Dermoid Cyst of Submental Region Mimicking Pilomatricoma

Abstract

Diagnosis of midline neck swellings may give a myriad of options, ranging from ranula, thyroglossal duct cyst, cystic hygroma, cystic lymphangioma, epidermoid, dermoid and teratoid cysts to benign or malignant neoplasms of the mucosa or salivary glands and also rare skin appendage tumours like pilomatricoma or pilomatrix carcinoma. Various pitfalls are encountered in diagnosing these midline swellings as most of the features are overlapping. Careful history and examination have to be complemented with other diagnostic aids such as conventional radiography, ultrasonography, aspiration cytology and computed tomography to arrive at a correct diagnosis. Dermoid cysts in the head and neck are relatively uncommon, present in the midline either above or below the mylohyoid muscle thus differentiating it into sublingual and submental dermoids and can grow to a massive size before presenting symptoms if it breaches the mylohyoid muscle. Pilomatricoma is a skin appendage tumour which presents as midline swelling and is usually diagnosed with careful history and certain pathagnomonic features on fine needle aspiration cytology and ultrasonography. Hereby we are presenting a case of a submental swelling which was diagnosed as a dermoid cyst upon excision but which initially posed a diagnostic challenge because of features of pilomatricoma seen on FNAC.

A case of a sublingual dermoid cyst in a 6‐year‐old child

“…Jourdalin first reported dermoid cysts as sublingual dermoids . Dermoid cysts arise commonly in the skin as well as intracranially and in the spine and ovary .…”

“…CT and MRI scans provide reliable assessments of the lesion extension into deeper structures when diagnosing and evaluating the submandibular space. CT aids the surgeon in establishing a more efficient treatment plan and enables visualization of the relationship of the lesion with muscles, salivary glands, and other tissues . MRI allows for a more precise localization of the lesion in relation to the geniohyoid and mylohyoid muscles .…”

“…Surgical excision of the cyst is the only effective treatment, which is facilitated by the presence of a capsule, and the approach remains dictated logically by the lesion location . Although complications are unusual, dermoid cysts of the oral floor can become infected, with formation of a sinus and intraoral or cutaneous fistulas.…”

“…According to the classification described in the literature, histologically they are divided into three groups: dermoid, epidermoid, and teratoid cysts. Dermoid cysts are lined by epidermis with the presence of adnexae such as sweat glands, sebaceous glands, hair, and hair follicles . Epidermoid cysts are lined with simple squamous epithelium with a fibrous wall and no adnexal structures .…”

Management of a Giant Sublingual Dermoid: A Case Report

“…Patients usually present with dysphagia, dysphonia, and dyspnea. The cysts in the midline are mainly due to entrapment of ectodermal tissues of first (mandibular) and second (Hyoid) branchial arches, known as dysdontogenic hypothesis or due to traumatic implantation of epithelial cells into deepertissues which suggests traumatic cause [5].…”