C81-C96: Malignant neoplasms, stated or presumed to be primary, of lymphoid, haematopoietic and related tissue

C82: Follicular lymphoma

Follicular lymphoma is a group of closely related conditions that all pertain to a certain type of cancer originating in the lymphatic system. Each variant of follicular lymphoma shares similar core characteristics – an abnormal, uncontrollable multiplication of cells within the lymph nodes that impact the body's defenses. These cancers are typically slow-growing, referred to as 'indolent' lymphomas, and commonly present with painless, swollen lymph nodes in the neck, armpit, or groin, though less visible symptoms such as fatigue, fever or night sweats can also manifest. The exact cause of follicular lymphoma is unknown, but it's thought to be triggered by certain changes in DNA that occur during a person's lifetime. Disease progression varies from person to person, with some living many years with the disease. There's no known way to prevent this group of conditions, and they can't be transmitted from person to person.