Spinnaker-sail sign in full-term neonates with spontaneous pneumomediastinum: a case study and scoping literature review.

BACKGROUND

Pneumomediastinum is a condition that is occasionally observed in preterm neonates, characterized by the presence of free air within the mediastinal spaces. Spontaneous Pneumomediastinum (SPM) in full-term neonates is a rare form. The clinical spectrum ranges from asymptomatic cases to severe respiratory distress.

OBJECTIVE

To highlight the diagnostic challenges posed by the "spinnaker-sail sign", and to create a stepwise framework for clinicians encountering similar cases.

METHODS

We present two cases of SPM in a full-term neonate. Case-1: a 2-day-old boy with respiratory distress exhibited on CXR a crescentic radiolucent configuration elevating the thymus from the pericardium ("spinnaker-sail" sign). CT demonstrated an extrapulmonary multiseptated cystic mass within the anterior mediastinum. The neonate was treated with supplemental oxygen and antibiotics, showing improvement by day 11. Case-2: a 6-hour-old boy presented with respiratory distress shortly after birth. CXR showed the spinnaker-sail sign, alongside a band of air overlying the left hemidiaphragm ("Extrapleural air" sign). Lateral projection revealed mediastinal air collection lifting the thymus from the pericardium and great vessels. He was managed with oxygen moisture and antibiotics, showing significant improvement by day 4.

DISCUSSION

The pathophysiology stems from uneven inflation and minute ruptures of immature alveoli, allowing air to leak through peribronchial and perivascular fasciae into the mediastinum. A fetal-remnant fascia entraps this air behind the thymus, constituting the "spinnaker-sail" appearance. The clinical course is typically benign. The management mainly involves supplemental oxygen and close monitoring. In severe cases, interventions such as needle decompression or chest tube insertion may be warranted.

CONCLUSION

Unfamiliar radiographic patterns of PM in neonates pose diagnostic challenges and interventional hazards. Understanding the unique anatomy of the mediastinum in neonates is essential to formulate a proper diagnosis and management strategy.

CLINICAL TRIAL NUMBER

Not applicable.