Venous arterialization in extralobar pulmonary sequestration associated with fetal hydrops

Area of Science:

• Perinatology
• Pediatric Surgery
• Pulmonary Medicine

Background:

• Fetal extralobar pulmonary sequestration (EPS) can cause massive pleural effusion (PE), leading to fetal hydrops.
• The mechanisms and fluid origin in EPS-associated PE are not fully understood.
• This study investigated histological hallmarks of EPS with massive PE, hypothesizing venous obstruction's role.

Observation:

• Three cases of fetal EPS with massive PE requiring intervention were analyzed.
• Pleural fluid analysis showed lower protein and cell counts compared to chylothorax.
• Histological examination of EPS-associated PE revealed significantly thickened venous walls (media and adventitia) compared to controls.

Findings:

• Pleural effusion in EPS is characterized as a transudate, distinct from the lymph seen in chylothorax.
• Significantly increased adventitial thickness (9.8% ± 3.8%) and medial thickness (7.0% ± 1.9%) were observed in EPS with PE.
• These findings support the hypothesis of venous obstruction contributing to increased transudate production.

Implications:

• The thickened venous walls in EPS with PE suggest partial venous obstruction as a key mechanism.
• This obstruction likely leads to increased transudate production, resulting in fetal hydrops.
• Understanding these mechanisms is crucial for managing fetal hydrops secondary to EPS.