A case of an epidermoid cyst of the tongue containing a wood chip in the cystic cavity

We report an epidermoid cyst of the tongue which contained a wood chip in the cystic cavity. The patient, a 46-year-old man, had a history of a stab wound of the tongue about 40 years ago. From several years after the injury, he had noticed an asymptomatic induration under the dorsal mucosa of the tongue. On examination the patient presented with a circumscribed round and cartilagelike hard mass of about 20mm in diameter was palpable under the dorsal mucosa of the tongue, and no signs of inflammation were observed. Enucleation of the mass was performed under general anesthesia. The surgically removed specimen was a cystic lesion containing a grayish brown mass in the cystic cavity. Histopathologically, the lesion was diagnosed to be an epidermoid cyst containing a wood chip in the cystic cavity. The case reported here strongly supports the hypothesis that epidermoid cysts may be caused by heteropic epithelial cells.