Subaponeurotic or subgaleal fluid collections in infancy: an unusual but distinct cause of scalp swelling in infancy

Abstract

Subaponeurotic or subgaleal fluid collection is a rare but important cause of scalp swelling in young infants. Fluid in the subaponeurotic or subgaleal space presents as soft, ill-defined, fluctuant, highly mobile scalp swelling and is not limited by suture lines, which makes it clinically very distinct from other scalp swellings. However, the aetiology of such swelling still remains uncertain but may be related to traumatic labour that manifests after the first few weeks of life. There is no indication for imaging if the condition is diagnosed clinically with confidence. The late subaponeurotic or subgaleal fluid collection resolves spontaneously without any intervention, hence conservative management is the treatment of choice.

Figure 1

Skull x-ray showing soft tissue swelling extending from the supraorbital ridge to the nape of the neck (fluid collection in the subaponeurotic plane).

Figure 2

Ultrasound of the cranium showing fluid collection external to the calvarium, confirming the subaponeurotic plane of fluid collection.

Figure 3

MRI (coronal FLAIR sequence). The scalp swelling is seen over the posterior parietal region centrally and extending slightly towards the left. FLAIR sequence was specifically performed to suppress the signal return of CSF and confirmed the collection was of the same signal intensity as the CSF (compared to the fluid in the left ventricle).