Intravascular Large B-cell Lymphoma Transformed from a Mantle Cell Lymphoma: A Case Report and Literature Review

Intravascular large B-cell lymphoma (IVLBCL) is a rare type of extranodal diffuse large B-cell lymphoma (NHL) characterized by the presence of neoplastic lymphocytes only in the lumina of small vessels and capillaries. Although studies have shown an association of IVLBCL with other lymphomas, its relationship with mantle cell lymphoma has not been reported. Here we report a rare case of a 76 year-old male with intravascular transformation of mantle cell lymphoma in the adrenal glands. Histopathological examination of the adrenal mass biopsy revealed two cell populations within the fibrovascular tissue – a diffuse and infiltrative small lymphoid cell population and an unexpected large neoplastic cell population. Immunohistochemistry (IHC) for the small lymphoid cells are positive for CD5, CD20, and cyclin D1, with the t(11;14)(q13;q32) chromosomal rearrangement on cytogenetic analysis by interphase fluorescence in situ hybridization (FISH), characteristic for mantle cell lymphoma. The large cells are positive for CD5, CD20 and CD79a and negative for cyclin D1 on IHC, demonstrating exclusive localization within small capillaries by CD34 staining, evident of IVLBCL. In addition, FISH analysis revealed that the large cells also have the t(11;14)(q13;q32) mantle cell lymphoma rearrangement. To our knowledge, the present study provides the first reported case of IVLBCL transformation from mantle cell lymphoma and supports the hypothesis that IVLBCL may arise by transformation from other lymphomas.