Report of eight cases of occipital dermal sinus: an update, and MRI findings.

Abstract

We report our experience with 8 patients who were ultimately diagnosed as having occipital dermal sinuses. Clinical presentation, imaging findings and outcome are discussed, along with a review of the literature. In eight patients with occipital dermal sinuses, we retrospectively collected the following data: time to diagnosis, presenting signs, dermal anomalies, location of bone defects, intraparenchymal extension, surgical techniques and clinical outcome. Conventional radiography was performed in all patients; computerized tomography (CT) scans and magnetic resonance imaging (MRI) in all but two. Time to diagnosis ranged from 3 months to 9 years. Presenting symptoms were: infection of a cutaneous mass (n = 4), occipital mass (n = 2), intracranial hypertension related to intra-cerebral abscess (n = 2). In all patients, dermal sinus was located near the external protuberance of the occipital bone. In all patients but one, a cutaneous orifice was associated. Other cutaneous anomalies were: hairy nevus (n = 2) and subcutaneous cysts (n = 4). One patient had associated cranio-facial malformations. Plain skull films revealed linear bony defects in all cases but one; CT scans revealed linear bony defects in all cases, osteitis and intra-parenchymal abscesses if present but they did not allow the delineation of the sinus tract. MRI performed in six patients allowed a better appreciation of the malformation revealing intracranial abscess (n = 1), the sinus tract (n = 2), inclusion cysts (n = 2), and associated venous anomalies (n = 1). Surgery was performed in all patients: a complete removal of the dermal sinus was obtained in all patients but one; inclusion cysts were found in six patients. Total recovery without sequelae was obtained in all patients, except one who suffered from developmental delay and a polymalformative syndrome. In newborns, a meticulous visual exploration of the midline skin along the craniospinal axis is necessary to detect congenital dermal abnormalities. Early surgery is required to prevent severe intracranial infection. MRI could help to determine the surgical approach by delineation of the sinus tract, its extension into deeper tissues and its association with cysts, abscesses or venous anomalies.