This is a photo micrograph of red blood cells arrayed around a white blood cell (A)(neutrophil). The red blood cells are the oxygen carrying cells of the body. The white blood cells fight infections and cause inflammation.
Diseases of the blood include anemia (low numbers of red blood cells) and leukemias (a malignancy comprising too many of a particular blood cell), among a host of other abnormalities.
The bone marrow is the middle of many of the long bones (femur, tibia, etc) and other bones of the body where the blood cells are actually made. Diseases here include anemia and leukemias, but can also include inadequate production of the blood cells, as well as spread of other cancers, such as breast cancer and prostate cancer.
The lymph nodes are part of the lymphatic system. This system has vessels, similar to capillaries, coursing all through the body. At various junctures in the body, there are lymph nodes, or collections of lymphocytes in a small mass of about 5 mm. These lymphocytes process foreign substances like bacteria, and transform into plasma cells to make antibodies against the foreign substances. These lymphocytes can themselves become cancerous, which are called lymphomas. Lymph nodes can also harbor other malignancies, such as breast cancer, when the cells of this cancer spread out and leave the breast.
Pathology specialists, called hematopathologists are specially trained in identifying and categorizing all of these types of abnormalities. Training to become a hematopathologist takes an additional 1-2 years after basic pathology training. A special examination (board certification) verifies their credentials.
Drs. Saminathan and Arslan are both board certified in hematopathology.