Ultrastructural findings supporting the angioblastic nature of the so‐called adamantinoma of the tibia

Abstract

EM of a case of adamantinoma of the tibia showed features which support a mesenchymal angioblastic origin rather than epithelial. Comparison was made between tissue from this tumor and a squamous cell carcinoma of the femur arising in chronic osteomyelitis. In adamantinoma no desmosomes were found between tumor cells and their cytoplasmic ultrastructure showed features of mesenchymal cell type including evidence of pinocytic activity and bundles of filaments resembling hyperplastic endothelial cells. The stroma showed features similar to fibrous dysplasia of bone with fibroblasts, histiocytes and fibrolipoblastic lipid-laden mesenchymal cells. Adamantinoma of the tibia should be considered an angioblastic bone tumor.