Classical Hodgkin Lymphoma is one of the most curable neoplasms worldwide, particularly among young adults. Significant advances have been made to maximize treatment efficacy and minimize acute and long-term toxicities, including infertility, cardiovascular complications and secondary primary malignancies. Pretreatment prognostic stratification and interim PET response are the cornerstones of personalized treatment strategies. Circulating tumor cell-free DNA represents an investigational tool for genotyping Hodgkin Lymphoma at diagnosis and monitoring treatment response. An abbreviated course of polychemotherapy followed by involved-site/involved nodal radiotherapy continues to be the gold standard in early-stage diseases, while polychemotherapy remains the mainstay for the treatment of advanced-stage disease with or without the incorporation of novel agents, such as the anti-CD30 antibody-drug conjugate brentuximab-vedotin (BV) or the anti-PD1 checkpoint inhibitors (CPI) nivolumab and pembrolizumab. In elderly patients, treatment requires careful adaptation to minimize acute toxicities, often reducing the chemotherapy load or incorporating new targeted therapies. Although consolidation with autologous stem cell transplantation (ASCT) after salvage chemotherapy remains the standard approach in patients with chemosensitive relapsed/refractory cHL, significant improvements in response rate and duration have been achieved when BV and CPI are integrated into salvage regimens prior to ASCT or as post-transplant maintenance. Both classes of drugs are also approved as monotherapy in patients who are transplant-ineligible or have refractory/relapsed disease. Novel therapeutic approaches, including anti-CD30 CAR-T cells and the combination of the anti-CD30/CD16A bispecific antibody AFM13 with preactivated allogeneic cord blood-derived NK cells, are under investigation for patients who have failed the currently approved treatment options.

Elderly LBCL patients have unfavorable clinical and biological features, leading to higher relapse rates. While CD19 CAR-T therapy offers a curative option in second-line, access remains limited by clinical criteria in pts aged ≥ 65 years. In our real-world study, we evaluated 232 LBCL pts ≥ 65 years focusing on first line outcomes and potential CAR-T eligibility. Sixty-four patients progressed or relapsed. Applying AIFA criteria, only 9/37 (24

Background: Patients with low tumour burden follicular lymphoma (FL) are managed with an initial watchful waiting (WW) approach. The way to better predict the time-to-treatment (TTT) is still under investigation for its possible clinical impact. This study explored whether radiomic features extracted from baseline 18F-FDG PET/CT could predict TTT in FL patients on WW. Methods: Thirty-eight patients on initial WW (grade 1–3a) were retrospectively included from 2010 to 2019. Eighty-one PET/CT morphological and first-level intensity radiomic features were extracted from the total metabolic tumour burden (TMTV), the lesion having the highest SUVmax and a reference volume-of-interest placed on the healthy liver. Models using linear regression (LR) and support vector machine (SVM) were constructed to assess the feasibility of using radiomic features to predict TTT. A leave-one-out cross-validation approach was used to assess the performance. Results: For LR models, we found a root-mean-squared error of 29.4, 28.6, 26.4 and 26.8 and an R2 of 0.03, 0.08, 0.21 and 0.20, respectively, incrementing the features from one to four. Accordingly, the best model included three features: the liver minimum SUV value, the liver SUV skewness and the sum of squared SUV values in the TMTV. For SVM models, accuracies of 0.79, 0.63, 0.76 and 0.68 and areas under the curve of 0.80, 0.72, 0.77 and 0.63 were found, respectively, incrementing the features from one to four. The best performing model used one feature, namely the median value of the lesion containing the SUVmax value. Conclusions: The baseline PET/CT radiomic approach has the potential to predict TTT in FL patients on WW. Integrating radiomics with clinical parameters could further aid in patient stratification.

