Linear hyperpigmentation with extensive epidermal apoptosis: a variant of linear lichen planus pigmentosus?

We report 3 female patients who rapidly developed pigmented patches in a linear arrangement. Histologically there was minimum epidermal basal cell damage and bandlike lymphocyte infiltration in the dermis, but focal massive apoptotic materials positively stained with antikeratin antibody were prominently seen in the papillary and subpapillary dermis. We considered these cases as a variant of linear lichen planus pigmentosus with unique histologic change of severe epidermal apoptosis.

Expression of 67-kDa elastin receptor in annular elastolytic giant cell granuloma: elastin peptides induce monocyte-derived dendritic cells or macrophages to form granuloma in vitro.

Annular elastolytic giant cell granuloma (AEGCG) is characterized by non-palisading granuloma and elastophagocytic giant cells. Granulomas consist of structured masses of macrophages, dendritic cells, and T lymphocytes which play an essential role in granuloma formation. Two lineage systems of dendritic cells and macrophages originated from peripheral blood monocytes have been established in vitro.

Coexistence of pseudoxanthoma elasticum-like papillary dermal elastolysis and linear focal dermal elastosis.

An 89-year-old Japanese woman had pseudoxanthoma elasticum-like papillary dermal elastolysis on the neck and linear focal elastosis on the flexor aspects of the legs and thighs. The lesions of both diseases had similar histologic patterns-loss of elastic fibers in the papillary dermis and accumulation of normal-appearing elastic fibers in the subpapillary or mid dermis. Immunohistochemical analysis showed elastin, and microfibril-associated proteins (fibrillin 1 and 2 and microfibril associated glycoprotein 1 and 4) were absent or decreased in the papillary dermis and present in the accumulated elastic fibers in both lesions.

Type XVI collagen is expressed in factor XIIIa+ monocyte-derived dermal dendrocytes and constitutes a potential substrate for factor XIIIa.

We have previously reported that connective tissue cells in the superficial dermis preferentially express alpha1(XVI) collagen rather than those in the lower dermis. Double immunofluorescence labeling using the antibodies for alpha1(XVI) collagen and factor XIIIa (plasma transglutaminase), which is a marker of dermal dendrocytes, demonstrated that both antibodies reacted with the same cells in the superficial dermis of normal skin as well as the lesional skins of dermal dendrocyte-related disorders, dermatofibroma, and psoriasis. Dermal dendrocytes are considered to be established by a culture of peripheral blood monocytes in the presence of granulocyte macrophage-colony stimulating factor and interleukin-4.