Serial regression of primary gastric diffuse large B cell lymphoma after Helicobacter pylori eradication therapy: A case report.

Key Clinical Message: Primary gastric diffuse large B-cell lymphoma (DLBCL), a rare malignancy linked to Helicobacter pylori (HP) infection, in this case regressed to low-grade lymphoma and then achieved complete remission after HP eradication (HPE), highlighting this unique interim change and the potential of HPE as an effective treatment for early-stage cases. Abstract: Primary gastric diffuse large B-cell lymphoma (DLBCL) is a rare malignancy. Like gastric mucosa-associated lymphoid tissue (MALT) lymphoma, HP infection is implicated in lymphomagenesis and has thus emerged as a therapeutic target. Studies have demonstrated the sustained efficacy of HP eradication alone for limited-stage primary gastric DLBCL. This report presents the case of a 53-year-old woman with stage IE gastric DLBCL who received triple therapy for HP eradication and experienced an interim histological transformation to MALT lymphoma, ultimately achieving complete pathologic remission. HP eradication therapy may represent a viable treatment option for patients with early-stage primary gastric DLBCL.

Nodal T-Follicular Helper Cell Lymphoma, Angioimmunoblastic-Type, Diagnosed in a Patient with Psoriasis Following COVID-19 Vaccination under Adalimumab Treatment: A Causal Association?

Biologics have expanded the armamentarium for psoriasis, but there has been a growing concern about the risk of lymphoma in patients under tumour necrosis factor (TNF)-α inhibitor and methotrexate. Besides, the mRNA-based coronavirus disease 2019 (COVID-19) vaccination was known to stimulate the proliferation of T-follicular helper cells. We report a case of a patient with psoriasis under adalimumab developing nodal T-follicular helper cell lymphoma, angioimmunoblastic-type following the mRNA-1273 COVID-19 vaccine. We suspect that adalimumab, methotrexate, Epstein-Barr virus (EBV) reactivation, previous reactive lymphoid hyperplasia and psoriasis per se predispose our patient to a lymphoma-prone condition, and the two doses of the mRNA vaccine act as the last straw.

Granulomatous lymphadenitis in Taiwan: Unraveling infantile peak and Bacillus Calmette-Guérin lymphadenitis.

BACKGROUND: Granulomatous lymphadenitis, a histopathological diagnosis, often indicates infections, such as those caused by mycobacterial and fungal agents. METHODS: We conducted an analysis of 1098 granulomatous lymphadenitis cases, examining age distribution, lymph node locations, and laterality. Molecular detection of Bacillus Calmette-Guérin (BCG) was performed on archived formalin-fixed paraffin-embedded tissue specimens. RESULTS: Our analysis revealed a bimodal age distribution, notably with a minor peak in infants. These infantile cases predominantly featured axillary involvement, frequently occurring on the left side. Positive rates of BCG identification decreased with age: <1 year, 71%; 1-2 year, 33%; 2-3 year, 13%; 3-4 year, 0%. Remarkably, only one of the 14 cases with molecularly confirmed BCG lymphadenitis had comments regarding BCG in the pathological report. Compared with patients born after 2016 (BCG at 5-8 months), those born before 2016 (BCG at birth) developed BCG lymphadenitis at a wider age range with right skewness (before 2016, 13 ± 11 months [range, 3-33 months] vs. after 2016, 10 ± 2 months [range, 8-13 months]). Four of the 14 BCG-positive cases had congenital heart disease. Seven patients received anti-tuberculosis drugs following surgical excision. No surgical complications were reported. CONCLUSIONS: BCG lymphadenitis constitutes a distinctive minor peak within the spectrum of granulomatous lymphadenitis in Taiwan. Pathologists should consider the possibility of BCG infection, especially in cases of infantile axillary, supraclavicular, neck lymphadenopathies on the left side. Moreover, BCG administration at 5-8 months may reduce delayed-onset BCG lymphadenitis.

Geographic EBV variants confound disease-specific variant interpretation and predict variable immune therapy responses.