Background and Clinical Significance: This case report describes a 46-year-old male with no prior comorbidities who developed progressive neurological symptoms—ataxia and diplopia—shortly after the second Comirnaty (Pfizer-BioNTech) COVID-19 vaccine dose. The aim is to highlight the diagnostic challenges of central nervous system-dominant hemophagocytic lymphohistiocytosis (HLH) and its overlap with neuroinflammatory disorders. Case Presentation: Initial MRI showed demyelinating lesions in the brain and spinal cord, suggesting acute disseminated encephalomyelitis (ADEM). The patient had only transient improvement with corticosteroids and then multiple relapses with expanding CNS lesions despite cyclophosphamide, plasmapheresis, and rituximab. After 27 months, systemic features appeared, including fever, cytopenias, elevated inflammatory markers, and splenomegaly. Bone marrow analysis revealed hemophagocytosis, fulfilling HLH-2004 criteria, with an H-score of 200 supporting secondary HLH. Given consanguinity and persistent immune activation, next-generation sequencing identified two homozygous PRF1 variants—one pathogenic (p.Arg232His) and one of uncertain significance (p.Ala91Val)—consistent with autosomal recessive familial type 2 HLH. The patient underwent matched unrelated donor hematopoietic stem cell transplantation (HSCT) 11 months after HLH diagnosis, achieving initial stabilization, but ultimately died from infectious complications in March 2025 without evidence of HLH relapse. Conclusions: This case illustrates an atypical adult-onset presentation of familial HLH manifesting primarily with recurrent neuroinflammatory symptoms that initially mimicked ADEM. The diagnostic delay reflects the challenge of recognizing CNS-dominant HLH, especially in adults and in the absence of early systemic features. The identification of biallelic PRF1 variants confirmed an underlying genetic predisposition. This is the first reported case of adult-onset familial HLH presenting predominantly with neurological symptoms following COVID-19 vaccination. The case emphasizes the need to consider genetic forms of HLH in relapsing neuroinflammatory disorders and raises the hypothesis that vaccination may unmask subclinical immune dysregulation in genetically susceptible individuals

Since the introduction of rituximab in the late 1990s, significant progress has been made in advancing targeted therapies for B cell lymphomas, improving patients’ chance of being cured and clinicians’ therapeutic armamentarium. A better understanding of disease biology and pathogenic pathways, coupled with refinements in immunophenotypic and molecular diagnostics, have been instrumental in these achievements. While traditional chemotherapy remains fundamental in most cases, concerns surrounding chemorefractoriness and cumulative toxicities, particularly the depletion of the hemopoietic reserve, underscore the imperative for personalized treatment approaches. Integrating targeted agents, notably monoclonal antibodies, alongside chemotherapy has yielded heightened response rates and prolonged survival. A notable paradigm shift is underway with innovative-targeted therapies replacing cytotoxic drugs, challenging conventional salvage strategies like stem cell transplantation. This review examines the landscape of emerging targets for lymphoma cells and explores innovative therapies for diffuse large B cell lymphoma (DLBCL). From Chimeric Antigen Receptor-T cells to more potent monoclonal antibodies, antibody–drug conjugates, bispecific antibodies, checkpoint inhibitors, and small molecules targeting intracellular pathways, each modality offers promising avenues for therapeutic advancement. This review aims to furnish insights into their potential implications for the future of DLBCL treatment strategies.

Vitamin B12 deficiency is a common condition that causes a variety of disorders ranging from the development of megaloblastic anemia to the building up of neurological damage. Historically one of the leading causes of B12 deficiency appears to be secondary to malabsorption in part caused by the development of atrophic gastritis in pernicious anemia. More recently B12 deficiency could also depend on dietary restrictions. Cobalamin deficiency also appears to be closely related to folate metabolism, causing a reduction in methionine synthase activity. This results in the accumulation of 5-methyltetrahydrofolate (5-MTHF) and defective DNA synthesis. It has been hypothesized that reduced activity of the enzyme methylene-tetrahydrofolate reductase (MTHFR) could reduce the production of 5-MTHF, thereby shifting folate metabolism to thymidylate synthesis and promoting proper DNA synthesis. Our aim was to investigate the role of the C677T and A1298C MTHFR gene polymorphisms, which are associated with reduced enzyme activity, in predisposing to the development of anemia, neurological symptoms, and atrophic gastritis in a population of 105 consecutive Italian patients with cobalamin deficiency. We found statistically significant correlations between the degree of anemia and thrombocytopenia and the C677T MTHFR polymorphism, while hemoglobin levels alone significantly correlated with A1298C polymorphism, contradicting the potential protective role of these polymorphisms. Furthermore, in patients with atrophic gastritis, we found an association between the absence of parietal cell antibodies and the presence of the C677T polymorphism in homozygosity. Our results suggest a role for MTHFR enzyme activity in the severity of hematologic manifestations of vitamin B12 deficiency and as an independent mechanism of predisposition to the development of atrophic gastritis.

