A dermoid cyst is a congenital benign lesion that often occurs at the level of the lateral eyebrow or in the midline, right above the nose. It is a congenital cyst, meaning that the baby is born with it. Sometimes, it is hard to notice at birth, but it becomes more noticeable over the first few months of life.
A dermoid cyst is filled with specialized cells that remain trapped under the skin during fetal development. Those cells are supposed to be outside the skin and include sweat gland cells, hair follicle cells and skin cells. The contents have often a whitish/yellowish color.
Unlike what it may appear. Those cysts are not under the skin, they are actually quite deep, under skin, muscle and periosteum (which is a layer right on top of bone). So those cyst grow right on top of bone and can cause a bony deformity (that resolves completely once you remove the cyst).
Since those cysts grow deep, people sometimes do not appreciate how large they are. They keep growing over time, they do not go away and they cannot be treated with a needle aspiration. The treatment is surgical because it is imperative to remove the entire cyst with its wall to prevent any recurrence.
It is important to have the procedure done by a pediatric plastic surgeon who is familiar with the pathology. Since it is an elective procedure, i like to excise them after 6 months of age (i like to wait for the baby to grow well and anesthesia is extremely safe after 6 months of age). I would recommend to not delay the excision since they keep growing and thus any delay will require a longer incision for removal and the bony deformity worsens with time (although it resolves most of the time). Find attached a picture of a dermoid cyst that was excised. Looks like a white bean.
youssef tahiri md