Trans-scalp dermoid cyst excision and immediate muscle graft: a new technique.

Dermoid cysts are congenital hamartomas probably deriving from anomalous developmental inclusion of embryonic epidermis along embryonic cleft closure lines.1 Their most common sites are the lateral ends of the eyebrows and along the midline in the nasal root; the neck; and the sublingual, sternal, perineal, scrotal, and sacral areas.1 Often seen from as far medially as the mid third of the brow to superolateral to the brow, they are generally asymptomatic and slow growing. They rarely grow larger than a few centimeters but may become as large as 4 cm.2 They are subcutaneous in location; resemble steatocystomas or epidermoid cysts; and usually have sebaceous glandular, rudimentary hair follicle, and sweat gland elements attached to their epithelial linings. At times, even cartilage and bone are present.1 They may in some cases appear to fluctuate in size. Although these cysts may be mobile and extend down to the eyelid, in many cases, they are firmly fixed to the periosteum of the orbital rim, particularly in the area of the frontozygomatic suture. A firm, rounded swelling in the lateral brow in a child is pathognomonic of this lesion. Large cysts may lie in a depression in the bone, split the lateral orbital wall, or extend back into the temporal fossa. Several choices are available regarding the incision sites and surgical methods for cyst removal on the face, including the eyelid crease incision3 and the lid-splitting technique,4 and direct incision on the cyst.5