Basílio de Almeida Milani

Congenital teratoid cyst of the floor of the mouth

The teratoid cyst, a very rare developmental pathosis, is a type of dermoid cyst that probably arises from ectodermal differentiation of multipotential cells along the lines of embryonic fusion points. We report a rare case of a congenital teratoid cyst of the floor of the mouth in a pediatric patient and discuss the surgical treatment and pathological features of this lesion. A newborn male was referred for evaluation with difficulty in feeding caused by a sublingual swelling. Clinical examination revealed a 2.0 cm symptomless, firm, nodular mass in the sublingual region with well-defined borders, a smooth surface, and covered by normal mucosa (Fig 1A). No lymphadenopathy was present. The radiographic examination showed a slightly diffuse, radiodense, well-defined image localized in the floor of the mouth (Fig 1B). The lesion was fast growing, doubling in size in 2 days, and pushing the tongue against the palate. The aspiration revealed a greenish, creamy material interpreted as saliva. An incisional biopsy was performed in the fourth day of life, and the specimen was sent to the Oral Pathology Department, University of São Paulo for histologic examination with the clinical hypothesis of dermoid cyst. On microscopic examination, the lesion showed a thick cystic capsule that contained derivatives of ectoderm, mesoderm, and endoderm. Ectoderm was represented by keratinized stratified squamous epithelium, positive for cytokeratin (Ck) 14 and skin appendages represented by sebaceous