A 19-week scan shows a large multiloculated septated cystic mass arising from the posterior neck of the fetus, with diffuse subcutaneous oedema and bilateral pleural effusions. Which karyotypic abnormality is most strongly associated?

• A Monosomy X (Turner syndrome) ✓
• B Trisomy 13
• C Trisomy 18
• D Klinefelter syndrome, 47,XXY

Explanation

Septated posterior neck cystic hygromas result from failure of jugular lymphatic-venous connection and are strongly linked to Turner syndrome, particularly when accompanied by hydrops. Trisomy 21 and 18 also show increased NT and occasional hygromas, but the classic septated nuchal hygroma with early hydrops points to monosomy X. Klinefelter syndrome typically escapes prenatal detection and has no characteristic neck finding.

Reference: Callen's Ultrasonography in Obstetrics and Gynecology, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.