Cecilia Be

Pseudocyst of the umbilical cord: prenatal sonographic appearance and clinical significance

OBJECTIVE To assess the clinical significance of umbilical cord pseudocysts detected prenatally by sonography. METHODS The prenatal sonographic findings, karyotype, and perinatal outcome in 13 fetuses with umbilical cord pseudocysts were reviewed retrospectively. RESULTS Umbilical cord pseudocysts were diagnosed at a median gestation of 27 weeks (range 15-37). Pseudocysts were single in eight cases with cyst diameters ranging from 20 to 50 mm, and double in one case. In the remaining four cases, multiple small cystic masses measuring less than 8 mm were identified. Additional sonographic findings were noted in 11 cases; ten of these fetuses had prenatal karyotyping, which showed trisomy 18 in five cases, trisomy 13 in one case, and a 46,XX, inv ins(18;21) complement in one case. Among the seven chromosomally abnormal fetuses, umbilical cord pseudocysts were multiple in four fetuses and single in three. All chromosomally abnormal fetuses and two euploid fetuses with associated structural defects died in utero or in the neonatal period. There were no perinatal complications in either of the fetuses with isolated pseudocysts. CONCLUSION The prenatal sonographic appearance of umbilical cord pseudocysts varied widely. These umbilical cord cystic masses were associated strongly with chromosomal disorders and structural defects, regardless of their sonographic appearance in utero.

Holoprosencephaly at 9 Weeks 6 Days in a Triploid Fetus Two- and 3-Dimensional Sonographic Findings

Received October 29, 2006, from the Fetal Medicine Center (W.S., I.L.), Department of Obstetrics and Gynecology, and Cytogenetics Laboratory (C.B.), Clinica Las Condes, Santiago, Chile. Manuscript accepted for publication November 2, 2006. We thank Filiberto Guerra, MD, for performing the postmortem examination and Medison Co, Ltd (Seoul, Korea) for an equipment loan. This work was supported by Sociedad Profesional de Medicina Fetal “Fetalmed” Limitada, Chile. Address correspondence to Waldo Sepulveda, MD, Fetal Medicine Center, Clinica Las Condes, Casilla 208, Santiago 20, Chile. E-mail: fetalmed@yahoo.com Abbreviations 3D, 3-dimensional oloprosencephaly is a rare intracranial abnormality arising from failure of the prosencephalon to cleave during early embryonic life, which results in different degrees of lateral ventricular fusion and facial defects.1 This condition is classified according to brain structures into lobar, semilobar, and alobar, the latter being the most severe form.1 In this report, we describe one of the earliest prenatally diagnosed cases of holoprosencephaly, in which 3-dimensional (3D) imaging was used to assist in the diagnosis. A 27-year-old woman, gravida 4, para 2, spontaneous aborta 1, was referred at the menstrual age of 9 weeks 6 days for sonographic evaluation because of a suspected fetal brain anomaly detected at the dating scan. Her medical and obstetric histories were unremarkable, and the current pregnancy was otherwise uncomplicated. Transvaginal sonographic evaluation at referral revealed a live singleton fetus with a crown-rump length of 34 mm and a large anechoic area behind the forehead (Figure 1). With the assistance of 3D eXtended Imaging technology (Accuvix XQ; Medison Co, Ltd, Seoul, Korea), including Multislice View and Volume CT, multiple sections of the fetal brain were obtained, which helped in selecting the best plane to show the single ventricular cavity and fused thalami (Figure 2). A follow-up scan 1 week later revealed a 45-mm live fetus with alobar holoprosencephaly, midfacial hypoplasia, small orbits, a suspected small omphalocele, and an increased nuchal translucency thickness of 5.6 mm (Figure 3). The placenta appearance was normal. Trophoblast culture obtained from chorionic villus sampling revealed a 69,XXY karyotype. The patient miscarried at 13 weeks. Pathologic examination of the fetus and placenta confirmed the prenatal diagnosis (Figure 4).

Pure XX gonadal dysgenesis in identical twins

Pure gonadal dysgenesis has been described in several sibships. We report a pair of monozygous twins and their younger sister with secondary amenorrhea. They had no associated congenital anomalies. Plasma FSH levels were elevated and the ovarian biopsies showed absence of follicular structures. Their karyotypes were 46XX, further supporting the concept that this form of familial gonadal dysgenesis is an autosomal recessive defect.

