- Lichen planus is very common mucocutaneous disease affecting areas in oral cavity and skin as well. In 1869 , it was first described by Wilson. He found similarity between the lichens growing on flat rocks to skin lesions of lichen planus.The term "lichen planus" is due its characteristic appearance .
In a research conducted by Dr Shetty it was found that there were significant differences between the two when they were ultrastructurally compared. Cytoplasmic processes,intercellular spaces ,and sign of degeneration were shown by the basal layer.Erosive form showed elongated,narrow or irregular cytoplasmic projection on the other hand short and broad based projection were shown by non erosive form .
Dr Devicharan Shetty took a total of 20 cases of oral lichen planus and divided into nonerosive and erosive forms which laid its basis on clinical pattern and by histopathological analysis were confirmed as lichen planus.At the time of extraction of third molar as control, one case of normal gingival tissue was observed. Specimens of tissue obtained were cut into two halves and in appropriate fixatives were fixed. For formalin-fixed paraffin-embedded tissue section, 4 micrometer were stained with eosin and hematoxylin for confirmatory diagnosis of lesional .
This was a observed by Dr DC Shetty and he concluded it in his research that regular stratification in normal epithelium was showed by Basal cells . A significant amount of difference was found between the two forms when ultrastructurally compared. In many cases the intercellular spaces of the basal layer were penetrated by lymphocytes. In erosive form the desmosomes number was decreased also Apoptotic change were more marked in it . Similar changes in the spinous layer were observed but to a smaller extent .
Basal lamina showed two different kinds of alterations : Duplication and breaks or both. In erosive form breaks and discontinuities was encountered more frequently whereas in both forms of OLP the duplication was encountered.The boundary of connective tissue - non connective tissue is delimited by basal lamina . It also attaches epithelial cells with the connective tissue. The orderly organization of these tissues is disturbed by injuries and defects in basal lamina .Changes in basal epithelial cells results in changes in basal lamina since basal lamina is an epithelial cell product.
Elongated, irregular cytoplasmic or narrow projections were observed in erosive form on the other hand broad based projections in non erosive form were evident. Features as cytoplasmic blebs. Vacuolization, tonofilament bundles ,presence of apoptotic bodies and disruption of cell organelles were observed during Dr Devicharan Shetty’s research.
Between basal cells and high up in spinous layer few lymphocytes were also observed entrapped. Numerous medium and small sized lymphocytes were found showing signs of activation
juxta epithelially .
Tydesley and Appleton found that stratum basale cells formed an irregular layer where at times large or rather wide intercellular spaces were present. Vacuolization of cytoplasm was shown by some cells . The aggregates of ribosomes , tonofibrils, and mitochondria were contained when cytoplasm was condensed .