Vertex scalp mass as presenting sign of a complex intracranial vascular malformation.

Scalp masses are not infrequently encountered in daily clinical practice. They are represented by a wide spectrum of different clinical entities and are usually managed by an excision or by simple observation. Although it happens rarely, head lumps may hide an underlying cranioencephalic malformation that has to be preoperatively diagnosed to perform an appropriate treatment. Cerebral arteriovenous malformations (AVMs) are not included among the intracranial malformations connected with a scalp mass. The authors report on the unusual case of a child harboring a complex intracranial AVM that initially presented as a small scalp mass. Actually, this young boy came to the authors' attention just for a small, soft, pulsatile, and reducible mass of the vertex that produced a circumscribed bone erosion. The presence of macrocranium and venous engorgement of the face, however, suggested the presence of an intracranial "mass." The neuroimaging investigations pointed out a temporal AVM causing dilation of the intracranial sinuses and ectasia of the vein of the scalp; one of the veins was appreciable as a lump on the vertex.