Primary mediastinal (thymic) large B-cell lymphoma (PMBCL) is an uncommon subtype of non-Hodgkin lymphoma (NHL) that presents with a mediastinal mass and has unique clinicopathological features. Historically, patients with PMBCL were treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy ± involved field radiation. Since a phase II trial, published in April 2013, demonstrated excellent results using dose-adjusted (DA) R-EPOCH (rituximab, etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin), this treatment has gained popularity. We performed a retrospective, multicentre analysis of patients aged ≥18 years with PMBCL since January 2011. Patients were stratified by frontline regimen, R-CHOP versus DA-R-EPOCH. 132 patients were identified from 11 contributing centres (56 R-CHOP and 76 DA-R-EPOCH). The primary outcome was overall survival. Secondary outcomes included progression-free survival, complete response (CR) rate, and rates of treatment-related complications. Demographic characteristics were similar in both groups. DA-R-EPOCH use increased after April 2013 (79% vs. 45%, P < 0·001), and there was less radiation use after DA-R-EPOCH (13% vs. 59%, P < 0·001). While CR rates were higher with DA-R-EPOCH (84% vs. 70%, P = 0·046), these patients were more likely to experience treatment-related toxicities. At 2 years, 89% of R-CHOP patients and 91% of DA-R-EPOCH patients were alive. To our knowledge, this represents the largest series comparing outcomes of R-CHOP to DA-R-EPOCH for PMBCL.

The distinction between plasmablastic lymphoma from plasmablastic myeloma warrants detailed knowledge of clinical, radiological and laboratorial findings. New studies identifying distinctive phenotypical or genetic features are needed to improve the histopathological differentiation of plasmablastic neoplasms.

Plasmablastic lymphoma (PBL) is an aggressive B-cell lymphoma that shows a plasma cell phenotype while lacking expression of B-cell antigens. Multiple myeloma (MM) is an indolent disorder of plasma cells that may similarly show plasmablastic morphology, thus posing a diagnostic challenge. We present the clinical and pathologic findings of a series of plasmablastic neoplasms. A 10-year retrospective search of our files using the word "plasmablastic" yielded 11 cases. These were divided into PBL (n = 6), MM (n = 2) and indeterminate (n = 3), using available data.

Langerhans cell histiocytosis (LCH) is a rare clonal proliferative disorder most commonly involving the bone and skin; however, it can arise in many other locations. It is predominantly a pediatric disease, but adult cases occur. Here, we present a case of adult-onset cutaneous LCH with systemic symptoms, believed to represent disseminated LCH. Further evaluation, however, revealed concomitant bone marrow involvement by a small B-cell lymphoma. An association between B-cell lymphoma and cutaneous LCH has only rarely been previously reported. This report adds to the growing body of literature, however, on associations of cutaneous LCH with hematologic malignancies, and it illustrates the need for a complete systemic evaluation including a bone marrow biopsy in suspected cases of disseminated LCH.