Background: CD79b is a B-cell-specific antigen that is crucial to the B-cell receptor and is considered a key target for treatment in aggressive B-cell lymphomas. Methods: While immunohistochemical studies have shown widespread expression of CD79b in mature B-cell-derived lymphomas, flow cytometry allows for precise measurement and differentiation between surface and intracellular localization. Results: In our comparative analysis, we discovered that CD79b expression percentages and mean fluorescence intensity (MFI) were lower in a group of 127 cases of aggressive B-cell lymphomas compared to a control group of benign reactive hyperplasia. We also observed significant variability in the surface expression of CD79b among lymphoma cases, with 18% showing predominantly intracellular positivity. There was a strong correlation between the surface expression of CD79b and clonal light chains. Notably, primary mediastinal B-cell lymphomas exhibited significantly lower surface CD79b expression compared to other lymphoma subtypes (median 0.8% IQR 0-48.5 vs. 80% IQR 24-97, p = 0.0005). Furthermore, patients over 60 years old and those with a higher Revised International Prognostic Index (R-IPI) had significantly higher CD79b expression, both of which are associated with a significant benefit from adding an anti-CD79b drug conjugate to first-line chemotherapy in diffuse large B-cell lymphomas. Conclusions: In conclusion, the quantitative flow cytometric analysis of CD79b surface expression in aggressive B-cell lymphomas provides clinically relevant information, highlighting its potential usefulness in guiding therapeutic decisions.

Follicular lymphoma is the second most diagnosed lymphoma in Western Europe. Significant advancements have considerably improved the survival of FL patients. However, 10-20% of these patients are refractory to standard treatments, and most of them will relapse. The treatment of follicular lymphoma patients with multiply relapsed or refractory disease represents an area of high-unmet needing new treatments with stronger efficacy. Chimeric antigen receptor (CAR)-T cell therapy targeting B-cell antigens, such as CD19 or CD20, is emerging as an efficacious treatment for R/R follicular lymphoma patients, particularly for those with early relapse and refractory to alkylating agents and to anti-CD20 monoclonal antibodies, resulting in a high rate of durable responses in a high proportion of patients.

Image-guided core needle biopsies (IG-CNB) represent a minimally invasive approach for obtaining tissue in patients with lymphadenopathy and suspected lymphoma. Despite their utility, diagnostic challenges persist, with lower efficacy compared with excisional biopsies. Our study aimed to evaluate the potential utility of incorporation of flow cytometry (FC) alongside immunohistochemistry (IHC) when performing IG-CNB for suspected lymphoproliferative diseases. Analyzing 170 consecutive cases, guided by ultrasound (n = 94) or computer tomography (n = 76), we employed a diagnostic algorithm, already established in our laboratory practice, utilizing three antibody cocktail-equipped tubes tailored for defining lymphomas, particularly those of B-cell origin. FC expedited the diagnostic process, yielding presumptive results in 87.6% of cases within 48 h, with a positive predictive value of 98%. Addition of FC to routine IHC enhanced the diagnostic rate from 91.2% to 95.3%, reducing IG-CNB failure rate by 45%, from 8.8% to 4.7%. This enhancement was particularly notable for deep-seated sites and in the setting of suspected disease recurrences. Consequently, FC emerges as a valuable adjunctive tool, allowing for the improvement of diagnostic performance, with a particular focus on the ability to quantify the expression of surface markers for targeted therapies, and holding the potential to diminish the necessity for repeat excisional biopsies subsequent to IG-CNB procedures.

EUS-FNB has been introduced in clinical practice as a less invasive diagnostic approach with respect to surgery. We performed a single-center retrospective study on the diagnostic efficacy of EUS-guided FNB, including 171 patients with lymph nodes, splenic, and extranodal lesions that underwent EUS for FNB at our institution. Excluding 12 patients who did not undergo FNB and 25 patients with a previous diagnosis of a solid tumor, we included 134 patients with clinical/radiological suspect of a lymphoproliferative disease, including 20 patients with a previous history of lymphoma. Out of the 134 biopsies, material of diagnostic quality was obtained in 111 procedures (84.3%). Histological examination of the EUS-FNB samples produced an actionable diagnosis in 100 cases (74.6%). Among the patients without an actionable diagnosis, a second, different diagnostic procedure produced a further eight diagnoses of lymphoma. Therefore, the sensitivity of EUS-FNB for diagnosing lymphomas was calculated to be 86.4% (51/59). Assignment of lymphomas to WHO classification subtypes was possible in 47/51 (92%) of the cases. In conclusion, EUS-FNB is an effective procedure for the histological characterization of lesions that are suspected to be lymphoproliferative disease, allowing for an actionable diagnosis in 75% of cases.

