Lymphoma, non-Hodgkin: Malignant tumors that arise in the lymphatic system. There are several subtypes of cancer classified as non-Hodgkin's lymphoma. All originate in and spread via the lymphatic system. Symptoms depend on the location of the tumor, but can include swollen, but not painful, lymph nodes; gastric distress; skin problems; night sweats; unexplained weight loss; itching; and fever. Diagnosis is by biopsy. Treatment may be chemotherapy, radiation, stem cell transplant, or other medications including monoclonal antibodies- alone, or with chemotherapy or even coupled to radioactive materials, depending on the age of the patient and type of tumor. Abbreviated NHL.