Is alveolar ridge keratosis a true leukoplakia?: A clinicopathologic comparison of 2,153 lesions

Alveolar ridge keratosis (ARK) is not widely recognized as a distinct clinicopathologic entity, and it often is included in studies of oral leukoplakia (OL), thereby implying premalignant potential. The authors' objectives were to characterize the clinicopathologic features of ARK and determine whether removing ARK from the OL category would significantly affect the prevalence of dysplasia or carcinoma in OL.

The authors conducted a retrospective consecutive case review of 477 ARK cases and 1,676 OL cases submitted to their biopsy service from 1995 through 2004. The authors defined ARK as a white plaque without erythema or ulceration and limited to the retromolar pad or edentulous ridge.

Microscopically, most ARK cases (97.9 percent) exhibited hyperkeratosis without dysplasia. The few dysplastic cases (2.1 percent) were associated with one or more of the following: verrucous appearance, tobacco or alcohol use, multiple OL lesions and previous oral squamous cell carcinoma. Excluding ARK from OL increased the percentage of OL cases exhibiting dysplasia or carcinoma from 20.2 percent to 24.8 percent. Including versus excluding ARK resulted in good but less than excellent agreement in the OL case definition (kappa = 0.6128).

ARK in patients without high-risk habits or other clinical warning signs appears to be a distinctly different lesion from OL, with a much smaller proportion of dysplasia or carcinoma evident among ARK versus OL cases. However, prospective studies are needed to confirm this hypothesis.

Although most cases clinically consistent with ARK are benign hyperkeratoses, dysplasia or carcinoma can be excluded only by means of biopsy and histopathologic examination.