Book Citations: Authors, Title, HemaSphere, 2023;7(S3):pages. The individual abstract DOIs can be found at https://journals.lww.com/hemasphere/pages/default.aspx. Disclaimer: Articles published in the journal HemaSphere exclusively reflect the opinions of the authors. The authors are responsible for all content in their abstracts including accuracy of the facts, statements, citing resources, etc. 2673 Infused bags from responders at M3 and M6 showed a higher percentage of CAR+CD8+ cells than non-responders (56% vs 27% p=0.02 and 55.4% vs 27.3% p 0.034 respectively). As a consequence, we observed significant difference in the ratio CD4+/CD8+ CAR+ in infused bags between responders at M3 vs non-responders (ratio 0.74 vs 2.47, p=0.011) (Figure 1A) We used a ROC analysis to identify an ideal ratio CD4+/CD8+ CAR+ cut-off among infused CAR-T to discriminate responders at M3: we found that a ratio of 1.12 had 100% sensitivity and 70 % specificity in identifying responses at M3 (AUC 82%, p=0.001). (Figure 1B) In a logistic regression analysis, the CD4+/CD8+ CAR+ ratio was confirmed as a variable to predict response at M3 (Odds Ratio 23.3 p=0.012) and M6 (Odds Ratio 10 p=0.028). Summary/Conclusions We found that a higher percentage of CAR+CD8+ T cells and a lower ratio CD4+/CD8+ CAR+ in the infusion bags are significant predictors for response at 3 and 6 months in pts treated with CD19-CAR-T. We observed that a very low percentage of CAR+CD8+EM T cells may be associated with early treatment failure at 1 month. These data support the role of CD8-mediated cytotoxic mechanism of action by CAR-T cells, and may be useful for strategies of potential empowerment of manufactured products in order to raise CAR-T efficacy. HemaSphere | 2023;7(S3) EHA2023 Hybrid Congress Copyright Information: (Online) ISSN: 2572-9241 © 2023 the Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the European Hematology Association. This is an open access Abstract Book distributed under the Attribution-NonCommercial-NoDerivs (CC BY-NC-ND) which allows third parties to download the articles and share them with others as long as they credit the author and the Abstract Book, but they cannot change the content in any way or use them commercially. Abstract Book Citations: Authors, Title, HemaSphere, 2023;7(S3):pages. The individual abstract DOIs can be found at https://journals.lww.com/hemasphere/pages/default.aspx.Book Citations: Authors, Title, HemaSphere, 2023;7(S3):pages. The individual abstract DOIs can be found at https://journals.lww.com/hemasphere/pages/default.aspx. Disclaimer: Articles published in the journal HemaSphere exclusively reflect the opinions of the authors. The authors are responsible for all content in their abstracts including accuracy of the facts, statements, citing resources, etc. 2674

The peer review history for this article is available at https://publons.com/publon/10.1002/hon.3119. The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.

Supplementary Table 1 from A Transcriptional Profiling Study of CCAAT/Enhancer Binding Protein Targets Identifies Hepatocyte Nuclear Factor 3β as a Novel Tumor Suppressor in Lung Cancer

Asymptomatic patients with follicular lymphoma (FL) and a low tumour burden can be followed without initial therapy, a strategy called watchful waiting (WW). Prediction of the time to treatment (TTT) is still a challenge. We investigated the prognostic value of baseline total metabolic tumour volume (TMTV) and whole-body total lesion glycolysis (WB-TLG) to predict TTT in patients with FL on WW. We conducted a retrospective study of 54 patients with FL (grade 1–3a) diagnosed between June 2013 and December 2019, staged with FDG PET/CT, and managed on WW. Median age was 62 years (range 34–85), stage was advanced (III–IV) in 57

