Introduction. Acrania is a very rare lethal congenital malformation characterized by an absence of the cranial vault with developed cerebral hemispheres. It is sometimes confused with anencephaly in which both the forebrain and neurocranium are not developed. Although these two conditions principally differ in their morphology and pathogenesis, acrania may be a precursor of the development of anencephaly through the process known as Acrania-exencephaly-anencephaly sequence. Case report. A 27-year-old woman was diagnosed to have a viable fetus with an absent skull vault and uncovered brain directly exposed to amniotic cavity. A diagnosis of acrania was made. A medical abortion was performed in the 14th week of pregnancy. A gross examination of the formalin-fixed fetus revealed a complete absence of the calva and brain tissue. The cranial structures stop abruptly above the orbits and the fetus showed a triangular face with bulging eyes. At the top of the head, a huge defect with a residual thin covering membrane was visible. According to the gross morphology and in correlation with previous ultrasound findings, the pathologist established the diagnosis of secondary anencephaly. Conclusion. This paper suggests that many of the reported anencephaly cases that are diagnosed during the second or third trimester of pregnancy might represent the end of a spectrum that initially appears as isolated acrania. This may be the reason for much higher global incidence of anencephaly compared to acrania.
References
1.
Bianca S, Ingegnosi C, Auditore S, Reale A, Galasso MG, Bartoloni G, et al. Prenatal and postnatal findings of acrania. Archives of Gynecology and Obstetrics. 2005;271(3):257–9.
2.
Li L, Cerda S, Kindelberger D. Isolated acrania in the presence of amnionic band syndrome. A J Med Sci. 2017;10(3):100–2.
3.
Singh A, Goindi AS, Singh G. Acrania-Exencephaly-Anencephaly Sequence on Antenatal Scans. INTERNATIONAL JOURNAL OF ANATOMY RADIOLOGY AND SURGERY.
4.
Gilani SA, Manzoor I. Sonographic Transformation of Acrania to Anencephaly. Donald School Journal of Ultrasound in Obstetrics and Gynecology. 2017;11(3):189–96.
5.
Arias F, Daftary SN, Bhide AG. Practical guide to high-risk pregnancy and delivery: a South Asian perspective. Elsevier India. 2008(64).
6.
Moore L. Anencephaly. Journal of Diagnostic Medical Sonography. 2010;26(6):286–9.
7.
Cafici D, Sepulveda W. First-Trimester Echogenic Amniotic Fluid in the Acrania-Anencephaly Sequence. Journal of Ultrasound in Medicine. 2003;22(10):1075–9.
8.
Gorgal R, Ramalho C, Brandão O, Matias A, Montenegro N. Revisiting Acrania: Same Phenotype, Different Aetiologies. Fetal Diagnosis and Therapy. 2011;29(2):166–70.
9.
Santana EFM, Araujo Júnior E, Tonni G, et al. Acrania-exencephaly-anencephaly sequence phenotypic characterization using two- and three-dimensional ultrasound between 11 and 13 weeks and 6 days of gestation. Journal of Ultrasonography. 2018;18(74):240–6.
10.
Szkodziak P, Krzyżanowski J, Krzyżanowski A, Szkodziak F, Woźniak S, Czuczwar P, et al. The role of the “beret” sign and other markers in ultrasound diagnostic of the acrania–exencephaly–anencephaly sequence stages. Archives of Gynecology and Obstetrics. 2020;302(3):619–28.
The statements, opinions and data contained in the journal are solely those of the individual authors and contributors and not of the publisher and the editor(s). We stay neutral with regard to jurisdictional claims in published maps and institutional affiliations.
