Dermoid cysts are sacs or growths that contain fluid or semisolid material. They may contain solid tissues such as skin, hair, and sweat glands. In children, they often present on the face. The three main facial anatomic locations are the brow (or frontotemporal), orbit, or nasal and forehead midline. These are considered a congenital abnormality, with the problem occurring during fetal development. These are considered benign (non-cancerous) lesions.
They are thought to form during development of the cranial bones when the embryonic ectoderm is pinched off as the cranial sutures close. The cyst grows when components such as skin, hair, and sweat glands inside the cyst continue to produce their normal substances.
Depending on the location of the cyst, there is a small risk of extension of the cyst inside the skull with attachment to the brain (intracranially). These most often are in the middle of the face between the eyes or on the nose. Based on this risk, an ultrasound, CT scan, or MRI may be ordered to obtain more information and characterization of the cyst. The cyst will continue to grow over time, and is at risk for infection. Treatment of the cyst involves surgically removing the entire cyst and any underlying extension. Aspirating or draining the cyst with a needle will not be effective because the cyst lining needs to be removed in order to prevent it from growing back. The vast majority of cysts can be removed as an outpatient day surgery procedure through an incision on the skin. For the rare cysts that extend intracranially, a combined approach with a neurosurgeon is needed to remove the cyst, its deep extensions through the bone, and attachments to the brain.