F1Ch41a (R695): This is a portion of a larger lesion. In this area, follicle-like patterns are well developed. Columns of squamous cells are vertically oriented. At the periphery, some of the columns fold inward; they are confluent with neighbors. Whorls of cells, some containing prominent keratohyaline granules, mark patterns that anticipate the formation of a lumen. Near the deep extremities of the columns, whorls are numerous. Bordering the whorls, some of the keratinocytes have perinuclear vacuoles. Centrally, the widest column, at its extremity, shows small zones of cytolysis. The last column to the right shows an empty, rounded defect. In the same area, at the extremity of the area of confluence, stroma distorts the contour of the epithelial component; a basal layer cannot be identified in this area. The papillary dermis is widened, and contains a mild infiltrate of inflammatory cells.
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