Purpose One of the main limiting factors of whole-brain radiation therapy (WBRT) for primary central nervous system lymphoma (PCNSL) is the impairment of neurocognitive functions (NCFs), which is mainly caused by radiation-induced injury to the hippocampus. With a view to preventing NCF impairment and personalizing treatment, we explored the feasibility of sparing the hippocampus during WBRT by correlating the sites of PCNSL lesions with the hippocampus. Methods and materials Pre-treatment MR images from patients who underwent WBRT between 2010 and January 2020—and post-radiotherapy images in cases of relapse—were imported into the Varian Eclipse treatment-planning system and registered with the simulation CT. We constructed three 3-dimensional envelopes around the hippocampus at distances of 5, 10 and 15 mm and also contoured primary lesions and recurrences. Results We analyzed 43 patients with 66 primary lesions: 9/66 (13.6%) involved the hippocampus and 11/66 (16.7%) were located within 5 mm of it. Thirty-six lesions (54.5%) were situated more than 15 mm from the hippocampus, while 10/66 (15.2%) were between 5 and 15 mm from it. The most common location was in deep brain structures (31%). Thirty-five of the 66 lesions relapsed: in field in 14/35 (40%) and outfield in 21/35 (60%) in different sites. Globally, 16/35 recurrences (45.7%) were located in the hippocampus or within 5 mm of it. Conclusion These data show that routinely sparing the hippocampus is not feasible. This approach could be considered in selected patients, when the lesion is more than 15 mm from the hippocampus.

Topic: 18. Indolent and mantle-cell non-Hodgkin lymphoma - Clinical Background: First-line immunochemotherapy of Follicular lymphoma (FL) combining anti-CD20 antibodies Rituximab or Obinutuzumab with Bendamustine (R/O-B) followed by maintenance therapy results in high rates of response and long progression-free survival. A major adverse effect of this regimen is long-lasting lymphopenia as a risk factor for infections. Aims: We performed a cross-sectional and longitudinal study on lymphocyte T cell subsets during anti-CD20 maintenance therapy using flow-cytometry. Associations between T cell subset counts and infectious events were analyzed. Methods: We enrolled 55 patients (pts) with high tumor burden FL between 2017 and 2021 who received first-line treatment with anti-CD20 plus Bendamustine (R/O-B) or CHOP regimen (R-CHOP), followed by maintenance. We collected peripheral blood samples at the following time points: end of induction (EoI), at +6, +12, +18 and +24 months after. We analyzed T cell subsets defined by the maturation status (Naïve, Central Memory, Effector Memory, and TEMRA) in addition to absolute CD4+ and CD8+ T cell counts. Results: We enrolled 55 pts: 49% females, 51% males, median age 60 years (range 50- 80), who received R/O-B (76%) and R-CHOP (24%). At the EoI median CD4+ counts were lower in the R/O-B group compared to R-CHOP (119/mmc vs 402/mmc; p =0.0001). Despite the trend of CD4+ counts to increase over time following R/O-B, they remained significantly lower at +6 (155/mmc vs 637/mmc p=0.0008) and +12 (264.6/mmc vs 497.3/mmc; p=0.027), when compared to R-CHOP. Most strikingly, the median CD4+ naive count was extremely low in R/O-B group at EoI (3.43/mmc vs 71.3/mmc; p=0.003) and up to +12 (26/mmc vs 173/mmc; p=0.04), while no differences were observed at +18 and +24. We didn’t find differences in T CD8+ counts and subsets between R/O-B and R-CHOP group at any time. Gender and age had a significant impact on T cell recovery in R/O-B treated pts. Males (M) had prolonged lower CD4+ counts respect to females (F) (146/mmc vs 316/mmc at +12 for M vs F, p=0.018; 230/mmc vs 425/mmc at +24 for M vs F, p=0.026). Moreover, the proportion of naïve CD4+ T cells remained lower in M than in F (from 9% vs 15% at +6, p=0.05, to 11% vs 35.4% at +24, p=0.045). As age increases lower naïve CD4+ count is observed at +6 (p=0.0019) and +12 months (p=0.016). Infectious episodes were registered during the 2 year-observation period in 47% of pts. 60% of infections were bacterial, 30% reactivation of VZV, and 10% fungal. The cumulative incidence rate of infection was significantly different between R/O-B and R-CHOP (59% vs 7 % p= 0.003). In univariate analysis age>60 years and more than 12 months to reach CD4+>200/mmc were identified as risk factors for infections in the R/O-B group (respectively OR 4.87, CI 1.23 -19, p =0.024; OR 7, CI 95% 1.59-30, p =0.014). These variables were confirmed in multivariate analysis (respectively OR 4.34, CI 95% 1.012-18.6, p=0.048; OR 1.13, CI 95% 1-1.28, p=0.05). Summary/Conclusion: FL pts undergoing first-line therapy with R/O-B experienced a prolonged and deep CD4+T and lymphopenia, in particular of the naïve CD4+ T cell subset compared with pts treated with R-CHOP. Elderly Male pts showed a particularly delayed recovery of CD4+ T cell counts. Prolonged CD4+ T cell lymphopenia over 12 months and age>60 ys are risk factors for infections, and could be indicators for the necessity to prolong anti-microbial prophylaxis. Moreover, benefits of the R/O-B regimen should be weighed against the risks of infections in particular among elderlies. Keywords: Follicular lymphoma

