tailieunhanh - Chapter 054. Skin Manifestations of Internal Disease (Part 20)

Pink Lesions The cutaneous lesions associated with primary systemic amyloidosis are often pink in color and translucent. Common locations are the face, especially the periorbital and perioral regions, and flexural areas. On biopsy, homogeneous deposits of amyloid are seen in the dermis and in the walls of blood vessels; the latter lead to an increase in vessel wall fragility. As a result, petechiae and purpura develop in clinically normal skin as well as in lesional skin following minor trauma, hence the term pinch purpura. Amyloid deposits are also seen in the striated muscle of the tongue and result in. | Chapter 054. Skin Manifestations of Internal Disease Part 20 Pink Lesions The cutaneous lesions associated with primary systemic amyloidosis are often pink in color and translucent. Common locations are the face especially the periorbital and perioral regions and flexural areas. On biopsy homogeneous deposits of amyloid are seen in the dermis and in the walls of blood vessels the latter lead to an increase in vessel wall fragility. As a result petechiae and purpura develop in clinically normal skin as well as in lesional skin following minor trauma hence the term pinch purpura. Amyloid deposits are also seen in the striated muscle of the tongue and result in macroglossia. Even though specific mucocutaneous lesions are rarely seen in secondary amyloidosis and are present in only 30 of the patients with primary amyloidosis a rapid diagnosis of systemic amyloidosis can be made by an examination of abdominal subcutaneous fat. By special staining deposits are seen around blood vessels or individual fat cells in 40-50 of patients. There are also three forms of amyloidosis that are limited to the skin and that should not be construed as cutaneous lesions of systemic amyloidosis. They are macular amyloidosis upper back lichenoid amyloidosis usually lower extremities and nodular amyloidosis. In macular and lichenoid amyloidosis the deposits are composed of altered epidermal keratin. Recently macular and lichenoid amyloidosis have been associated with MEN syndrome type 2a. Patients with multicentric reticulohistiocytosis also have pink-colored papules and nodules on the face and mucous membranes as well as on the extensor surface of the hands and forearms. They have a polyarthritis that can mimic rheumatoid arthritis clinically. On histologic examination the papules have characteristic giant cells that are not seen in biopsies of rheumatoid nodules. Pink to skin-colored papules that are firm 2-5 mm in diameter and often in a linear arrangement are seen in patients with .