ABSTRACT: Epstein-Barr virus (EBV) is a potent carcinogen linked to hematologic and solid malignancies and causes significant global morbidity and mortality. Therapy using allogeneic EBV-specific lymphocytes shows promise in certain populations, but the impact of EBV genome variation on these strategies remains unexplored. To address this, we sequenced 217 EBV genomes, including hematologic malignancies from Guatemala, Peru, Malawi, and Taiwan, and analyzed them alongside 1307 publicly available EBV genomes from cancer, nonmalignant diseases, and healthy individuals across Africa, Asia, Europe, North America, and South America. These included, to our knowledge, the first natural killer (NK)/T-cell lymphoma (NKTCL) EBV genomes reported outside of East Asia. Our findings indicate that previously proposed EBV genome variants specific to certain cancer types are more closely tied to geographic origin than to cancer histology. This included variants previously reported to be specific to NKTCL but were prevalent in EBV genomes from other cancer types and healthy individuals in East Asia. After controlling for geographic region, we did identify multiple NKTCL-specific variants associated with a 7.8-fold to 21.9-fold increased risk. We also observed frequent variations in EBV genomes that affected peptide sequences previously reported to bind common major histocompatibility complex alleles. Finally, we found several nonsynonymous variants spanning the coding sequences of current vaccine targets BALF4, BKRF2, BLLF1, BXLF2, BZLF1, and BZLF2. These results highlight the need to consider geographic variation in EBV genomes when devising strategies for exploiting adaptive immune responses against EBV-related cancers, ensuring greater global effectiveness and equity in prevention and treatment.

Comparison of the 2022 world health organization classification and international consensus classification in myelodysplastic syndromes/neoplasms.

In 2022, two novel classification systems for myelodysplastic syndromes/neoplasms (MDS) have been proposed: the International Consensus Classification (ICC) and the 2022 World Health Organization (WHO-2022) classification. These two contemporary systems exhibit numerous shared features but also diverge significantly in terminology and the definition of new entities. Thus, we retrospectively validated the ICC and WHO-2022 classification and found that both systems promoted efficient segregation of this heterogeneous disease. After examining the distinction between the two systems, we showed that a peripheral blood blast percentage ≥ 5% indicates adverse survival. Identifying MDS/acute myeloid leukemia with MDS-related gene mutations or cytogenetic abnormalities helps differentiate survival outcomes. In MDS, not otherwise specified patients, those diagnosed with hypoplastic MDS and single lineage dysplasia displayed a trend of superior survival compared to other low-risk MDS patients. Furthermore, the impact of bone marrow fibrosis on survival was less pronounced within the ICC framework. Allogeneic transplantation appears to improve outcomes for patients diagnosed with MDS with excess blasts in the ICC. Therefore, we proposed an integrated system that may lead to the accurate diagnosis and advancement of future research for MDS. Prospective studies are warranted to validate this refined classification.

Kikuchi disease in acute leukaemia: a distinct clinical syndrome with HLA association.

AIMS: To report the clinicopathological features of Kikuchi disease in patients with acute leukaemia, emphasising similarities among cases. METHODS AND RESULTS: In a cohort of 454 Kikuchi disease patients, we identified three cases of concurrent acute leukaemia. These patients shared similar clinical traits, with Kikuchi disease emerging approximately a month after induction chemotherapy onset, featuring neck-region lymphadenopathy. Notably, two patients were middle-aged, deviating from the typical age distribution of Kikuchi disease. Histologically, these cases aligned with typical Kikuchi disease. Negative immunohistochemical stains (CD34, CD117, ERG, TdT) indicated the absence of extramedullary leukaemic infiltration. Herpes simplex virus immunohistochemical staining was also negative. Significantly, a human leucocyte antigen (HLA) association was observed in these three cases. HLA-B*15:01, C*04:01, and DRB1*04:06 were more prevalent in these patients compared to the general population (compared with three independent control cohorts: Taiwanese Han Chinese (n = 504), Tzu Chi Taiwanese bone marrow donors (n = 364) and Hong Kong Chinese (n = 5266)). CONCLUSIONS: Our study underscores the unique link between Kikuchi disease and acute leukaemia, characterised by specific features and HLA associations. This underlines Kikuchi disease as a possible differential diagnosis in pertinent clinical scenarios. Furthermore, this syndrome offers insights into postchemotherapy immunology in acute leukaemia, enhancing comprehension.

Necrosis in lymph nodes and their differential diagnoses: application of reticulin staining.

