Dermoid tumors are inclusion cysts, which mean they are formed by the implantation of epithelial tissue into another structure. They most frequently occur on the face, inside the skull, on the lower back, and in the ovaries. More rarely they can arise in the brain, nasal sinuses, and spinal cord.
Dermoid cysts are bizarre in that they contain developmentally mature skin, complete with hair follicles and sweat glands, sometimes luxuriant clumps of long hair, and often pockets of sebum, blood, fat, bone, nails, teeth, cartilage, and thyroid tissue. Because they contain mature tissue, these cysts are almost always benign. Usually solitary, they expand slowly over many years due to the central accumulation of epithelial debris and glandular secretions. These cysts are not tender unless they rupture.
Epidermoid tumors are similar in structure and origin to dermoids and the two are often grouped together. Epidermoids are lined with stratified squamous epithelium (skin) as dermoids are, but do not contain the additional skin appendages. Epidermoid cysts are less likely to rupture.
Symptoms are associated with the location of the tumor and the effect of its mass on adjacent tissues. The symptoms can include pain and vision problems.
Several minimally invasive treatments are available at UPMC, offering benefits such as minimal scarring, fewer side effects and complications, and faster recovery. These include the Endoscopic Endonasal Approach (EEA) to reach tumors at the base of the skull and upper spine, and Neuroendoport® Surgery to reach tumors within the substance of the brain (the parenchyma) or within the fluid spaces of the brain (the ventricles). If complementary treatments, such as radiation therapy, are needed, those therapies can begin soon after EEA surgery.
Your doctor will perform a physical exam and ask you about any symptoms you are experiencing. Symptoms depend on the tumor's location and whether the tumor is intact or has ruptured.
- Suprasellar (above the base of the skull) tumors can cause vision problems from compression of the optic chiasm. Disruption of pituitary function also may occur and result in a hormonal imbalance. Seizures may result from tumors that extend to the temporal lobe and lateral sulcus (Sylvian fissure).
- Intraventricular dermoid tumors most frequently are located in the fourth ventricle, whereas intraventricular epidermoids can occur in any ventricle. Both can cause hydrocephalus, which is excessive accumulation of cerebrospinal fluid in the ventricles of the brain that results in enlargement of the head as well as many neurologic complications.
- Dermoid/epidermoid tumors in the spinal canal may cause back or leg pain.
Imaging studies, such as MRI or CT scans, will help the doctor to locate the cyst. An MRI scan can find intracranial or intramedullary dermoid cysts better because it can better depict the location and involvement of other structures. MRIs also are more sensitive in determining if the cyst has ruptured.
Surgery
Dermoid and epidermoid tumors of the skull base may be approached directly by using the Endoscopic Endonasal Approach (EEA). This approach allows surgeons to see the tumor well without making incisions in the face or skull. The tumor is removed through the nose and nasal cavities, and recovery time is faster than with the traditional approach.
Neuroendoport® Surgery offers a minimally invasive option for deep-seated tumors within the substance of the brain or within the ventricles (fluid spaces). A narrow tube or port allows doctors to access tumors such as gliomas or brain metastases through a tiny incision in the skull, in contrast to conventional brain surgery.
At UPMC, we take a 360° Approach to treatment when evaluating each patient—looking at their conditions from every direction—to find the path that is least disruptive to the patient's brain, critical nerves, and ability to return to normal functioning. Our neurosurgical team may recommend a combination of surgical approaches to maximize the benefits of surgery while minimizing risks.
During surgery, extreme care is taken to prevent the fatty content of the cyst from spreading to the surrounding tissues or anatomic structures, especially if the cyst is infected with bacteria. The spread of these contents can cause foreign body reactions and severe complications.
