Morphological Diversity of Pretibial Myxedema and Its Mechanism of Evolving Process and Outcome: A Retrospective Study of 216 Cases

Figure 11

Large amounts of mucopolysaccharide deposits, numbers of newly formed capillaries, and a perivascular lymphocyte infiltrate at active stage of PTM. (a) H&E ×4. The epidermis was essentially normal. Just below the epidermis is a relatively unaltered strip of papillary dermis. The upper layer of reticulate dermis was obvious mucin degeneration with widely separated, frayed, and fragmented collagen bundles. In the lower layer of reticulate dermis were seen numbers of newly formed capillaries, a perivascular inflammatory cell infiltrate, and proliferation of fibroblasts. (b) H&E ×20 and (c) H&E ×40. Perivascular and dermal lymphocyte infiltrates were seen. (d) H&E ×4. Alcian blue staining showed large amounts of mucopolysaccharide deposits in the lower layer of papillary dermis and reticulate dermis. (e) ×40. Immunohistochemical staining by anti-CD8 monoclonal antibody showed a large proportion of infiltrates were CD8+ T lymphocytes (arrows) in the dermis and perivascular regions. (f) ×40. Immunohistochemical staining by anti-CD4 monoclonal antibody showed a CD4+ T-cell infiltrate in the dermis and perivascular regions.

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