👉 A syncytioma, also known as a syncytial tumor or syncytiocytic tumor, is a type of cancer that occurs in the cells of the blood and bone marrow. It's caused by abnormal growth of cells from two different parts of the body - the bones (osteoblasts) and the blood (erythrocytes). These cells are not normally found together but can form a tumor when they grow together, creating a cluster of cells in the bone or blood