Intravascular B-large cell lymphoma: an unexpected diagnosis of an incidental adrenal mass

Cutaneous Intravascular Hematolymphoid Entities: A Review

Intravascular lymphomas are rare disease conditions that exhibit neoplastic lymphoid cells that are confined mainly to the lumens of small capillaries and medium-sized vessels. The majority of the intravascular lymphomas are of B-cell origin, but they can include NK/T-cell and CD30+ immunophenotypes. In the histologic differential diagnosis are benign proliferations such as intralymphatic histiocytosis and intravascular atypical CD30+ T-cell proliferation. In this review, we discuss the clinical, histopathologic, and molecular findings of intravascular B-cell lymphoma, intravascular NK/T-cell lymphoma, intralymphatic histiocytosis, and benign atypical intravascular CD30+ T-cell proliferation.

Intravascular Large B-Cell Lymphoma Genomic Profile Is Characterized by Alterations in Genes Regulating NF-κB and Immune Checkpoints

Intravascular large B-cell lymphoma (IVLBCL) is an uncommon lymphoma with an aggressive clinical course characterized by selective growth of tumor cells within the vessels. Its pathogenesis is still uncertain and there is little information on the underlying genomic alterations. In this study, we performed a clinicopathologic and next-generation sequencing analysis of 15 cases of IVLBCL using a custom panel for the detection of alterations in 68 recurrently mutated genes in B-cell lymphomagenesis. Six patients had evidence of hemophagocytic syndrome. Four patients presented concomitantly a solid malignancy. Tumor cells outside the vessels were observed in 7 cases, 2 with an overt diffuse large B-cell cell lymphoma. In 4 samples, tumor cells infiltrated lymphatic vessel in addition to blood capillaries. Programmed death-ligand 1 (PD-L1) was positive in tumor cells in 4 of 11 evaluable samples and in macrophages intermingled with tumor cells in 8. PD-L1 copy number gains were identified in a higher proportion of cases expressing PD-L1 than in negative tumors. The most frequently mutated gene was PIM1 (9/15, 60%), followed by MYD88L265P and CD79B (8/15, 53% each). In 6 cases, MYD88L265P and CD79B mutations were detected concomitantly. We also identified recurrent mutations in IRF4 , TMEM30A , BTG2 , and ETV6 loci (4/15, 27% each) and novel driver mutations in NOTCH2 , CCND3 , and GNA13 , and an IRF4 translocation in 1 case each. The mutational profile was similar in patients with and without evidence of hemophagocytic syndrome and in cases with or without dissemination of tumor cells outside the vessels. Our results confirm the relevance of mutations in B-cell receptor/nuclear factor-κB signaling and immune escape pathways in IVLBCL and identify novel driver alterations. The similar mutational profile in tumors with extravascular dissemination suggests that these cases may also be considered in the spectrum of IVLBCL.

Case Report: Intravascular Large B-Cell Lymphoma: A Clinicopathologic Study of Four Cases With Review of Additional 331 Cases in the Literature

Intravascular large B-cell lymphoma (IVLBCL) is a rare and highly malignant non-Hodgkin B-cell lymphoma with uncommon clinical presentation and poor prognosis. The diagnostic pitfall of IVLBCL is mainly due to the fact that subtle histological changes could be easily overlooked, in addition to its rare occurrence, non-specific and variable clinical presentations, and the absence of significant mass lesions. The purpose of this study is to further explore the clinicopathologic and molecular features of IVLBCL to ensure an accurate diagnosis of this entity. Here, we retrospectively present the data of the four new cases and the literature cases. The age ranged from 23 to 92, with a medium age of 67 and a male-to-female ratio of 1:1. The clinical manifestations are extremely variable, including fever, night sweats, weight loss, anemia, thrombocytopenia, unexplained hypoxemia, impaired consciousness, and skin lesions, as well as the extremely low levels of serum albumin, high levels of serum lactate dehydrogenase (LDH), soluble interleukin-2 receptor (sIL2R), and ferritin. Morphologically, 99.9% of cases showed a selective growth pattern with large, atypical lymphocytes within the lumen of small blood vessels. In addition, vast majority of cases were positive for CD20, CD79a, PAX5, MUM1, and BCL6, and a subset of cases expressed BCL2 and CD5, whereas CD3 and CD10 were typically negative. Ki-67 proliferative index ranged from 20% to 100%. To sum up, we have conducted comprehensive case reports, to the best of our knowledge, this is the largest reported cohort of IVLBCL cases. Comprehensive assessments and more IVLBCL cases are required for early diagnosis and prompt treatment.

Intravascular Large B-Cell Lymphoma

CONTEXT.—

Intravascular large B-cell lymphoma (IVLBCL) is a rare hematopathologic entity, posing both a clinical and histologic challenge for diagnosis. Numerous pitfalls can hinder making the diagnosis.

OBJECTIVE.—

To summarize recent developments in literature pertaining to IVLBCL and point out key pitfalls pathologists should be prepared to encounter.

DATA SOURCES.—

Literature review via PubMed search and hospital (Darnall Medical Library) resources.

CONCLUSIONS.—

The 3 primary pitfalls of IVLBCL include masking of IVLBCL, mimicry by IVLBCL, and mimicry of IVLBCL. These scenarios illustrate the importance of histologic pattern recognition and subsequent usage of immunohistochemistry, especially in context of a clinical history that may be noncharacteristic.