Hair collar sign around hemangioma.

Abstract

The collar sign is usually considered expression of a dysraphic condition similar to what happens in the lumbosacral region (2). In the parietal or occipital region, usually on the midline, but sometimes laterally you can see a greyish plaque, devoid of hair, of soft consistency, surrounded by a circle of darker, thicker and longer hairs and often located at the center of a salmon-patch (Fig. 2). The magnetic resonance reveals level with the plaque the presence of tissue isodense to that meningeal and/or encephalic, sometimes communicating through a cleft of the bone with intracranial meningeal and nervous tissue. However, the hair collar sign can be found also around a lesion of aplasia cutis (1) or sebaceous nevus (3). Ours is the first case in the literature of a hair collar sign around hemangioma.