The U.S. Food and Drug Administration (FDA) is informing the public that it continues to receive reports of a rare cancer of white blood cells (known as h epatosplenic T-Cell lymphoma or HSTCL ), primarily in adolescents and young adults being treated for Crohn’s disease and ulcerative colitis with medicines known as tumor necrosis factor ( TNF ) blockers, as well as with azathioprine , and/or mercaptopurine . Crohn's disease and ulcerative colitis cause inflammation of the digestive system. Common symptoms are pain in the abdomen, cramps, and diarrhea. Bleeding from the rectum, wei...