Intravascular large B-cell lymphoma (IVLBCL) is a rare type of extranodal large B-cell lymphoma characterized by the selective growth of lymphoma cells within the lumina of vessels, particularly capillaries, with exception of larger arteries and veins.
Angiotropic large cell lymphoma.
This tumor occurs in adults (median, 67 years; range, 13-85 years) and with a M:F ratio of 1.1 :1. The frequency and clinical presentation differ according to the geographical origin of the patients between the West and the Far East
Sites of involvement
This lymphoma is usually widely disseminated in extranodal sites including bone marrow (BM) and may present virtually in any organ. However, lymph nodes are usually spared.
Two major patterns of clinical presentation have been recognized, a Western form characterized by symptoms related to the main organ involved, predominantly neurological or cutaneous, and an Asian variant in which the patients present with multiorgan failure, hepatosplenomegaly, pancytopenia and haemophagocytic syndrome
These presentations are seen more frequently, although not exclusively, in Western and Far East countries, respectively, B symptoms are very common (55-76% of patients) in both types of presentation. An isolated cutaneous variant has been identified invariably in Western females; it characterized by limitation of the tumor to the skin and is associated with a better prognosis. Conventional staging procedures are generally associated with high proportion of false negatives because of the lack of detectable tumour masses.
The neoplastic lymphoid cells are mainly lodged in the lumina of small or intermediate vessels in many organs. Fibrin thrombi. hemorrhage and necrosis may be observed in some cases. The tumour cells are large with prominent nucleoli and frequent mitotic figures. Rare cases have cells with anaplastic features or smaller size. Minimal extravascular location of neoplastic cells may be seen. Sinusoidal involvement occurs in the liver, spleen and BM. Malignant cells are occasionally detected in peripheral blood.
Tumour cells express B-cell-associated antigens. CD5 and CD10 coexpression is seen in 38% and 13% of the cases, respectively. Almost all of CD10-negative cases are IRF4/MUMI positive. Anecdotal cases of intravascular T-cell NK-cell lymphoma have been reported, but they should be considered a different entity.
The intravascular growth pattern has been hypothesized to be secondary to a defect in homing receptors on the neoplastic cells, such as the lack of CD29 (b1 integrin) and CD54 (CAM-1) adhesion b-molecules.
Immunoglobulin genes are clonally rearranged. Karyotypic abnormalities have been described but too few cases have been studied.
Postulated normal counterpart Transformed peripheral B-cell.
Prognosis and predictive factors
This is an aggressive lymphoma which responds poorly to chemotherapy. The poor prognosis reflects in part frequent delays in diagnosis due to the protean presentation. Neither clinical types of presentation nor clinical parameters predicts patient survival, with the exception of the better prognosis for the cases with disease limited to the skin.