Solitary plasmacytoma refers to a neoplastic, clonal proliferation of plasma cells forming a single mass. They are divided based on their origin site; solitary bone plasmacytomas originate from the bones, and extramedullary plasmacytomas represent extraosseous tumors. These are rare tumors but carry a risk of transforming to multiple myeloma; thus, optimal management and meticulous follow-up are needed. Their rarity poses a major challenge in conducting large-scale clinical trials, leaving important gaps in evidence regarding best practices. Newer imaging techniques have improved the quality of staging, management decisions, and outcomes. Radiation still has a significant role in treatment algorithms, and adjuvant chemotherapy is gaining more importance; trials are underway in this area. Follow-up should contain biochemical tests as the proposed response definition criteria. We aimed to review the key studies and guidelines in this paper.

Background: Mediastinal gray zone lymphoma (MGZL) is a rare B-cell lymphoma which shares clinicopathologic and molecular features between primary mediastinal B-cell lymphoma (PMBL) and classical Hodgkin lymphoma (CHL). Although included as provisional disease entity back in 2008 WHO classification after initial description in 1998, the concept of MGZL has since evolved, with latest WHO-HEMA5 and ICC limiting the entity to EBV-negative mediastinal lesion. Methods: This review summarizes the historical evolution, epidemiology, clinicopathologic characteristics, immunophenotypic and genetic features, diagnostic challenges, and therapeutic strategies for MGZL. Data from retrospective series, prospective cohorts, and recent molecular studies are synthesized to provide a comprehensive perspective. Results: MGZL generally affects young adults, especially males, and presents with bulky mediastinal disease. Transitional morphology, pleomorphic Reed–Sternberg–like cells, and variable B-cell and activation markers make its diagnosis challenging. Molecular studies have shown that they share changes with PMBL and CHL such as 9p24. 1 (JAK2/PD-L1/PD-L2); however, specific alterations, including HOXA5 hypomethylation and MYC gains, argue for its designation as a separate entity. Therapeutically, DA-EPOCH-R is one of the most effective regimens, but prognosis is still worse than PMBL or CHL, 5-year OS ~40–60%. Salvage chemotherapy and autologous transplantation are frequently necessary for relapsed/refractory disease. Novel therapies, especially brentuximab vedotin and PD-1 inhibitors, appear to be effective, especially in combination. Conclusion: MGZL continues to be a diagnostically challenging, and therapeutically complex lymphoma with an inferior prognosis compared to related entities. Advancements in molecular profiling and immunotherapy suggest the promise of personalized therapy. Yet, prospective clinical trials and international cooperation are urgently needed to develop guidelines for therapy of this rare lymphoma.

Background/Objectives: Allogeneic hematopoietic stem cell transplantation is associated with increased cardiovascular risk driven by endothelial dysfunction, chronic inflammation, and treatment-related metabolic disturbances, including dyslipidemia. In the contemporary era of post-transplant cyclophosphamide-based prophylaxis, the prognostic significance of dyslipidemia—particularly as assessed by non-HDL cholesterol—remains unclear. In this study, we aimed to compare the engraftment days, graft-versus-host disease (GVHD) development, relapse, overall survival rates, and cardiovascular mortality in patients using myeloablative/reduced intensity conditioning regimens with post-transplant cyclophosphamide (PTCy) 50 mg/kg/day for 2 days in patients with acute leukemias. Methods: A total of 95 adult patients with acute leukemias were included in their first remission who underwent matched sibling donor transplantation with PTCy (50 mg/kg on days +3 and +4). Patients were stratified according to pre-transplant non-HDL-C levels (<160 mg/dL vs. ≥160 mg/dL). Matched related donors were selected for the patients. All patients received either myeloablative or reduced-intensity conditioning based on EBMT criteria, with fludarabine-based combinations including busulfan, treosulfan, or TBI, along with ATLG administered at a total dose of 15 mg/kg. Peripheral blood stem cells were used for all transplants, and GVHD prophylaxis consisted of cyclosporine. Results: Platelet (median 13 vs. 14 days) and neutrophil (median 14 vs. 15 days) engraftment times and veno-occlusive disease (VOD) rates were comparable across groups (all p > 0.05); cumulative incidences of grade II–IV aGVHD at +100 days, grade III–IV aGVHD at +100 days, and moderate-severe cGVHD at 1 year, relapse-free survival, and non-relapse mortality at 1 year were comparable in two cohorts (all p > 0.05). GVHD-free/relapse-free survival (GRFS) at 1 year was also comparable across groups (p = 0.15). Median GRFS was 150 (95% CI: 120–330) days and 270 (95% CI: 154-not reached) days, respectively [HR was 0.68 (0.40–1.15), p = 0.15; GRFS at 1 year was 66.6% vs. 52.0%, respectively]. The groups were also comparable in terms of overall survival (OS). Follow-up ranged from 0.5 to 108 months, and median follow-up was 60 months in two cohorts. Median OS was not reached in non-HDL-C < 160 (95% CI: 70 months–not reached) and 67 months in non-HDL-C ≥ 160 groups (95% CI: 13 months–not reached) (Log rank = 0.21). No cardiovascular death events occurred during the follow-up period. Conclusions: In this homogeneous matched sibling donor transplant cohort with extended follow-up and uniform administration of post-transplant cyclophosphamide, cyclosporine-based GVHD prophylaxis, and anti-thymocyte lymphoglobulin (ATLG), pre-existing dyslipidemia was not associated with an adverse impact on GRFS, NRM, PFS, CMV reactivation, OS or long-term cardiovascular mortality.