Oral discoid lupus erythematosus. III. A histopathologic study of sixty-six patients.

A detailed histopathologic study was conducted blindly on biopsy specimens from 66 patients with oral discoid lesions (oral DLE) mixed in random order with biopsy specimens from control groups of 25 cases of oral lichen planus (LP), 25 cases of oral leukoplakia, 13 cases with an uncertain diagnosis termed DLE? LP? and 7 cases of galvanic lesions related to amalgam fillings. Fifty-two histopathologic variables were examined, and a ranking was calculated for the variables that provided the best discrimination between the subgroups of clinically typical oral DLE and LP and between typical DLE and leukoplakia, respectively. Histopathologic variables not previously described in oral DLE but characteristic of this disease were identified: multinucleated epithelial cells containing three or more nuclei and the presence of epithelial islands in the connective tissue. Patients with systemic lupus erythematosus (SLE) in addition to oral DLE showed generally the same histopathologic features as those without SLE. The inflammatory infiltrates were slighter and more diffuse among the SLE patients as compared to the non-SLE patients. The simplest possible combination of histopathologic variables diagnostic for oral DLE consisted of the following five: (1) hyperkeratosis with keratotic plugs, (2) atrophy of the rete processes, (3) deep inflammatory infiltrate, (4) edema in the lamina propria, and (5) thick patchy or continuous PAS-positive juxtaepithelial deposits. This combination is suggested as new histopathologic criteria for oral DLE. These criteria were tested among clinically atypical cases of DLE and the other groups of mucosal lesions, with a sensitivity of 92% and a specificity of 96% against both LP and leukoplakia for the presence of two or more of the five criteria.