Definition of Hodgkin's lymphoma:

Hodgkin's lymphoma is a malignancy (cancer) of lymph tissue found in the lymph nodes, spleen, liver, and bone marrow.

Causes, incidence, and risk factors:

The first sign of this cancer is often an enlarged lymph node which appears without a known cause. The disease can spread to nearby lymph nodes and later may spread to the lungs, liver, or bone marrow.

The cause is not known. Hodgkin's lymphoma is most common among people 15 to 35 and 50 to 70 years old.