F4Ch40d: Components, each consisting of distinctive cells (one component having qualities of the basal unit and the other having qualities of the superficial unit of the epidermis), outline a fibrous stroma. In this field, the cells of the basal unit-like population are basaloid but do not have the fully developed qualities of clear cells. On the other hand, to the left, some of the cells with superficial unit-like qualities have vacuolated cytoplasm. As discussed for other examples, this alteration is common; it seems to anticipate catagen-like phenomena with cytolysis and dyskeratosis. In the process, lytic defects will develop. If, in the process of cytolysis, the basal unit-like component is involved, interruptions in the basal layer may be produced. In this event, the cleft come to abut upon mesenchyme. The response is an ingrowth of connective tissue as an inlay for the empty defect. The nipple-like protrusion, from the population of cells on the left, seems to be an extension from a basal unit-like component but the cells show dyskeratosis and loss of polarity; there is no basal layer. We should accept the islands and cords of acidophilic cells in the fibrotic stroma as marker for an epithelial domain, that, in the process of cytolysis, has lost part of its domain to stroma. The surviving cells are also degenerating, hence the intense cytoplasmic acidophilia. The lesion could be characterize as being, in part, in the grip of catagen phenomena - some of these follicular hamartomas of the butterfly area of the face may in foci, and in distorted patterns, recapitulate the phenomena of a catagen phase.
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