Abstract
Background : Orthokeratotic dysplasia (OKD), a variant of epithelial dysplasia, is a precancerous condition of the oral mucosa. OKD is defined histopathologically as an oral mucosal condition that shows hyperorthokeratosis, hypergranulosis, and a cytokeratin (CK) 10 positive immunoprofile. We report herein on two cases of OKD diagnosed by oral scraping cytology.
Case : Case 1 : A 52-year-old man presented with leukoplakia of the palate. The cytological findings showed keratinized anucleated squamous cells comprised a large proportion of the collected cells. Immunocytochemically, these cells were positive for CK10, and negative for CK13. Histological specimens showed hyperorthokeratosis and hypergranulosis of oral mucosa. On immunohistochemical examination, the lesion was CK10 (+)/CK13 (−)/CK17 (−). These findings supported the diagnosis of OKD.
Case 2 : A 65-year-old man presented with two torose leukoplakia lesions on the left upper gum. On cytology, keratinized anucleated squamous cells accounted for 80 percent of collected cells, and CK10 (+)/CK13 (−) immunocytochemically. Histopathologically, both lesions were diagnosed as OKD.
Conclusion : OKD is a new entity of the oral mucosa related to squamous cell carcinoma. However, very few cytologists are currently familiar with OKD. It is important to keep OKD in mind as one of the differential diagnoses and use immunocytochemical staining for CK10 or CK13, when we encounter many keratinized anucleated squamous cells in the scraping cytology of oral leukoplakia.
