The stroma is the supporting tissue of the bone marrow. The following cells are part of the stroma: fibroblasts, endothelial cells, fat cells, osteoblasts, osteoclasts, smooth muscle cells, macrophages and mast cells.
Macrophages and mast cells can be increased in different states of the bone marrow. Therefore, they must be interpreted in the bone marrow examination. in the bone marrow film, fat cells are visible as fat vacuoles. The other cells of the stroma are rarely seen in the bone marrow, since they are not aspired in bone marrow puncture or are mainly located in the dense bone marrow spicules. They have no role in hematological diseases.