Abstract :

ABSTRACT 

Background: Congenital cystic swellings involving the floor of the mouth include various lesions such as developmental  cysts (e.g., dermoid and epidermoid cysts), ranulas, vascular malformations etc. However, coexistence of such conditions,  possibly with a cause-and-effect- relationship, is rare. The purpose of this case report is to present a rare case of a congenital  epidermoid cyst associated with a mucous retention cyst in a newborn.

Methods: A 6-month-old female infant was referred to an Oral Medicine Clinic in Athens, Greece on October 2019 for  evaluation of a swelling at the floor of the mouth, first noticed by her paediatrician just after birth. Clinically, a yellowish  “pearly” nodule in close association with the orifice of the left submandibular duct, posteriorly transitioning to a diffuse  bluish cystic swelling of the left floor of the mouth was observed. With a provisional diagnosis of a dermoid cyst and/or  ranula, a surgical excision was performed under general anaesthesia.

Results: Histopathologically, a well-defined, keratin-filled, cystic cavity lined by orthokeratinized stratified squamous  epithelium was observed in the anterior aspect while posteriorly and in close proximity, a dilated salivary duct lined by  cylindrical, cuboidal or pseudostratified epithelium was noted. A final diagnosis of an epidermoid cyst intimately associated  with a mucus retention cyst (ranula) of the submandibular duct was rendered.

Conclusions: The coexistence of two cystic lesions in the floor of the mouth with features of epidermoid and mucous  retentioncyst, respectively, is rare and its pathogenesis intriguing, especially in a newborn.

Keywords: Epidermoid cyst; Mucocele; Newborn; Nonodontogenic cysts; Ranula.