Prenatal Diagnosis of Double Trisomy 48,XXX,+18 in the First Trimester

Double trisomy is a relatively common event in pregnancies ending in early miscarriage and usually involves at least 1 nonviable aneuploidy. 1 However, cases that continue beyond the first trimester of pregnancy are exceptionally rare. Among these cases, double trisomies usually involve the sex chromosomes in combination with potentially viable autosomal trisomies such as 21, 18, and 13. 2 In this report, we present a case of double trisomy 48,XXX,+18 diagnosed in the first trimester of pregnancy as the result of nuchal translucency screening for Down syndrome.

Accuracy of the haemoglobin alkaline denaturation test for detecting maternal blood contamination of fetal blood samples for prenatal karyotyping

The haemoglobin alkaline denaturation test was routinely performed in 183 fetal blood samples obtained by cordocentesis for prenatal karyotyping by adding 0.1 ml of the blood into a glass test tube containing 5 ml of water and 0.3 ml of 10 per cent KOH as the alkali reagent. The mixture was agitated gently and read at 2 minutes, at which time it was interpreted as a pure fetal blood sample or contaminated with maternal blood according to the change in colour. In order to determine the accuracy of this test to detect maternal blood contamination, the results were compared with the number of fetal and maternal cells detected by standard cytogenetic techniques in those blood samples obtained from male fetuses (n=97). Among these samples, the haemoglobin alkaline denaturation test gave an adult haemoglobin reaction in two cases (2.1 per cent); both samples showed different degrees of maternal 46,XX cells in the metaphases examined (29 of 30 cells in one case and 2 of 31 cells in the other). Conversely, of the 95 samples which gave a fetal haemoglobin reaction, the cytogenetic analysis did not reveal any maternal cells in the metaphases analysed (median 30 cells, range 20–65). We concluded that the haemoglobin alkaline denaturation test is an accurate method for excluding clinically significant maternal blood contamination of fetal blood samples obtained for prenatal karyotyping. This simple, inexpensive technique provides immediate information and, therefore, can be safely incorporated as a bedside test for analysis during fetal blood sampling procedures. Copyright

Partial trisomy 20q in a fetus with hypoplastic nasal bone, mild ventriculomegaly, and short femur.

Partial duplication of the long arm of chromosome 20, also known as partial trisomy 20q , is a rare condition characterized by a variety of nonspecific craniofacial, cardiac, and skeletal defects in association with different degrees of neurodevelopmental delay (Blanc et al., 2008). The diagnosis is often elusive, with most reported cases being detected in children with noncharacteristic structural and functional anomalies prompting cytogenetic analysis (Pawlowitzki et al., 1979; Sax et al., 1986; Pierquin et al., 1988; Herens et al., 1990; Waters et al., 1990; Addor et al., 2002; Grange et al., 2005; Wanderley et al., 2005; Iglesias et al., 2006; Blanc et al., 2008). To our knowledge, based on a Medline database search, the prenatal detection of this condition has not been reported previously. We describe a case of de novo partial trisomy 20q diagnosed by amniocentesis after the sonographic detection of subtle fetal anomalies in the second trimester. A 32-year-old-woman, gravida 2, para 1, presented at 27 weeks of gestation for a sonographic evaluation after the detection of minor sonographic markers of aneuploidy during the detailed second-trimester scan. There was no previous history of genetic disorders or consanguinity, and her previous pregnancy from another partner resulted in a healthy infant delivered spontaneously at term. A first-trimester sonogram at 7 1/2 weeks confirmed the dates, but no first-trimester scan for nuchal translucency thickness measurement was performed. The detailed second-trimester scan at 23 weeks had shown a male fetus with femur length below the fifth percentile for gestational age and the suspicion of a small perimembranous ventricular septal defect. At referral, a short femur, mild ventriculomegaly of 12 mm, and a hypoplastic nasal bone of 2.7 mm were demonstrated (Figure 1a). This constellation of findings was highly suspicious of trisomy 21, but a three-dimensional (3-D) sonographic evaluation of the fetal face (Accuvix XQ, Medison Co., Seoul, Korea) revealed no facial dysmorphism suggestive of

Pure XX Gonadal Dysgenesis in Identical Twins

Pure gonadal dysgenesis has been described in several sibships. We report a pair of monozygous twins and their younger sister with secondary amenorrhea. They had no associated congenital anomalies. Plasma FSH levels were elevated and the ovarian biopsies showed absence of follicular structures. Their karyotypes were 46XX, further supporting the concept that his form of familial gonadal dysgenesis is an autosomal recessive defect.