Hypoechoic liver in fetuses with trisomy 21

Area of Science:

• Prenatal diagnosis
• Fetal medicine
• Genetics

Background:

• Transient abnormal myelopoiesis (TAM) associated with hypoechoic hepatomegaly has been previously observed in fetuses with trisomy 21 (T21).
• Existing literature primarily links these findings to the third trimester.

Observation:

• A series of three cases of T21 fetuses presenting with hypoechoic liver (HL) in the second trimester is described.
• These cases showed no evidence of TAM on hematological or histological examination.

Findings:

• Hypoechoic liver (HL) in the second trimester may be an independent indicator of trisomy 21 (T21).
• The observed hypo-echogenicity is postulated to result from liver congestion due to hemodynamic disturbances common in T21 fetuses.
• One case of T21 was identified solely through the isolated finding of HL, despite negative first-trimester screening.

Implications:

• Hypoechoic liver (HL) may serve as an early prenatal sonographic marker for trisomy 21 (T21).
• This finding could aid in the detection of T21 in cases with negative first-trimester screening.
• Further research with larger cohorts is needed to confirm the association between isolated second-trimester HL and T21.