Dermoid Cyst - Types, Diagnosis, and Treatment

Introduction

The term dermoid cyst involves most of the specialties of medicine like dermatology, dermatopathology, general pathology, gynecology, neurosurgery, or pediatrics. All these specialties define dermoid cysts differently. However, as a common factor, dermoid cysts are developmentally entrapped tissues with benign, single, or multiple non-cancerous lesions. Only 40 percent form near the skin surface and are diagnosed at birth; the rest 60 percent develop deep inside the body and are diagnosed by five years of age. The etiology of dermoid cysts is yet to be determined. Dermoid cysts are true hamartomas. However, they occur when the skin and associated structures become trapped during fetal development. Dermoid cysts are the commonest child tumors of the skull. 15% - 58% of all scalp and skull masses in children are dermoid cysts. Females and whites have a higher predisposition.

What Are the Types of Dermoid Cysts?

The classification of a dermoid cyst is based on its location as follows:

Common dermoid cyst types include:

• Ovarian dermoid cyst is present in the ovary.

• Spinal dermoid cyst develops on the spine.

• Periorbital dermoid cyst is present near the outside edge of one of your eyebrows.

Rare locations of dermoid cysts are:

• Epibulbar dermoid cyst present on the surface of the eye.

• Intracranial dermoid cyst is found in the brain.

• Nasal sinus dermoid cyst forms inside the nose.

• Orbital dermoid cyst occurs around the bones of the eye socket.

• Dermoid cyst of the oral cavity seen in the floor of mouth or tongue

Out of ten dermoid cysts present, eight are present on the head and neck.

How Does a Dermoid Cyst Develop?

Dermoid cyst results from abnormal removal and addition of the surface ectoderm along the lines of skin fusion during fetal development. Due to this abnormality, a dermoid cyst can usually be found along skull sutures or the anterior fontanelle. Dermoid cysts are present at birth. During the early development stage in the uterus, the skin layers do not grow together, resulting in a dermoid cyst. A dermoid cyst can form from skin cells, tissues, and glands typically found in skin collected in a sac. These glands continue to produce fluid, often causing the cyst to grow.

What Is the Clinical Presentation of a Dermoid Cyst?

The dermoid cyst presents as any other health condition. The swelling may be pale, skin-colored, or slight blue color, pearly, dome-shaped, firm, deep-seated, small swelling under the skin. Usually seen as an asymptomatic, non-pulsatile, and non-compressible lesion. A dermoid cyst appears as a small swelling under the skin. The skin over the swelling can easily be moved. Most dermoid cysts develop in the head and neck region but can be seen anywhere on the body. The head and neck region is commonly seen in the frontal, neck, and above the eye. When the dermoid cyst is infected, it is seen as hair extending from the tip. Midline dermoid cyst presents as a sebaceous secreting pit that swells and infects alternately.

How Are Dermoid Cysts Diagnosed?

Imaging tests are used to find out the connection between the cyst and other head and neck tissue. These tests include:

1. Physical Examination - If the cyst is present close to the skin’s surface, a complete physical examination of the cyst and the surrounding area is done. A pelvic examination can reveal an ovarian dermoid cyst.

2. X-Ray - Two-dimensional analysis of the location of the cyst in the head, neck, face, or other areas.

3. Computed Tomography (CT) Scan - A computed tomography(CT) scan is a thinly sliced, three-dimensional X-ray using a computer to study detailed images.

4. Magnetic Resonance Imaging (MRI) - Large magnetic field and computer-generated radio waves for detailed images of structures in the body.

5. Pelvic and Transvaginal Ultrasound - Sound waves are used to identify the cyst. A pelvic ultrasound uses a probe, and a transvaginal ultrasound uses a wand.

How Are Dermoid Cysts Treated?

Surgical removal is the only treatment option for a dermoid cyst regardless of its location. Before surgery, there are several key factors to consider, especially if the cyst is treated in a child. These include:

• Medical history.

• Signs and symptoms.

• Risk of any infection present.

• Acceptance for surgery and the post-surgery medications.

• The severity of the cyst.

If surgery is decided, here is what to expect before, during, and after the procedure:

Before Surgery:

• Dermoid cyst removal is done in the outpatient ward or under general anesthesia.
• When done in the outpatient department, the patient is discharged on the same day.
• When surgery is done under general anesthesia, it would be better to have a responsible adult by the side.
• Stop food intake and take medications as directed by the physician.

During Surgery:

• A small incision is made, and the cyst is removed completely.
• The procedure lasts for about 30 minutes.
• When the dermoid cyst is larger, removing the involved organ and the cyst may be required.
• Microsurgical techniques are also used for better and precise removal of the cyst.

After Surgery:

• Any remaining cyst has to be monitored regularly after removing a bigger cyst.
• Recovery after surgery can take up to two or three weeks, depending on the location of the cyst.
• A complete and combined inter-professional approach may require diagnosing and referring patients to concerned specialty will help in better patient satisfaction, quality of life, appropriate care, and decrease the chance of complications.

What Other Lesions Resemble Dermoid Cyst?

Dermoid cysts are a rare developmental anomaly. As it appears nodular, all subcutaneous nodular cyst-like lesions in the head and neck or midline are included in the differential diagnoses.

Following are the differentials of a dermoid cyst:

• Epidermoid cyst.

• Juvenile xanthogranuloma.

• Glioma.

• Encephalocele.

• Lipoma.

• Pilar cysts.

• Meningioma.

• Neurofibroma.

• Teratoma.

• Olfactory neuroblastoma.

• Lymphoma.

• Subcutaneous abscess.

• Facial trauma.

• Rhabdomyosarcoma.

• Trichilemmal cyst.

• Pilomatrixoma.

• Lymphatic malformation.

• Thyroglossal duct cyst.

What Is the Prognosis of a Dermoid Cyst?

The overall prognosis for dermoid cyst patients is good, when

• There is no intracranial or intraspinal involvement.

• It is intracranial or intraspinal involvement with early surgical intervention.

The overall prognosis for dermoid cyst patients is poor, when

• Dermoid cysts turn symptomatic due to local invasion, rupture, and infection.

• Brain compression.

What Are the Complications Seen in Dermoid Cyst?

There are no complications until intracranial or intraspinal layers are involved. Aspirations, biopsies, and when the intracranial or intraspinal are involved can cause infection spread, leading to osteomyelitis, meningitis, or cerebral abscess. Other complications include bony erosions, eyelid displacement, and intracranial extension. Malignant transformation is a rare complication leading to squamous cell carcinoma in sublingual, ovarian, and intra-abdominal dermoid cysts.

Conclusion

A dermoid cyst is a benign developmental anomaly of skin present mainly in the head and neck regions. It is difficult to diagnose these cyst with only clinical examination and conventional radiographs. Hence, special imaging techniques are normally used. As it is a non-cancerous growth, it can be left undisturbed, but early surgical intervention is required when growth is seen. But the surgical excision is greatly influenced by the location of the cyst. A clear understanding of this slow growing mass is necessary to determine its transformation into malignancy.