Multiple cutaneous fibromyxomas: a light and electron microscopic study

A 27-year-old woman developed many nodular lesions, ranging in diameter from 3 mm to 15 mm and clinically indistinguishable from dermatofibromas. Light microscopic examination showed large amounts of mucin, fibroblasts and histiocytes throughout the dermis. Electron microscopic study revealed wide electron lucent areas and long branching winding electron dense threads occupying the ground substance. While dilated cisternae of endoplasmic reticulum containing a finely granular material characterized the fibroblasts, banded structures, intracellular collagen and myelinoid figures were prominent in the histiocytes. The term fibromyxoma is introduced to designate this tumor.