Rectal cancer. Light micrograph of a section through the rectum with lymphosarcoma. This cancer is a non-Hodgkin's lymphoma, a malignant tumour (neoplasm) that causes proliferation of lymphocytes (a type of white blood cell). There are three grades of non-Hodgkin's lymphoma. The low grade form has a poor prognosis and results in death within 8 years. Intermediate and high grade forms have a better prognosis and may be cured with chemotherapy. Magnification unknown.