Ch21 Vascular Changes
Polypoid FP

Buster (the plight of feral cats)

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Fig. 1 Ch21 (R4919): Fibrosis is prominent near the dermal-epidermal interface, about the follicle, and in peri-vascular areas. These are all components of the “adventitial dermis.” The peri-follicular component is concentric laminated; the component in apposition to the epithelial component is brightly acidophilic. Vessels are increased in number and are ectatic.The reticular dermis, that component beyond the adventitial dermis shows rather prominent collagenolysis. There are mild peri-follicular infiltrates of lymphoid cells. Some of the peri-vascular fibrous tissue is hyalinized. At its extremity, the follicular bulb is misdirected. The follicle shows a trichogenic component; it is miniaturized.

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Fig. 2 Ch21 (R4919): In cross-section, the follicular lumen contains a vellus hair. The perifollicular component is laminated; the lamellae nearest the epithelium are compacted and the fibrous tissue is brightly acidophilic. Vessels are ectatic and the are areas of perivascular hyalinization.

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Fig. 3 Ch21 (R4919): Vessels are ectatic; the extent of perivascular fibrosis is variable. A vessel near the top of the field shows a vascularized papilla that has been cut in cross-section; the pattern is interpreted as evidence of an organized thrombus. The neighboring reticular dermis shows a pattern of collagen-poor fibrous tissue. The widely spaced collagen bundles are thin. The scattered multi-nucleated giant cells may, in part, provide an explanation for the process of collagenolysis. In areas, a proteinaceous (mucinous?) material is evident among the altered collagen bundles.

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Fig.4 Ch21 (R4919): There is a mild hyperplasia of clear cells in the basal unit of the epidermis; some of the cells are melanocytes while others are of questionable  nature. Focally, a thin basement membrane is recognizable. The basal unit of the epidermis is poorly developed. There is liquefaction degeneration at the D-E interface.There is hyperkeratosis and hypergranulosis. An abnormal fibrous matrix has been substituted for a normal papillary dermis. The abnormal fibrous matrix extends into the upper portion of the reticular dermis. At the extremity of the fibrosing process, collagen bundles of the reticular dermis are thin, wavy, and loosely spaced in a clear matrix. Vessels are ectatic. To the right, a small rounded defect contains an acidophilic body in its lumen; this probably represents a platelet thrombus.

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Fig. 5 Ch21 (4919): Vacuolar changes are prominent at the D-E interface. There is mild melanocytic hyperplasia at the D-E junction. This field represents the same general area as Fig. 4. The rounded, “platelet thrombus” marks the extremity of an anatomically defined area that extends from the dermal-epidermal interface; in this area, collagen bundles are brightly acidophilic. This zone, which is based upon the  D-E interface, by its configuration, could be interpreted as an area in which a rete ridge has undergone lysis resulting in a defect that has been inlaid with the altered fibrous tissue; perhaps, basement membrane material has been incorporated in the acidophilic collagen bundles.

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Fig. 6 Ch21 (4919): The epidermis shows hyperkeratosis, a prominent granular layer, and a accentuation of the patterns of a hyperplastic superficial unit; a basal unit is not well defined. There is liquefaction degeneration at the dermal-epidermal interface. Some of the basal cells show acidophilic cytoplasm and karyolysis. To the left of the center of the field, near the D-E interface, there is a small cluster of colloid bodies. A band of fibrous tissue separates the epidermis from the reticular dermis; Fibrous lamellae that are parallel to the epidermis mark the lower margin of this band of fibrous tissue. Within the band collagen bundles are closely aggregated in abnormal patterns. There are scattered melanin deposits and melanophages in the band of fibrous tissue. Only at the far right can a thin basement membrane be defined at the D-E junction. Over the band of altered fibrous tissue, it is difficult to define a basement membrane (although, the bundles of fibrous tissue may represent in part basement membrane material). The reticular dermis shows some lysis of collagen bundles; collagen bundles are widely spaced in a clear matrix. Vessels are ectatic.

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Fig. 7 Ch 21 (4919): The epidermal changes qualify as those of a cell-poor variant; liguefaction degeneration is a prominent feature. Coarse (coarser than those of a normal papillary dermis) collagen bundles extend to the D-E interface. A zone of abnormal fibrous tissue extends from the D-E interface into the dermis. An interface with the reticular dermis is ill-defined but, in the reticular dermis, collagen bundles are widely spaced; the intercellular matrix is clear or faintly mucinous. Vessels are ectatic. Some of the small vessels form angiomatoid pattrns. Some of the vessels have thickened, hyalinized walls. There are scattered giant cells.

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Fig. 8 Ch21 (4919): In this field, vascular changes in an altered reticular dermis are emphasized. Focally, the matrix is faintly myxoid.

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