Distinguishing pseudoepitheliomatous hyperplasia from squamous cell carcinoma in mucosal biopsy specimens from the head and neck.

Abstract Context.—The differentiation of pseudoepitheliomatous hyperplasia from invasive squamous cell carcinoma is a difficult and frequently encountered distinction, especially in biopsy specimens from head and neck mucosa. The problem is compounded by inflamed and often poorly oriented tissue sections. Objective.—To distinguish pseudoepitheliomatous hyperplasia from invasive squamous cell carcinoma, utilizing a panel of antibodies to various epithelial and stromal elements (p53, matrix metalloproteinase 1, E-cadherin, and collagen IV) that has been shown to be useful in differentiating intestinal adenomas with invasive adenocarcinoma from displaced adenomatous epithelium. Design.—Thirty-three archival specimens (16 squamous cell carcinoma [12 with invasion and 4 with microinvasion] and 17 pseudoepitheliomatous hyperplasia) from head and neck mucosal locations were immunostained and examined by the authors. Results.—We found increased nuclear staining of the invasive tumor cells with p53. There was decr...