In their May 2007 JADA article, "Is Alveolar Ridge Keratosis a True Leukoplakia? A Clinico-Pathologic Comparison of 2,153 Lesions" (
JADA 2007;138[5]: 641–51[Abstract/Free Full Text]
), Dr. Angela Chi and colleagues have presented a large series of cases of alveolar ridge keratosis (ARK), finding that 97.9 percent of these cases are benign, with 10 cases being dysplastic. This is an important study that helps tighten the criteria for leukoplakia. We are reporting a similar series of cases from our pathology service1 that is an extension of our original research.2
We now refer to these cases as benign alveolar ridge keratosis (BARK, not just ARK) and believe that, unlike ARK, BARK is a single specific clinicopathologic entity that is completely benign. It is the oral equivalent of a common skin condition called lichen simplex chronicus (LSC), which is caused by chronic frictional (usually factitial from scratching) trauma.3 These two lesions, BARK and LSC, are identical histologically and are not mere hyperkeratosis, as is described for ARK.
The histologic features of BARK and LSC are specific and always reproducible: 1) hyperorthokeratosis (not hyperparakeratosis); 2) wedge-shaped hypergranulosis, papillary acanthosis forming long, tapered rete ridges, often confluent at the base; and 3) lack of significant inflammation unless ulceration is present.1 There is never atrophy and no dysplasia.
Even in the absence of clinical data, these findings are so characteristic that seeing the histopathology allows the pathologist to predict the clinical appearance—namely, a small white plaque on the retromolar pad or edentulous alveolar ridge mucosa. Unlike what has been reported by Dr. Chi and colleages, our criteria for BARK would not be merely hyperkeratosis with or without dysplasia.
More specific information regarding the 10 cases with dysplasia would have helped further define these cases, since information on pathology requisition forms vary considerably with regard to accuracy and detail. As pointed out by the authors, true leukoplakia of the gingiva/alveolar ridge certainly exists, and proliferative (verrucous) leukoplakia, a particularly ominous form of leukoplakia, frequently tends to involve the gingiva.4
Therefore, while BARK is a single entity (apples), ARK appears to constitute both BARK and true leukoplakias (apples and oranges). ARK is a white, keratotic lesion on the gingiva that is usually benign, but not always. In contrast, BARK is a white keratotic lesion on the gingiva, with a characteristic histology that is always benign and requires no follow-up or additional biopsy.
Nevertheless, the conclusions of the authors are important. As clinicians, we have seen these white papules and plaques on the retromolar pad that are often bilateral, and on the edentulous alveolar ridge. Removing them from the category of true leukoplakias increases the percentage of true leukoplakias that are dysplastic or malignant by, in this study, 23 percent and, in our study, 39 percent.1 It is such careful correlation of histopathology with clinical findings that will help us truly define leukoplakia with more stringent criteria.
TOP
REFERENCES
