| Stratified squamous epithelium covering the tissue is ulcerated. The epithelial tissue is proliferative and contiguous in places with a mass present below. The underlying collagen is infiltrated by a solid mass of proliferating squamous epithelial tissue. The epithelial tissue occurs as masses, trabeculae or nests with minimal stromal tissue. The epithelial cells are variable in size; they have large nuclei with prominent nucleoli; mitotic figures are frequent. | | Stratified squamous epithelium covering the tissue is ulcerated. The epithelial tissue is proliferative and contiguous in places with a mass present below. The underlying collagen is infiltrated by a solid mass of proliferating squamous epithelial tissue. The epithelial tissue occurs as masses, trabeculae or nests with minimal stromal tissue. The epithelial cells are variable in size; they have large nuclei with prominent nucleoli; mitotic figures are frequent. |