Pretibial myxedema, first described by Watson-Williams, in 1895, has been almost invariably associated with exophthalmos, and as a result, the same etiology has been proposed. Over 100 cases 1 have been reported. The disorder probably occurs more frequently than this number would indicate, because of the failure to make a specific search of the pretibial region on the routine physical examination.
Grossly, pretibial myxedema characteristically appears as firm brown or orange-colored plaques bilaterally but not always symmetrically, on the lower anterior portion of the legs or dorsum of the feet. Initially only the skin over these areas is thickened, but later varying-sized plaques appear and develop a pigskin or orange-peel appearance. The advanced lesion may resemble brawny lymphedema. Microscopically these lesions have the appearance of classical myxedema. In the cutis one finds edema along with fraying and homogenization of the connective tissue. Large amounts of mucinousstaining material are deposited between
WARTHIN TA, BOSHELL BR. Pretibial MyxedemaTreated with Local Injection of Triiodothyronine. AMA Arch Intern Med. 1957;100(2):319–321. doi:10.1001/archinte.1957.00260080145029