Ji, Yuan

Abstract Objective Rare large B-cell lymphomas (LBCLs) present with concurrent or subsequent lymphomatous effusion (solid-effusion LBCL, SE-LBCL), which may have an inferior prognosis compared with their noneffusion counterpart. In addition, the relationship between SE-LBCL and human herpesvirus 8–negative effusion-based LBCL (EB-LBCL) remains unclear. Methods We collected 141 cases of SE-LBCL and a control cohort of 101 cases of stage IV solid-only LBCL. The clinicopathologic features were analyzed and compared between SE-LBCL and solid-only LBCL. Results Patients with SE-LBCL had a median age of 67 years with a male-to-female ratio of 1.3:1. Eighty-six patients had concurrent solid lymphoma and lymphomatous effusion, whereas 55 developed lymphomatous effusion subsequently. Most cases involved the pleural cavities (79%, 112/141), followed by the peritoneal (21%, 29/141) and pericardial (11%, 16/141) cavities. BCL6, CD10, and MUM1 were expressed in 77% (90/117), 46% (60/130), and 61% (58/95) of cases, respectively, and 58% (71/123) were subclassified into the germinal center B-cell (GCB) subtype. Rearrangements of BCL2, BCL6, and MYC were detected in 42% (31/73), 35% (22/63), and 40% (35/88), respectively, and 22% (19/87) had both MYC and BCL2 rearrangements. The patients with SE-LBCL had a dismal prognosis, with a median survival of 5.7 months, which was significantly worse than solid-only LBCL (147.5 months; P < .0001). Conclusions The pathologic features of SE-LBCL were similar to those of solid-only LBCL but distinct from those of EB-LBCL; in particular, lymphomatous effusion was an independently adverse prognostic factor in LBCL. Our study underscores the need for surveillance of lymphomatous effusion during LBCL staging and development of effective therapeutic regimens for SE-LBCL.

Abstract The dismal outcome of acute leukemia undergoing immunophenotype-switch, compounded by the increased incidence in the era of immunotherapy, highlights the need for in-depth systemic studies. We investigated the clinicopathological, cytogenetic, and molecular features of 33 patients experiencing switch between acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). The median duration from the primary diagnosis to lineage switch was 7.8 months, with the subsequent median survival being < 3 months. The majority experienced a transition from B-ALL to AML. The AML cases demonstrated a spectrum of differentiation, ranging from minimal to erythroid, with monocytic being the most common. Cytogenetic analysis revealed 11q23/KMT2A fusions as the most recurrent abnormalities (n = 18); also observed were complex karyotype, 7/7q-, 9p-/CDKN2A deletion, t(5;14)/TCLX3::BCL11b, t(8;9)/PCM1::JAK2, t(9;22)/BCR::ABL1, and t(12;19)/TCF3::ZNF384. Remarkably, in 60% of patients lacking KMT2A fusions, a chronic myeloid neoplasm was observed preceding the first leukemia. In contrast, no prior hematological malignancies were observed in KMT2A cases. Deep mutational profiling reinforced the inherent clonal relationship between the initial and subsequent leukemias, evident from the overlapping mutational signatures. The presence of distinct additional mutations across the two phases supports the long-standing theory of lineage switch emerging via divergent evolution of a multipotential progenitor.

