Malignant Potential of the Odontogenic Keratocyst

Abstract

odontogenic keratocyst (OKC) is considered a benign cyst that can assume a locally aggressive and destructive behavior. Atypia of its lining is uncommon, and frank malignant degeneration is rare. Presence of these changes may remain clinically undetected and carry a significant influence on treatment and outcome. A patient with OKC of the maxilla containing both verrucous carcinoma and squamous cell carcinoma (SCC) is presented. Literature is reviewed pertaining to the malignant potential of an OKC. CASE REPORTA 46-year-old man was initially seen with fullness and discomfort in his right anterior maxilla in August 1991. He had been unable to wear his maxillary partial denture for the preceding 6 months. Examination disclosed the presence of a 2-by 2-cm mass in the right anterior maxilla, with no changes in the overlying mucosa. Dental radiographs demonstrated a well-circumscribed radiolucency surrounding the apexes of the maxillary central incisors (Fig. 1). Curettage of the lesion was performed by an oral surgeon. Histopathology of the curetted material was confirmed to contain verrucous carcinoma with coexistent synchronous SCC.At the time of referral to us (September 1991), the patient's physical examination revealed a well-healed mucosal scar without detectable residual mass. Computed tomographic scans showed a smooth cystic bony defect with a small amount of fluid within the maxillary sinus. A partial maxillectomy and a nasal septectomy were subsequently performed. Resected margins were considered free of tumor. Histologic examination of the material was reviewed by Dr. John Batsakis of M. D.

KAI-1 and p53 expression in odontogenic cysts: An immunohistochemical (IHC) marker study

“…The epithelium of OKCs is believed to have an intrinsic growth potential and shows strong evidence of being neoplastic rather than developmental origin. [5,[21][22][23] OKCs also share the allelic loss of the same loci that have been implicated in the development of OSCCs, providing further proof for its being neoplastic in nature. [22,23] Thus, the results of our study show that although in radicular [ Figure 1] and dentigerous cysts [ Figure 2], there was positivity to KAI-1, in OKCs [ Figure 3], there was a significantly less expression.…”

“…[5,[21][22][23] OKCs also share the allelic loss of the same loci that have been implicated in the development of OSCCs, providing further proof for its being neoplastic in nature. [22,23] Thus, the results of our study show that although in radicular [ Figure 1] and dentigerous cysts [ Figure 2], there was positivity to KAI-1, in OKCs [ Figure 3], there was a significantly less expression. This lack of KAI-1 expression in OKCs could help to explain the differences in the clinical and pathological behaviour of OKCs and, according to what seems to be the pattern in several types of epithelial tumours, could be related to the increased aggressive behaviour, senescence.…”

“…This lack of KAI-1 expression in OKCs could help to explain the differences in the clinical and pathological behaviour of OKCs and, according to what seems to be the pattern in several types of epithelial tumours, could be related to the increased aggressive behaviour, senescence. [22,23] The tumour metastasis is suppressed mainly by an inhibition of cancer cell motility and invasiveness. [11,[24][25][26] As OKCs have recently been categorized as benign neoplasms with high recurrence rates as high as 60%, [5,[21][22][23] an attempt was made to use immunohistochemistry for KAI-1 and p53 in the aforementioned cysts to evaluate cell proliferation and the aggressive behaviour shown by them in the present study.…”

“…[19,20] The aforementioned features in these cysts have also caused several authors to consider them as benign neoplasms rather than cysts. [5,[21][22][23] In the recent WHO classification (2005) of odontogenic cysts and tumours, OKCs have been classified under benign tumours arising from the epithelium, and they have been renamed as keratinizing cystic odontogenic tumours. [21] The expression of KAI-1 is supposed to decrease in cancer cell lines, also OSCC.…”

Extensive odontogenic keratocysts of the maxilla: Review of the literature and report of six cases

“…Although atypia of the cyst lining is uncommon and frank malignant degeneration is rare, squamous cell carcinoma arising from an OKC has been reported (5,30,31). The summarized findings in reported cases of carcinomas arising within an OKC typically demonstrated a radiolucent lesion with occasional 'sunburst' appearance.…”