Pathogenesis
MCL, like most cancers, results from the acquisition of a combination of (non-inherited) genetic mutations in somatic cells. This leads to a clonal expansion of malignant B lymphocytes. The factors that initiate the genetic alterations are typically not identifiable, and usually occur in people with no particular risk factors for lymphoma development. Because it is an acquired genetic disorder, MCL is neither communicable nor inheritable.A defining characteristic of MCL is mutation and overexpression of cyclin D1, a cell cycle gene, that contributes to the abnormal proliferation of the malignant cells. MCL cells may also be resistant to drug-induced apoptosis, making them harder to cure with chemotherapy or radiation. Cells affected by MCL proliferate in a nodular or diffuse pattern with two main cytologic variants, typical or blastic. Typical cases are small to intermediate-sized cells with irregular nuclei. Blastic (aka blastoid) variants have intermediate to large-sized cells with finely dispersed chromatin, and are more aggressive in nature. The tumor cells accumulate in the lymphoid system, including lymph nodes and the spleen, with non-useful cells eventually rendering the system dysfunctional. MCL may also replace normal cells in the bone marrow, which impairs normal blood cell production. Diagnosis
Diagnosis generally requires stained slides of a surgically removed part of a lymph node. Other methods are also commonly used, including cytogenetics and fluorescence in situ hybridization (FISH). Polymerase chain reaction (PCR) and CER3 clonotypic primers are additional methods, but are less often used.The immunophenotype profile consists of CD5+ (in about 80% of cases), CD10-/+, and it is usually CD5+ and CD10-.
Mantle cell lymphoma (MCL) is a type of non-Hodgkins lymphoma (NHL), comprising about 6% of NHL cases. There are only about 15,000 patients presently in the United States with mantle cell lymphoma. It is named for the mantle zone of the lymph nodes. MCL is a subtype of B-cell lymphoma, due to CD5 positive antigen-naive pregerminal center B-cell within the mantle zone that surrounds normal germinal center follicles. MCL cells generally over-express cyclin D1 due to the t(11:14) translocation, a chromosomal translocation in the DNA. Signs and symptoms
At diagnosis, patients typically are in their 60s and present to their physician with advanced disease. About half have B symptoms such as fever, night sweats, or unexplained weight loss (over 10% of body weight). Enlarged lymph nodes (for example, a "bump" on the neck, armpits or groin) or enlargement of the spleen are usually present. Bone marrow, liver and gastrointestinal tract involvement occurs relatively early in the course of the disease. Mantle cell lymphoma has been reported in rare cases to be associated with severe allergic reactions to mosquito bites. These reactions involve extensive allergic reactions to mosquito bites which range from greatly enlarged bite sites that may be painful and involve necrosis to systemic symptoms (e.g. fever, swollen lymph nodes, abdominal pain, and diarrhea), or, in extremely rare cases, to life-threatening anaphylaxis. In several of these cases, the mosquito bite allergy (MBA) reaction occurred prior to the diagnosis of MCL suggesting that MBA can be a manifestation of early-developing mantle cell lymphoma.