Histologic and Histomorphometric Comparative Study of Oral Lichen Planus Versus Oral Lichenoid Reaction

Aim

Oral lichen planus (OLP) is a T-cell-mediated chronic inflammatory disease classified as an oral potentially malignant disorder (OPMD) and increased transformation risk to oral cancer. Oral lichenoid reactions (OLRs) share the clinical manifestations of OLP. This study aimed to determine histomorphometric changes in OLPs and OLRs in comparison to the healthy control, which helps to plan for the establishment of diagnostic criteria.

Materials and Methods

This cross-sectional prospective study was conducted on a total of 75 tissue-embedded paraffin-block samples, including OLPs (n = 25), OLR cases (n = 25), and healthy control individuals (n = 25). The study groups were compared by chi-squared, Fisher's exact, and one-way ANOVA tests. A p-value less than 0.05 was considered statistically significant.

Results

Comparison of the nuclear area and cellular area showed a statistically significant difference between study groups in basal and parabasal layer (P < 0.05). Comparison of the nuclear-to-cytoplasm ratio showed a statistically significant difference between study groups in basal (P < 0.05) but not in the parabasal region (P = 0.681).

Conclusion

We showed a significant difference in the nuclear and cellular area, nuclear-to-cytoplasm ratio between OLPs and OLRs, and healthy controls, but there was no statistically significant difference between OLPs and OLRs. Thus, these parameters cannot be applied to differentiate diagnoses between OLPs and OLRs.

Drug-induced oral lichenoid reactions: a real clinical entity? A systematic review

PURPOSE

Drug-induced oral lichenoid reactions (DIOLRs) have been extensively reported in the literature, but the validity of the causality relationship between any drug and the oral lichenoid lesions (OLLs) still remains questionable. We sought to determine whether this causality relationship really exists, whether a resolution of the oral lesions upon withdrawal occurs, and what the most common alleged offending medications are.

METHODS

Nine electronic databases from January 1966 to December 2016 were systematically searched to identify all relevant studies selected with specific inclusion criteria (a clinical and histopathological diagnosis of DIOLRs, and clearly statement on the systemic offending medication). Searched terms included but not limited to oral lichen planus/oral lichenoid lesions/oral lichenoid reactions, the adverse effects of medication, and drug-induced. Statistical analyses conducted.

RESULTS

The search retrieved a total of 817 articles, of which only 46 were included into a qualitative synthesis: 40 case reports/series and 6 studies. The causality assessment was done only in 14.8% of cases with the C-D-R protocol. The Naranjo algorithm was not reported in the majority of cases (98.2%). Culprit medication was withdrawn in 68.5% of the cases, obtaining a partial or complete resolution without treatment in 16.7% of cases and with treatment in 27.7% of cases. The median number of culprit medication(s) described was 1 with the most frequent ones being Methyldopa (20.37%), Interferon (IFN)-alpha (11.11%), and Imatinib and Infliximab (9.26%).

CONCLUSION

This systematic review demonstrated that there is no strong scientific evidence to support the causal relationship between any drug and oral lichenoid lesions; therefore, in all reviewed cases, we must question whether the DIOLRs represent a real and separate clinical entity. Further and more thorough investigations using one of the available algorithms for adverse drug reaction are warranted.