Obstetric Unit, University of Bologna, Bologna, Italy.
Maternal Infant Department SC, Obstetrics and Gynecology, ASST, Grande Ospedale Metropolitano, Niguarda, Milan, Italy.
Fetal Diagn Ther. 2021;48(6):485-492. doi: 10.1159/000516807. Epub 2021 Jun 28.
The objective of the study was to provide more detailed data about fetal isolated upward rotation of the cerebellar vermis rotation (Blake's pouch cyst) in particular regarding pregnancy outcome.
This is a retrospective study of all cases of fetal isolated upward rotation of the cerebellar vermis (URCV) diagnosed in 3 referral centers in Italy from January 2009 to November 2019. Whenever possible, prenatal magnetic resonance imaging (MRI) was performed and a fetal karyotype was obtained. A detailed follow-up was obtained by consultation of medical records, interview with the parents, and the pediatricians.
Our study population included 111 patients with a prenatal diagnosis of isolated URCV made at a median gestational age of 21 weeks +3 days (interquartile range (IQR) 21 + 0-22 + 2). The median brain stem-vermis (BV) angle was 27° (IQR 24-29°). In 37.9% of the cases, a regression of the finding with restoration of normal anatomy was noted at a follow-up scan or at postnatal checks. A BV angle of 25° or less predicted regression with a probability in excess of 90%. MRI was performed in utero or at birth in 101 patients and always confirmed sonographic diagnosis. Fetal CGH array and/or karyotype was available in 97 cases and was always normal, but in 1 case. A postnatal follow-up was available in 102 infants (mean 7 months, range 0-10 years of age) and documented a normal neurologic development in all the cases.
Isolated URCV is most likely a normal variant of fetal anatomy without clinical consequences, at least at an early follow-up. A BV angle of 25° or less predicts intrauterine regression of the finding, but the outcome is good in all the cases. When a confident sonographic diagnosis is made, MRI is not mandatory. The risk of a chromosomal anomaly in these cases is probably low.
本研究的目的是提供关于胎儿孤立性小脑蚓部向上旋转（Blake 袋囊肿）的更详细数据，特别是关于妊娠结局。
这是一项回顾性研究，纳入了 2009 年 1 月至 2019 年 11 月在意大利 3 家转诊中心诊断为胎儿孤立性小脑蚓部向上旋转（URCV）的所有病例。只要有可能，就进行产前磁共振成像（MRI）检查并获取胎儿染色体核型。通过查阅病历、与家长面谈和儿科医生咨询获得详细的随访结果。
本研究人群包括 111 例产前诊断为孤立性 URCV 的患者，中位孕龄为 21 周+3 天（四分位距（IQR）21+0-22+2）。中位脑桥-蚓部（BV）角为 27°（IQR 24-29°）。在 37.9%的病例中，在随访扫描或产后检查时发现该表现消退并恢复正常解剖结构。BV 角为 25°或更小预测消退的概率超过 90%。101 例患者在宫内或出生时进行了 MRI 检查，且始终与超声诊断一致。97 例患者进行了胎儿 CGH 微阵列和/或染色体核型检查，结果均正常，但 1 例异常。102 例婴儿（平均 7 个月，范围 0-10 岁）获得了产后随访，所有病例的神经发育均正常。
孤立性 URCV 很可能是胎儿解剖的正常变异，至少在早期随访中没有临床后果。BV 角为 25°或更小预测该发现的宫内消退，但所有病例的结局均良好。当做出明确的超声诊断时，MRI 并非必需。在这些病例中，染色体异常的风险可能较低。
