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.