Concomitant subcutaneous intravascular lymphoma lesions in a patient with cardiac diffuse large B-cell lymphoma: is intravascular lymphoma a distinct clinical entity?

Diffuse large B-cell lymphoma (DLBCL) with significant intravascular invasion. Close resemblance of its clinicopathological features to intravascular large B-cell lymphoma, but not to DLBCL-not otherwise specified

Intravascular large B-cell lymphoma (IVLBCL) is defined by the World Health Organization (WHO) Classification as one type of extranodal large B-cell lymphoma and it is characterized by the selective growth of lymphoma cells within blood vessels with minimal extravascular invasion. According to the criteria, however, several reported cases of IVLBCL with significant extravascular invasion cannot be classified as IVLBCL. The purpose of the present study was to assess the clinicopathological significance of the WHO criteria for IVLBCL. We characterized clinical, histopathological, and immunohistochemical features of 11 patients with extranodal diffuse large B-cell lymphoma (DLBCL) with significant intravascular invasion (DLBCL-IV), and statistically compared their features with those of 11 patients with IVLBCL and 15 patients with extranodal DLBCL with virtually no intravascular invasion (DLBCL-noIV). When compared with the DLBCL-noIV group, the DLBCL-IV group was characterized by significantly higher rates of splenomegaly, hemophagocytosis, advanced stage disease, and CD5 expression; higher average platelet count, serum lactate dehydrogenase level, and serum ferritin level. Progression-free survival was significantly shorter in the DLBCL-IV group than the DLBCL-noIV group. In contrast, there were no significant differences in clinicopathological features between the DLBCL-IV and the IVLBCL groups. Our study suggests that DLBCL-IV should be regarded as IVLBCL-related.

Bone marrow infiltration pattern in patients with intravascular large B-cell lymphoma diagnosed by random skin biopsy

We retrospectively analyzed bone marrow (BM) infiltration pattern in consecutive 30 intravascular large B-cell lymphoma (IVLBCL) patients diagnosed by random skin biopsy (RSB). BM infiltration of lymphoma was observed in 18 patients (60.0%), including five patients with the intrasinusoidal pattern with minimal extravasation, eight patients with the mixed of intrasinusoidal and scattered/interstitial or nodular infiltration, and five patients with the nodular/diffuse pattern. Twelve patients were negative for lymphoma infiltration. BM histology of patients with IVLBCL were diverse and frequently discordant with those of other site of IVLBCL lesions. BM biopsy had a poorer diagnostic performance for detecting intravascular features.