Histopathologic examination showed hyperkeratosis of epidermis, increased thickness of the granular layer and dilation of subpapillary vessels filled with red blood cells.
Such involvement of dermal lymphatics gives the grossly thickened, erythematous, and rough skin surface with the appearance of an orange peel ("peau dorange" for you francophiles).
The change of the control group's histomorphology was clear: the incrassation of synovial lining cells, the infiltration of Inflammatory cells and the erosion of nephelium of blood vessels on hones.