S3C21P9LPMisc


S3C21P9-1: A cell-poor, subepidermal bulla is represented. There are prominent clusters of melanophages in the papillary dermis. The epidermis forming the roof of the bulla shows compact hyperkeratosis ( bullous lichen planus).

S3C21P9-2: Colloid bodies are clustered along the floor of the vesicle. Melanophages are prominent in the papillary dermis.


S3C21P9-3: The roof of the defect in this example of bullous lichen planus shows characteristic features; there is compact hyperkeratosis, a prominent granular layer, and a preponderance of keratinocytes showing the features of a hyperplastic superficial unit (i.e., surviving cells show features of terminal differentiation). The degenerating keratinocytes, along the deep surface of the roof of the vesicle, are oriented parallel to the surface. Histiocytes are interspersed among the keratinocytes in this “basal” row of cells.

S3C21P9-4: In this lesion, the lichen planus-like features are somewhat altered. Ectatic follicular ostia are regularly spaced. The intervening epidermis is thin with irregular rete patterns. The superficial portion of the widened papillary dermis is edematous and cell-poor. The granular layer is uniformly prominent. At the deep extremities of the follicular ostia, columns of hypertrophied, pale keratinocytes extend close to the boundary between the widened papillary dermis and the reticular dermis. As is often the case, the columns appear to be altered follicles. Lymphoid infiltrates hug, and are most prominent at, the extremities of the columns. The patterns are those of a cytolytic, cell-mediated reaction (i.e., a lichenoid reaction). Blue arrows point to lytic defects. The patterns at the actual dermal-epidermal interface have qualities of a senescent lichenoid reaction. This is hypertrophic lichen planus. This type of lesion often is encountered on the lower extremity in association with some degree of angiodermatitis.

S3C21P9-5: At a higher magnification, the lytic cleft (blue arrows) interrupts the basal layer of the epithelial column; the process is erosive. The erosive nature of the cell-rich process is the basic injury in lichen planus-like reactions.

S3C21P9-6 (same lesion as P9-4&5): There is no basal unit as such. Cells of the superficial unit extend to the basement membrane zone, or to the cleft on the right at the level of this zone. A lytic defect on the right contains lymphocytes, histiocytes, and necrotic cells. Scattered “colloid” bodies are present in the dermis; their presence, at this level, might be taken as evidence that, at one time, they were viable cells in an epidermal domain. Their presence in the dermis at this level provides evidence that a defect in the epidermal domain has been inlaid with fibrous tissue and that necrotic cells were then entrapped in the newly formed tissue.

S3C21P9-7: Lichen plano-pilaris showing early senescence in both surface and follicular domains.

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