This study aimed to enhance the histopathological diagnosis of necrotic lymph node specimens. A chart review was conducted, revealing that the most common causes of lymph node necrosis were Kikuchi disease (33%), granulomatous inflammation (25%), metastasis (17%), and lymphomas (12%). Histological analysis of necrotic tissue in 333 specimens demonstrated significant differences between the four diseases. The necrotic tissue of Kikuchi disease was amorphous, and hypercellular, and exhibited karyorrhexis and congestion. Granulomatous inflammation presented amorphous necrotic tissue with a nodular-like pattern. Metastasis exhibited heterogeneous morphology that varied between cancer types. Lymphomas displayed extensive necrosis with ghost cells, congestion, and bubbles. Reticulin staining patterns also differed between diseases. Kikuchi disease and lymphomas exhibited preserved reticular fiber networks in the necrotic tissue, resembling the viable tissue. Granulomatous inflammation and metastasis showed disrupted reticular fiber networks in the necrotic tissue. Based on these findings, histological features and reticulin staining patterns can aid in diagnosing Kikuchi disease, granulomatous inflammation, metastasis, and lymphomas in necrotic lymph node specimens.

Nodal reactive proliferation of monocytoid B-cells may represent atypical memory B-cells.

BACKGROUND: Reactive lymphadenopathies such as toxoplasmosis and cytomegalovirus lymphadenitis are associated with monocytoid cell proliferation. Monocytoid cells are B-lymphocytes with an undetermined subset. METHODS: Using digital spatial profiling whole transcriptome analyses, this study compared monocytoid and control B-cells. The B-cell subset of monocytoid cells was assigned according to gene expression profiles. RESULTS: This study identified 466 differentially expressed genes between monocytoid and control B-cells. The cellular deconvolution algorithm identified monocytoid cells as memory B-cells instead of as naïve B-cells. A comparison of the upregulated genes revealed that atypical memory B-cells had the largest number of genes overlapping with monocytoid cells compared with other memory B-cell subsets. Atypical memory B-cell markers, namely TBX21 (T-bet), FCRL4 (IRTA1), and ITGAX (CD11c), were all upregulated in monocytoid cells. Similar to atypical memory B-cells, monocytoid cells exhibited (1) upregulated transcription factors (TBX21, TOX), (2) upregulated genes associated with B-cell inhibition (FCRL5, FCRL4) and downregulated genes associated with B-cell activation (PIK3CG, NFKB1A, CD40), (3) downregulated cell cycle-related genes (CDK6, MYC), and (4) downregulated cytokine receptors (IL4R). This study also analyzed the expression of monocytoid cell signature genes in various memory B-cell subsets. Atypical memory B-cells exhibited a gene expression pattern similar to that of monocytoid cells, but other memory B-cell subsets did not. Furthermore, monocytoid cells and marginal zone lymphomas differed in gene expression profiles. CONCLUSION: Spatial transcriptomic analyses indicated that monocytoid cells may be atypical memory B-cells.

Lymph Nodes With Increased IgG4-positive Plasma Cells and Patterns Suspicious for IgG4-related Disease: Can Lymph Nodes Be the Only Site of Disease?

Lymphadenopathy with increased immunoglobulin (Ig) G4 + plasma cells can be a nonspecific finding or a manifestation of immunoglobulin G4-related disease (IgG4-RD). It remains unclear whether there are characteristic pathologic features of IgG4-RD involving lymph nodes, or if IgG4-RD lymphadenopathy can occur without other manifestations of IgG4-RD. In this study, we assessed 55 lymph node biopsy specimens (44 men and 11 women with a mean age of 55 y) with increased IgG4 + plasma cells that had 1 of the 6 well-described pathologic patterns. We also correlated these findings with IgG4 serum levels and followed these patients for 7 to 108 months (mean, 34.9 mo) for the occurrence of extranodal IgG4-RD. We further compared lymphadenopathy in patients who developed other manifestations of IgG4-RD (RD + , n=20, 36%) versus those who did not (RD - , n=35, 64%). We found that there were only minor significant differences between 2 groups, including frequency of receiving treatment (RD + , 90% vs. RD - , 60%, P =0.021) and higher serum levels of C-reactive protein (>8 mg/L, RD + , 53% vs. RD - , 13%, P =0.007). Other differences were either borderline or not significant, including mean age (RD + , 59.8 y vs. RD - , 51.9 y, P =0.097), male-to-female ratio (RD + , 16:4 vs. RD - , 28:7, P =1), constitutional symptoms (RD + , 25% vs. RD - , 9%, P =0.096), multiple enlarged lymph nodes (RD + , 45% vs. RD - , 26%, P =0.143), good response to therapy (RD + , 94% vs. RD - , 94%, P =1); higher serum IgG4 levels (>280 mg/dL, RD + , 75% vs. RD - , 51%, P =0.086), anemia (RD + , 45% vs. RD - , 43%, P =0.877), leukopenia (RD + , 0% vs. RD - , 3%, P =0.446), thrombocytopenia (RD + , 10% vs. RD - , 6%, P =0.556), positivity for antinuclear antibody (RD + , 24% vs. RD - , 29%, P =0.688), elevated serum levels of lactate dehydrogenase (>225 U/L, RD + , 0% vs. RD - , 20%, P =0.064), elevated serum IgE level (>100 IU/mL, RD + , 75% vs. RD - , 92%, P =0.238), and hypergammaglobulinemia (RD + , 90% vs. RD - , 86%, P =0.754). There were also no differences in morphologic patterns ( P =0.466), IgG4 + cell location ( P =0.104), eosinophil counts (RD + , 10.3±11.3 vs. RD - , 13.4±17.5, P =0.496), Epstein-Barr virus positivity (RD + , 35% vs. RD - , 60%, P =0.074), and Epstein-Barr virus-positive cell location ( P =0.351). Our findings suggest that there are minimal differences between stringently defined IgG4-RD lymphadenopathy with versus without other manifestations of IgG4-RD. These findings also suggest the existence of IgG4-RD lymphadenopathy as the sole presentation of IgG4-RD.

