Dermoid Cyst Workup

Updated: Feb 12, 2021
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: Dirk M Elston, MD  more...
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Imaging Studies

Radiography, CT scanning, and MRI are helpful in making the correct differential diagnosis of dermoid cysts. MRI is particularly helpful in diagnosing intracranial or intramedullary dermoid cysts and in assessing the dissemination of fatty masses or droplets. MRI is helpful in planning surgical procedures and in assessing therapeutic success. Three-dimensional reconstructed assessment of a nasal dermoid cyst also may be of value, especially when focusing on the intracranial connection. [23]  An ultrasound algorithm to differentiate thyroglossal duct and dermoid cysts has been proposed. [43]


Histologic Findings

Dermoid cysts are a result of the sequestration of the skin along the lines of embryonic closure. If connected with the ovary, dermoid cysts are true teratomas. Scalp cysts may be evaluated using fine-needle aspiration cytology. [44]

In contrast to epidermal inclusion cysts, dermoid cysts in the skin are lined by an epidermis that possesses various epidermal appendages. As a rule, these appendages are fully mature. Hair follicles containing hairs that project into the lumen of the cyst are often present. The dermis of dermoid cysts usually contains sebaceous glands, eccrine glands, and, in many patients, apocrine glands. Occasionally, the lining epithelium may proliferate as papillary boundaries extend externally or inward toward the lumen of the cyst. This proliferation may have some superficial resemblance to epidermal carcinomatous proliferation, and the growth may be misclassified as a cancer.

Dermoid cysts in the ovary (cystic teratomas) or those disseminated intra-abdominally may contain other structures such as nails, hairs, or cartilage and bone fragments. These cysts have cell walls that are almost identical to those of the skin, and they may contain multiple adnexal skin structures such as hair follicles, sweat glands, and occasionally, hair, teeth, or nerves.

A congenital dermoid together with a bronchogenic cyst of the tongue is extremely rare but has been described in a few patients. [45]