Dermoid Cyst of the Parotid Gland: Case Report of a Rare Entity and Review of the Literature

Abstract

BACKGROUND A dermoid cyst is a benign, epithelial-lined cavitary lesion composed of ectoderm and mesoderm that can arise anywhere in the body, with a tendency to develop in midline structures such as the coccyx and ovary. It is a rare entity in the head and neck region, where the incidence is 7% of all body dermoid cysts. Of these 7% (dermoid cysts found within the head and neck area), 80% are found localized to areas around the orbit, oral region, and nasal region. Within the parotid gland, they are extremely rare, with less than 25 cases reported in the existing literature. CASE REPORT We report a case of a 26-year-old woman with a long-standing left parotid mass that was found to be a dermoid cyst after surgical excision and histological evaluation. We examine the clinical presentation and imaging findings used to establish a presumptive diagnosis to guide treatment options. Although preoperative fine-needle aspiration was not performed in this case, it is often used to clarify the differential diagnosis before definitive surgical management is undertaken. CONCLUSIONS Intraparotid dermoid cysts are rare, benign entities that require complete cystectomy for definitive management. As surgical excision is the only curative method, preoperative histopathological diagnosis via biopsy may be unnecessary. Our paper adds to the existing literature by presenting a case of an intraparotid dermoid cyst successfully treated surgically in a 26-year-old woman.

Figure 1.

CT scan of the head and neck showing a 4.7 cm well-defined, encapsulated, fat-attenuating, and non-enhancing mass within the superficial left parotid gland with some layering debris. No associated nodular enhancing soft-tissue component was observed.

Figure 2.

Gross examination reveals a collapsed cystic structure within the parotid gland with a whitish lining.

Figure 3.

Microscopic examination revealed a benign keratinizing squamous epithelium-lined cyst containing keratinous debris and surrounded by skin adnexal structures, mainly sebaceous glands and some smooth muscle. The cyst was surrounded by purely serous salivary gland acini consistent with parotid gland. The findings are consistent with dermoid cyst of the parotid gland. (125×, H&E). H&E – hematoxylin and eosin stain.