What type of cancer is lymphoma and where does it arise?

• A. Malignancy of plasma cells in bone marrow.
• B. Malignancy of lymphatic system involving lymph nodes and lymphoid tissues.
• C. Malignancy of melanocytes in skin.
• D. Myeloproliferative disorder with Philadelphia chromosome.

Answer: (B)

Lymphoma is cancer of the lymphatic system, arising in lymph nodes and other lymphoid tissues such as the spleen, tonsils, or thymus. This distinguishes it from cancers of other tissues: malignancy of plasma cells in bone marrow describes multiple myeloma, a plasma cell cancer not centered in the lymphatic system; melanoma comes from melanocytes in the skin; and a Philadelphia chromosome–positive myeloproliferative disorder refers to diseases like chronic myeloid leukemia, not lymphoma. Therefore, lymphoma is cancer of the lymphatic system that originates in lymph nodes and related lymphoid tissues.