Rare lymphocytic leukemias

The World Health Organization (WHO) uses the criteria below to classify a cancer that starts in lymphocytes as a lymphoma, a lymphocytic leukemia or a leukemia/lymphoma. They differ in where the abnormal lymphocytes are found.

• If the abnormal lymphocytes are found mainly in the blood or bone marrow, it is considered leukemia.
• If tumours develop in the lymph nodes or other organs, it is considered a lymphoma.
• If the disease is found in the blood or bone marrow and as a tumour, it is considered a leukemia/lymphoma.

Find out more about the following rare types of cancer that start from lymphocytes:

• prolymphocytic leukemia (PLL)
• T-cell large granular lymphocytic leukemia (TLGL)
• aggressive NK-cell leukemia (ANKL)
• adult T-cell leukemia/lymphoma (ATLL)
• Sezary syndrome (the leukemia type of cutaneous T-cell lymphoma)