What are tumors of the hematopoietic and lymphoid tissues?

Tumors of the hematopoietic and lymphoid tissues or haematopoietic and lymphoid malignancies are tumors that affect the blood, bone marrow, lymph, and lymphatic system. Haematological malignancies are malignant neoplasms (“cancer”), and they are generally treated by specialists in hematology and/or oncology.