AbstractObjectivesT-cell prolymphocytic leukemia (T-PLL) is a rare mature T-cell leukemia usually characterized by inv(14)(q11.2q32)/t(14;14)(q11.2;q32). In this study, we aimed to investigate the clinicopathologic features and molecular profile of T-PLL associated with t(X;14)(q28;q11.2).MethodsThe study group included 10 women and 5 men with a median age of 64 years. All 15 patients had a diagnosis of T-PLL with t(X;14)(q28;q11.2).ResultsAll 15 patients had lymphocytosis at initial diagnosis. Morphologically, the leukemic cells had features of prolymphocytes in 11 patients, small cell variant in 3, and cerebriform variant in 1. All 15 patients had hypercellular bone marrow with an interstitial infiltrate in 12 (80%) cases. By flow cytometry, the leukemic cells were surface CD3+/CD5+/CD7+/CD26+/CD52+/TCR α/β+ in 15 (100%) cases, CD2+ in 14 (93%) cases, CD4+/CD8+ in 8 (53%) cases, CD4+/CD8– in 6 (40%) cases, and CD4–/CD8 + in 1 (7%) case. At the cytogenetic level, complex karyotypes with t(X;14)(q28;q11.2) were seen in all 15 patients assessed. Mutational analysis showed mutations of JAK3 in 5 of 6 and STAT5B p.N642H in 2 of 6 patients. Patients received variable treatments, including 12 with alemtuzumab. After a median follow-up of 17.2 months, 8 of 15 (53%) patients died.ConclusionsT-PLL with t(X;14)(q28;q11.2) frequently shows a complex karyotype and mutations involving JAK/STAT pathway, and it is an aggressive disease with a poor outcome.

Context.— Plasmablastic lymphoma (PBL) is a rare aggressive lymphoma, usually positive for CD138 and frequently occurring in the oral cavity of human immunodeficiency virus (HIV) patients. Up to 10% of cases are negative for CD138 and diagnostically very challenging. Objective.— To investigate the appropriate approach to diagnose CD138− plasmablastic lymphoma and avoid misdiagnosis. Design.— We studied 21 cases of CD138− PBL from multiple large institutes in the United States and 21 cases from the literature. Results.— CD138− PBLs were positive for different B/plasma cell markers at various percentages: MUM1 (94.4%; 34 of 36), OCT2 (70.6%; 12 of 17), immunoglobulin light chains (68.8%; 22 of 32), CD38 (68.4%; 13 of 19), CD79a (34.2%; 13 of 38), and PAX5 (15.6%; 5 of 32), suggesting that MUM1, OCT2, immunoglobulin light chains, and CD38 are useful markers to help establish the lineage. A total of 83% of cases (30 of 36) were extraoral lesions. Extraoral lesions showed much lower Epstein-Barr virus (EBV) infection rates (16 of 30; 53.3%) and had worse prognosis. MYC was positive in 80% (8 of 10) of EBV+ cases and 40% (2 of 5) EBV− cases, indicating the importance of MYC in pathogenesis, especially in EBV+ cases. Conclusions.— Our study emphasizes that CD138− PBLs tend to be extraoral lesions, with much lower EBV infection rates, and diagnostically very challenging. Accurate diagnosis requires a thorough investigation and workup by using appropriate markers.

Composite classic Hodgkin lymphoma and follicular lymphoma (CHLFL) is a rare and poorly characterized entity. Herein, we report the clinicopathologic features of 22 cases of CHLFL from 3 institutions and we assess 27 additional cases reported in the literature. In our cohort (n=22), patients with CHLFL had a median age of 61 years and an equal male to female incidence. Most cases (95%) arose de novo with the remaining patients having a history of non-Hodgkin lymphoma. CHLFL always involved lymph nodes (100%) and most cases (95%) revealed 2 distinct areas separately diagnostic for CHL and FL. The CHL component represented a variable proportion of the overall neoplasm (5% to 90%) and was either mixed cellularity (82%) or nodular sclerosis (18%) type. The Hodgkin/Reed-Sternberg cells expressed CD30 (100%), PAX5 (100%), CD15 (62%), BCL6 (47%), BCL2 (29%), and EBER (25%), in a polymorphous inflammatory background typical of CHL. The FL component was low-grade in 55%, grade 3A in 36%, and grade 3B in 9% of cases. All 3 cases investigated by cytogenetic methods for a clonal relationship between the CHL and FL components were clonally related. These clinicopathologic features of our cohort are similar to those of cases reported in the literature. The 5-year overall survival in combined patients with CHLFL (n=49) was 48%, comparable to CHL but worse than FL in the elderly. In summary, CHLFL is a rare entity that most often occurs in older adults, involves lymph nodes, and most commonly presents de novo. In the small number of cases assessed, the CHL and FL components are usually clonally related suggesting that the CHL and FL components may share a common progenitor B-cell, likely a mutated germinal center B-cell.