IADR Abstract Archives
Determining the Malignant Nature of Dysplasia in Oral Lichenoid Lesions
Objectives: Two subtypes of lichenoid dysplasia (LD) have been proposed, with differing risks of malignant transformation. However, no research has been done to authenticate this hypothesis. The study objective was to determine whether there are two subcategories within LD, one with primary lichenoid and secondary dysplastic features (L1D2), and the other with primary dysplastic and secondary lichenoid features (D1L2), and to compare the proportion of malignant progression in these groups.
Methods: Patients with a diagnosis of low-grade LD, no history of head and neck cancer, and who had at least 5 years of follow-up were eligible to participate in this nested case-control study. A sample size of 11 cases and 33 controls is required to detect a significant difference with a significance level of 5% and 80% power on 2-tailed tests. Cases are defined as patients that progressed to severe dysplasia, carcinoma in situ, or squamous cell carcinoma; controls are defined as those that did not progress. Immunohistochemistry (IHC) was performed to assess for basal cell and/or basement membrane (BM) degeneration using collagen IV – an integral basement membrane protein. Inferential statistical analysis was performed using Chi-square test and logistic regression.
Results: 13 cases and 39 controls have been selected, and IHC staining and interpretation completed for 30 patients (4 progressors and 26 non-progressors). 15% of non-progressing cases and 50% of those that did progress exhibited an intact BM, however, these preliminary findings reveal no significant difference between groups (P=0.169). Rather, progression was significantly associated with a diagnosis of moderate dysplasia (P=0.020).
Conclusions: Preliminary findings do not support the existence of two LD subtypes: D1L2 – characterized by a lack of BM degeneration, and L1D2 – with BM degeneration. Progressing cases were more likely to be a higher grade of dysplasia, illustrating that dysplasia seen in lichenoid lesions do still have inherent malignant risk.
Methods: Patients with a diagnosis of low-grade LD, no history of head and neck cancer, and who had at least 5 years of follow-up were eligible to participate in this nested case-control study. A sample size of 11 cases and 33 controls is required to detect a significant difference with a significance level of 5% and 80% power on 2-tailed tests. Cases are defined as patients that progressed to severe dysplasia, carcinoma in situ, or squamous cell carcinoma; controls are defined as those that did not progress. Immunohistochemistry (IHC) was performed to assess for basal cell and/or basement membrane (BM) degeneration using collagen IV – an integral basement membrane protein. Inferential statistical analysis was performed using Chi-square test and logistic regression.
Results: 13 cases and 39 controls have been selected, and IHC staining and interpretation completed for 30 patients (4 progressors and 26 non-progressors). 15% of non-progressing cases and 50% of those that did progress exhibited an intact BM, however, these preliminary findings reveal no significant difference between groups (P=0.169). Rather, progression was significantly associated with a diagnosis of moderate dysplasia (P=0.020).
Conclusions: Preliminary findings do not support the existence of two LD subtypes: D1L2 – characterized by a lack of BM degeneration, and L1D2 – with BM degeneration. Progressing cases were more likely to be a higher grade of dysplasia, illustrating that dysplasia seen in lichenoid lesions do still have inherent malignant risk.