Carcinoma arising in an odontogenic keratocyst with orbital invasion.

A 54-year-old black female presented with proptosis and reduced visual acuity of the left eye. Computerized tomography (CT) revealed tumor involvement of the left cavernous sinus and posterior orbit. The patient had a nineteen year history of a left-sided jaw tumor which recurred despite surgical and radiation therapy. Biopsy demonstrated a parakeratinized odontogenic keratocyst with areas of transformation into an invasive squamous cell carcinoma. Although a parakeratinized odontogenic keratocyst may be locally invasive, to our knowledge, no case of a parakeratinized odontogenic keratocyst involving the orbit or cavernous sinus previously has been reported.