Spontaneous subaponeurotic fluid collection in an infant: illustrative case.

Background: Spontaneous subaponeurotic fluid collections (SSFCs) are benign, typically self-limiting fluid collections beneath the scalp's aponeurosis. Their abrupt onset and unusual appearance can cause significant alarm and suspicion of considerable pathology or child abuse. With an unclear etiology and concerning clinical presentation, it is important to recognize SSFCs as a unique condition, distinct from those that require immediate neurosurgical intervention.