Chronic spontaneous diploic hematoma.

The authors report the case of a 23-year-old woman with café-au-lait spots and axillary and inguinal freckling who presented with a diploic chronic spontaneous hematoma of the left parietal bone. To the authors' knowledge, this case represents the first description of a diploic hematoma in a patient with stigmata of neurofibromatosis Type 1 unrelated to head trauma. Plain skull radiography showed an osteolytic lesion with well-circumscribed margins, corresponding to the hematoma, together with exuberant perilesional vascular markings. Angiography demonstrated an incidental aneurysm of the left supraclinoidal internal carotid artery and an unusual cortical venous drainage toward the diploic vessels. The blood flow of these vessels on the right hemicranium was sluggish and exhibited enlarged diploic venous lacunas. The authors hypothesize that the hematoma was formed by both an abnormal venous drainage toward the diploic vascular net, together with a vasculopathy that caused stenosis and obstruction of the normal drainage pathways from these vessels.