Disease, Hodgkin's (adult): A type of lymphoma (cancer of the lymphatic system). The most common symptom is painless swelling of the lymph nodes in the neck, underarm, or groin. Hodgkin's disease is diagnosed when abnormal tissue is detected by a pathologist after a biopsy of an enlarged lymph node. Treatment usually includes radiation therapy or chemotherapy. Regular follow-up examinations are important after treatment. Patients treated for Hodgkin disease have an increased risk of developing other types of cancer later in life, especially leukemia.