Follicular lymphoma is a form of non-Hodgkin lymphoma (see this term) characterized by a proliferation of B cells whose nodular structure of follicular architecture is preserved. Prevalence of follicular lymphoma is estimated at about 1/3,000. The median age at diagnosis is 60-65 years. The disease is extremely rare in children. Follicular lymphoma is located primarily in the lymph nodes, but can also involve the spleen, bone marrow, peripheral blood and Waldeyer's ring. The skin and central nervous system are affected in rare cases. Symptoms appear at an advanced stage of the disease and can include fever, night sweats and weight loss. At diagnosis, patients usually present with adenopathy and, in 50% of cases, splenomegaly. In 85% of cases, follicular lymphomas are associated with a translocation t(14;18) (q32;q21), which activates the BCL2 gene encoding the BCL2 protein that is essential for some apoptosis processes. Diagnosis is based on histological analysis of the adenopathy, a complete blood count, measurement of lactate dehydrogenase (LDH) and biopsy analysis of a lymph node. Examination using imagery (particularly a chest radiograph) is required. The observation of the translocation t(14;18) by polymerase chain reaction (PCR), in addition to suggested histological results, confirms the diagnosis. Differential diagnoses include chronic lymphocytic B cell leukemia, diffuse large B cell lymphoma, mantle cell lymphoma and MALT lymphoma (see these terms). If the lymphoma is localized it should be treated by radiotherapy. In the case of advanced stage lymphoma, chemotherapy with immuno-chemotherapy should be offered (rituximab combined with CHOP). In cases of chemosensitive relapse, treatment can be intensified. The survival rate at five years is 80-90% and medial survival is approximately 10-12 years.
Last update: March 2010