LICHEN MYXEDEMATOSUS (DIFFERENTIATION FROM CUTANEOUS MYXEDEMAS OR MUCOID STATES)

[摘要] A study was made of the histopathologic and clinical findings in 3 cases of Lichen myxedematosus at the Mayo Clinic. In addition, material in 8 other probable cases was furnished by several physicians. Lichen myxedematosus, also referred to formerly as generalized localized myxedema, occurs usually as a generalized lichenoid eruption, less frequently in a discrete papular form or as lichenoid plaques and rarely in the form of urticarial plaques. Lichen myxedematosus differs from other types of cutaneous myxedema (mucoid states) in that it is not associated with thyroid disease or apparently with any other endocrine disturbance. Lichen myxedematosus is characterized histologically by deposition of large amts. of mucin, usually in the form of discrete papules in the upper part of the cutis. It should be distinguished from localized solid edema or circumscribed or pretibial myxedema associated with exophthalmic goiter on the one hand and from the various cutaneous changes seen in association with true myxedema on the other. The condition has been confused in the past with papular forms of scleroderma and also with many dermatoses having a lichenoid eruption. A working classification is presented of the various forms of cutaneous myxedema and mucoid states. The pathogenesis of lichen myxedematosus is unknown, but a disturbance in the balance of hyaluronidase in the skin may be a factor. The condition has failed to respond to any form of treatment, including use of various endocrine preparations. Local injections of hyaluronidase, as advocated for localized solid edema or pretibial myxedema, have produced equivocal results. In the authors''opinion lichen myxedematosus, or whatever term is accepted, represents a distinct entity that previously has been confused with many other conditions.