AMYXOMA consists of stellate or spindle-shaped cells in a loose matrix which contains mucoid material (most likely hyaluronic acid), reticulum, and collagen fibers. Thus, histologically, myxoma resembles primitive mesenchymal tissue and umbilical cord matrix.
Myxomatous tissue may occur in the skin in several benign conditions. Ganglion is a term describing a cystic tumor-like lesion microscopically similar to myxoma, found near joints and tendons in the subcutaneous tissues. Papular and localized plaque-like accumulations of myxomatous nature are found in the skin in hypothyroid and hyperthyroid states and also where no thyroid pathology is demonstrable, as in lichen myxedematosus (papular mucinosis).1 In addition, various neoplasms of the skin (sarcoma, fibroma, lipoma, etc.) may show appreciable amounts of myxomatous tissue.
Malignant myxoma, or myxosarcoma, is similar microscopically to the benign types described above, but the stellate cells show variations in shape, in size, and in staining of