Squamous cell carcinoma arising within a maxillary odontogenic keratocyst: A rare occurrence

Abstract

Squamous cell carcinoma (SCC) arising within the lining of an odontogenic keratocyst (OKC) is a rare occurrence. Although potentially locally destructive, OKC is a benign odontogenic process that typically presents with clinical and radiographic features characteristic of a benign intraosseous neoplasm. We present the clinical and radiographic features of a maxillary mass that demonstrated SCC arising from the lining of an OKC. Although the initial clinical and radiographic presentation suggested an infection or malignant neoplasm, biopsies revealed an infiltrative well-differentiated SCC contiguous with and arising from the focus of a pre-existing OKC. The patient subsequently underwent a type II hemi-maxillectomy with neoadjuvant chemoradiation. This report discusses the clinical and radiographic features associated with intraosseous malignancies, especially those arising from an otherwise benign odontogenic lesion. While the majority of OKCs are benign, the current report illustrates the potential for carcinomatous transformation within the lining of an OKC.

Keywords: Carcinoma, Squamous Cell; Cell Transformation, Neoplastic; Maxilla; Odontogenic Cysts.

Fig. 1. Preoperative panoramic radiograph demonstrates extensive bone destruction in the right maxilla. The lesion is ill-defined, with ‘blow-out’ of much of the right antrum, also involving the right orbital floor. The maxillary canine is impacted by a pericoronal radiolucency that appears well defined.

Fig. 2. A and B. Axial bone window and coronal soft tissue algorithms of CT show the impacted right maxillary canine surrounded by a large, well defined, low intensity lesion growing more along the bone than buccal palatal expansion, extending through the palate and expanding and thinning the buccal cortical border adjacent to the right canine. C and D. Axial bone window and coronal soft tissue algorithm of CT show erosion of much of the floor, anterior and lateral walls of the right maxillary sinus, obliteration of the entire right antral cavity and invasion of the surrounding soft tissue by the lesion. The right lateral nasal wall adjacent to inferior concha and ipsilateral orbital floor are also eroded and edema of the superficial soft tissue on the right side is evident.

Fig. 3. Squamous cell carcinoma arising in an odontogenic keratocyst. A. Low-power magnification demonstrates the cyst lining and a satellite cyst within the wall. B. A satellite cyst demonstrates classic odontogenic keratocyst lining epithelium. Note the regimented basal cells and the uniform thickness of the epithelium. C. Odontogenic keratocyst lining demonstrates dysplastic changes. Note the nests of SCC arising from and contiguous with the cyst lining. D. A high-power view shows the infiltrative squamous cell carcinoma.

Fig. 4. A postoperative axial computed tomography scan reveals total right maxillectomy with right orbital exoneration and free flap reconstruction. No residual tumor or fluid was detected.