Myogenic cells in Kaposi's sarcoma: an ultrastructural study.

An ultrastructural study of a metastatic Kaposi's sarcoma in a cervical lymph node demonstrated the presence of endothelial cells, smooth muscle cells, fibroblasts and myofibroblasts. Some of these cells exhibited phagocytic activity in relation to extravasated red blood cells. The ultrastructural features favour the suggestion of an origin of Kaposi's sarcoma from pluripotential mesenchymal cells which may differentiate into more specialised cell types including endothelial, smooth muscle, fibroblastic and myofibroblastic cells.