The indolent non-Hodgkin's lymphomas (NHLs) represent approximately one third of all malignant lymphomas (1,2); most are of B-cell origin. Follicular lymphoma (FL) is the most common indolent lymphoma. Other indolent B-cell lymphomas include small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL), the marginal zone B-cell lymphomas (MZLs) (extranodal, nodal, and splenic), and lymphoplasmacytic lymphoma (LPL), most cases of which are more specifically classified as Waldenström macroglobulinemia (Table 7-1) (2). Mantle cell lymphoma can morphologically resemble indolent B-cell lymphomas, but it is clinically more aggressive and therefore is not covered in this chapter. Indolent T-cell NHLs, such as mycosis fungoides, are also not covered in this chapter.
Table 7–1. Indolent Lymphomas |Favorite Table|Download (.pdf)
Table 7–1. Indolent Lymphomas
Small lymphocytic lymphoma/chronic lymphocytic leukemia
Extranodal marginal zone B-cell lymphoma (MALT lymphoma)
Splenic B-cell marginal zone lymphoma
Nodal marginal zone lymphoma
Lymphoplasmacytic lymphoma (including Waldenström macroglobulinemia)
|Age||Mostly a disease of older adults (usually over the age of 40 years)|
|Extent of disease||Often disseminated (except MALT lymphoma), with >80% having stage III-IV disease. Bone marrow involvement common|
|Natural history||Low proliferation fraction. Slow-growing; may have a waxing and waning course. Patients typically survive for many years. Transformation to large cell lymphoma can occur.|
|Curability||Although current therapy such as radiotherapy or chemotherapy can often control the disease, it usually fails to eradicate the tumor except for early-stage disease (including MALT lymphoma). This is reflected in a continuous downward slope of relapse-free survival curves for patients with these lymphomas.|
FL represents 22% of all NHLs (1) and 80% of indolent B-cell lymphomas. FL occurs almost exclusively in adults, with an equal frequency in men and women. FL patients typically have a relatively long survival, with a median of 8 to 10 years in the pre-rituximab era (2–4). Outcomes are improving in recent years (5–7).
Patients with FL most often present with asymptomatic lymphadenopathy (1–4). Constitutional symptoms such as fever, drenching night sweats, and significant weight loss occur in approximately 15% of patients. Patients may have symptoms related to lymph node enlargement, especially when there are bulky masses in the retroperitoneum. Other symptoms can include fatigue and, occasionally, end-organ consequences such as obstructive uropathy or bone marrow compromise. Central nervous system (CNS) disease is rare. Urgent situations, such as the superior vena cava syndrome or spinal cord compression are rare, in part related to the usual slow pace of growth of lymphadenopathy in FL. Spontaneous regression of lymphadenopathy can occur in FL. Such regressions, however, are usually partial and are typically short-lived. The potential of FL to wax and wane provides one of several clues that suggest that the host immune system can play an important role in the disease course in FL. Consequently, FL has been a ...