The head-and-neck area is one of the most common sites for nodal and extranodal localization of lymphomas. Clinical presentation of lymphomas in the head and neck region varies from slowly growing indolent lymphomas to highly aggressive lymphomas causing compression of the upper airways for which a timely diagnosis is warranted. The aim of this study was to evaluate the predictive value of flow cytometry (FC) in the diagnosis of head and neck lesions suspicious for lymphoma. We analyzed cell suspensions of 50 excisional biopsies using FC and compared the results with histological examination. Using a sequential three-tube antibody panel, we found a high level of diagnostic concordance between FC and histology in the 30 non-Hodgkin lymphomas (NHL). When no aberrant B or T cell population was identified in FC, indirect signs were helpful to predict diagnoses other than NHL, such as Hodgkin Lymphoma, metastatic lesions of epithelial tumors or reactive hyperplasia. In conclusion, FC can provide useful diagnostic information in a short turnaround time when clinical evaluation by hematologists and otolaryngologists raised the suspicion of lymphoma.

Background Malignancies represent 15–50% of total causes of pericardial effusions (PE). Routine analyses recommended to be performed on pericardial fluid include general chemistry, cytology, polymerase chain reaction, and microbiological cultures. Multicolor flow cytometry (FC) is a laboratory test that already proved to be useful in the detection of lymphoproliferative and metastatic malignancies in pleural and peritoneal effusions, but current guidelines do not mention its use on PE to reach a diagnosis. Methods Our institutional protocol foresees to routinely perform a multicolor FC analysis on pericardial fluid samples obtained by pericardiocentesis, in addition to other guidelines-recommended analyses. A sample of 15–30 ml is analyzed using a lyse and wash staining method using combination panels of antibodies, allowing to detect specific cellular subpopulations, analyzing tens to hundreds of thousands of cells in few seconds. The present manuscript aims to report our single-center experience with this diagnostic tool in patients presenting with PE requiring pericardiocentesis. Results Routine use of multicolor FC on pericardial fluid samples in our institution allowed to reach a definite diagnosis of cardiac lymphomas in two patients presenting with otherwise unexplained severe PE. This resulted in immediate start of combined immunotherapy, with patients’ clinical improvement. At 6 months follow-up both patients are alive and presented a complete disease regression. Conclusion Preliminary evidence from routine use of multicolor FC on PE support that this is a promising tool to reach a rapid diagnosis of hematological malignancies with heart involvement, leading to a prompt initiation of targeted therapies.

