Mantle Cell Lymphoma Health Article

Definition

Mantle cell lymphoma (MCL) is a rare type of non-Hodgkin's lymphoma characterized under the microscope by expansion of the mantle zone area of the lymph node with a homogeneous (structurally similar) population of malignant small lymphoid cells. These cancerous cells have slightly irregular nuclei and very little cytoplasm, and are mixed with newly made normal lymphocytes (white blood cells) that travel from the bone marrow to the lymph nodes and spleen. Unlike normal lymphocytes, they do not mature properly and become cancerous instead.

Description

The body's immune system produces two types of lymphocytes or white blood cells: the B cells which are made in the bone marrow and the T cells which are made in the thymus. Both types of cells are found in the lymph, the clear liquid that bathes tissues and circulates in the lymphatic system. Lymphomas are cancers that occur in this lymphatic system and B-Cell lymphomas—also called non-Hodgkin's lymphomas—include follicular lymphomas, small non-cleaved cell lymphomas (Burkitt's lymphoma), marginal zone lymphomas (MALT lymphomas), small lymphocytic lymphomas, large cell lymphomas and also mantle cell lymphomas.

Mantle cell lymphoma accounts for 5% to 10% of all lymphomas diagnosed and 5% of B-cell lymphomas. There are three subsets of MCL cells: the mantle zone type, the nodular type, and the blastic or blastoid type. These various types often occur together to some degree, and approximately 30% to 40% of diagnoses are of mixed mantle and nodular type. As MCL develops further, the non-cancerous mantle centers also become invaded by cancerous cells. In about 20% of these cases, the cells become larger, and of the blastic (immature) type.

Extensive debates are ongoing concerning the grade of this cancer. European classification used to classify it as a low-grade cancer because it is initially slow-growing, while American classification considered it intermediate based on patients' shorter average survival rate. The combined European-American classification (REAL), is still discussing the status of mantle cell lymphoma. This is due to the mixed nature of MCL cells. Blastic type-MCL seems to be considered as a high-grade cancer because it spreads at about the rate of other lymphomas belonging to that category. The studies currently attempting to describe the precise nature of these cells will be key to any general agreement that is finally reached.

Demographics

Mantle cell lymphoma is rare in persons under the age of 50. It is most often seen in men aged 50-70 years. Out of 1, 000 persons diagnosed with MCL, approximately 33% will be women. This cancer has the shortest average survival of all lymphoma types.

Causes and symptoms

The cause of MCL is unknown. Many of its symptoms are shared by other lymphomas as well and patients generally complain of fatigue, anemia, low grade fevers, night sweats, weight loss, rashes, digestive disturbances, chronic sinus irritation, recurrent infections, sore throat, shortness of breath, muscle and bone aches and edema.

More specific symptoms include spleen enlargement (in about 60% to 80% of cases), particularly with nodular-type MCL. Swollen lymph nodes are an early-stage symptom, even though the general health of the patient is good. Mild anemia is also common. Some patients also report lower back pain, and burning pain in the legs and testicles. As MCL becomes more advanced, the lymph nodes increase in volume, and the general symptoms become more pronounced.

In the end stage of MCL, neurologic symptoms appear, indicating that the MCL has spread to the central nervous system.

Diagnosis

MCL is very similar to several other lymphoma types and special care must be taken with the diagnosis. It should not be made from blood or bone marrow specimens alone. It is believed that immunologic tests are required to make the correct diagnosis. Immunopheno-typing is one such test, it is used to determine what kind of surface molecules are present on cells, and thus, the exact type of lymphoma from a tissue sample. The Lymphoma Research Foundation of America recommends that several opinions be sought from recognized mantle cell experts to confirm the accuracy of the diagnosis.

At the time of diagnosis, mantle cell lymphoma has usually spread into other tissues such as the lymph nodes, spleen, bone marrow (up to 90% of cases), or to Waldeyer's ring (the ring of adenoid, palatine and lingual tonsils at the back of the mouth) or to the gastrointestinal tract. MCL can also spread to the colon, in which case it is diagnosed as multiple lymphomatous polyposis.

Treatment team

Depending on the type of MCL and stage of the cancer, the treatment team may include a radiation oncologist, a medical oncologist, a surgeon and a neurologist.