F2Ch41b: Near the surface two whorls have evolved into keratin-filled lumens. The epithelium of the whorl blends with the superficial unit of the epidermis. In the lumen on the right, the keratinized lamellae are sharply defined and loosely aggregated. A granular layer is prominent and is confined to the domain of the whorl of cells. In the lumen on the left, cells, that retain the outline of their viable neighbors, have been sloughed; several of these cells show lavender cytoplasm with a loss of defined keratohyaline granules. Many of the sloughed, dead cells, away from the immediate area of the granular cells, retain their polygonal outlines, but show a loss of the lavender cytoplasmic staining. The keratinized debris is brightly acidophilic and compact. The pattern on the right is of a type that commonly is accepted as evidence of infundibular differentiation. Although the granular layer is prominent outlining the lumen on the left, the keratinized product more closely resembles that seen about the extremity of a clubbed hair shaft, as seen in catagen phenomena. At the bottom of the field , just to the right of a central vertical plane, a portion of a whorl is represented. About this whorl, there is a thin zone of mild cytolysis and dyskeratosis.
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