A 56-year-old female patient came into the emergency room for epistaxis and the appearance of hemorrhagic petechiae on the hips and abdomen. She had a clinical history of primary melanoma of the nasal mucosa, a rare subtype of melanoma (1% of all malignant melanomas),1 characterized, compared with all malignant melanomas, by later onset (median age 70 vs. 55), worse five years survival (25% vs. 80%) and advanced stage at diagnosis, being asymptomatic in almost all cases.2 She was treated with surgical resection, representing the primary treatment modality2, followed by radiotherapy and low-dose interferon. She then underwent a lobectomy for pulmonary metastatic localization two years later. At the time of presentation to our hospital, she underwent proton therapy, a form of external beam radiotherapy,3 for sphenoidal sinuses recurrence. Upon arrival, vital signs (blood pressure, heart and respiratory rate, and temperature) were normal. Blood tests showed anemia (hemoglobin 9.2 g/dL) and marked thrombocytopenia (platelet count 16 × 109/l); white blood cell count (5.64 × 109/l) and differential were normal, except for five circulating nucleated red blood cells per 100 WBC at peripheral blood smear. Additional laboratory tests showed increased serum lactate dehydrogenase (LDH: 1112 U/l), C-reactive protein (PCR: 7.2 mg/L), and D-Dimer (12451 ng/mL). Nutritional deficiencies (iron, vitamin B12, and folate), thrombotic thrombocytopenic purpura, autoimmune hemolytic anemia, infections, and hematologic malignancies were considered in the differential diagnosis. Bone marrow aspirate smears showed reduced cellularity with an almost complete absence of the megakaryocyte lineage. Large atypical immature blast cells infiltrated all areas of the bone marrow smear. They were either cohesive in small clusters (Figure 1A) or non-cohesive, scattered throughout the slide (Figure 1B) and, particularly, within the smeared bone marrow particles and in the feathered edge of the smear. Nuclei occupied a large part of the cytoplasm (moderately high nucleo-cytoplasmic ratio) and had a predominant blastic aspect. Nuclear chromatin was smooth and finely homogeneous, with some prominent and even giant prominent nucleoli, well visible thanks to thick circular borders. The cytoplasm was relatively abundant, with many vacuoles of different sizes, disorderly dispersed, and even in supranuclear position. Cytoplasm staining was basophilic and sometimes could appear empty due to the fusion of vacuoles in large unstained lakes (Figure 1A, black arrows). Nuclear and cytoplasmic borders were sharp and regular in most cases. Besides vacuoles, two types of cytoplasmic inclusions were present. They allowed a morphological differentiation from Burkitt-type lymphoma, rhabdomyosarcoma, or metastatic carcinoma. Firstly, there were dark pigment bodies of melanin (confirmed by positive immunohistochemistry for Melan-A) (Figure 1C, black arrow). Secondly, giant vacuoles included cells in various states of degradation, showing hemophagocytosis and auto-hemophagocytosis by these tumor cells (Figure 1B,C, empty arrows). Bone marrow core biopsy confirmed the involvement by metastatic melanoma and showed interstitial and macronodular infiltration by cells with pigmented cytoplasm cells (positive for Melan-A/Tyrosinase and negative for CD34, CD11, MPO, and S-100). Bone marrow metastatic melanoma infiltration is considered infrequent and has been described in a relatively small number of patients.4 The cell morphological features have been variably reported as large blasts of heterogeneous size, with immature heterogeneous nuclei and basophilic cytoplasm, which contains melanin pigment inclusions in typical cases. S-100 positivity was not observed in our case, while it is described as frequent in the literature. However, the positivity of Melan-A/tyrosinase and the clinical history confirmed the diagnosis. Data are available on request

PurposeOne of the main limiting factors of whole-brain radiation therapy (WBRT) for primary central nervous system lymphoma (PCNSL) is the impairment of neurocognitive functions (NCFs), which is mainly caused by radiation-induced injury to the hippocampus. With a view to preventing NCF impairment and personalizing treatment, we explored the feasibility of sparing the hippocampus during WBRT by correlating the sites of PCNSL lesions with the hippocampus. Methods and MaterialsPre-treatment MR images from patients who underwent WBRT between 2010 and January 2020 - and post-radiotherapy images in cases of relapse - were imported into the Varian Eclipse treatment-planning system and registered with the simulation CT. We constructed three 3-dimensional envelopes around the hippocampus at distances of 5, 10 and 15mm and also contoured primary lesions and recurrences.ResultsWe analyzed 43 patients with 66 primary lesions: 9/66 (13.6%) involved the hippocampus and 11/66 (16.7%) were located within 5mm of it. Thirtysix lesions (54.5%) were situated more than 15 mm from the hippocampus, while 10/66 (15.2%) were between 5 and 15 mm from it. The most common location was in deep brain structures (31%). Thirty-five of the 66 lesions relapsed: 14/35 (40%) in the same location and 21/35 (60%) in different sites. Globally, 16/35 recurrences (45.7%) were located in the hippocampus or within 5mm of it.ConclusionThese data show that routinely sparing the hippocampus is not feasible. This approach could be considered in selected patients, when the lesion is more than 15 mm from the hippocampus.