Cerebrospinal fluid soluble programmed death-ligand 1 is a useful prognostic biomarker in primary central nervous system lymphoma.

The increased expression of programmed death-ligands 1 and 2 (PD-L1 and PD-L2, respectively) on tumour cells contributes to immune evasion, suggesting that these proteins are attractive therapeutic targets. This study aimed to evaluate the validity of cerebrospinal fluid (CSF) soluble PD-L1 (sPD-L1) and soluble PD-L2 (sPD-L2) as biomarkers for primary central nervous system lymphoma (PCNSL). We determined the CSF concentrations of sPD-L1 and sPD-L2 in 46 patients with PCNSL using enzyme-linked immunosorbent assays (ELISAs). A control group comprised 153 patients with other brain tumours, inflammatory/infectious status, or neurodegenerative diseases. Only CSF sPD-L1 levels were significantly higher in patients with PCNSL relative to the controls. CSF sPD-L1 also exhibited superior overall discrimination performance compared to CSF sPD-L2 in diagnosing PCNSL. Compared with patients with PCNSL with low CSF sPD-L1 levels, more patients with high levels had high serum lactate dehydrogenase levels, leptomeningeal involvement, and deep-brain involvement. Furthermore, CSF sPD-L1 could predict poor survival in PCNSL but CSF sPD-L2 could not. Intriguingly, CSF sPD-L1 levels were correlated with disease status and their dynamic changes post treatment could predict time to relapse. In conclusion, this study identified CSF sPD-L1 as a promising prognostic biomarker, indicating a therapeutic potential of PD-L1 blockade in PCNSL.

Incorporation of ultrasound-guided core biopsy with flow cytometry to assist the diagnosis of cervical lymphoma.

PURPOSE: The main purpose of surgery for cervical lymphoma is only for tissue sampling. To establish a patient-friendly diagnostic approach, we investigated the feasibility of ultrasound-guided core biopsy with flow cytometry in the patients with suspected cervical lymphoma. METHODS: We prospectively recruited patients with suspected cervical lymphoma from Nov 2017 till Jan 2021 in a referral medical center and performed retrospective interpretation of the prospectively acquired data. Ultrasound-guided core biopsy as the tissue sampling approach for the targeted lesions was performed in all patients. The ultrasound-guided core biopsy samples were analyzed by immunohistochemical stains and flow cytometry. The sample quality and the rate of definite and decisive diagnosis obtained by ultrasound-guided core biopsy alone and ultrasound-guided core biopsy with flow cytometry were evaluated. RESULTS: Total 81 consecutive patients were recruited for analysis. All ultrasound-guided core biopsy samples were qualified for analysis of pathology and flow cytometry. Pathologically, the diagnoses were definite and compatible with their flow cytometry results in 70 patients (86.42%). Either newly-diagnosed or recurrent cervical lymphoma/lymphoproliferative disorders with histologic transformation could be diagnosed by ultrasound-guided core biopsy with flow cytometry. Nine of the 11 patients with pathologically indefinite diagnosis became clinically decisive when flow cytometry was incorporated into the process, which improved the rate of decisive diagnosis to 98.77% (Odds ratio [95% CI]: 6.21 [1.28, 58.96]). CONCLUSION: Ultrasound-guided core biopsy combined with flow cytometry is suggested to serve as the first-line and patient-friendly diagnostic approach for the patients with suspected cervical lymphoma.

Isolated Primary Neurolymphomatosis in the Right Brachial Plexus Proven by Partial Nerve Biopsy.

INTRODUCTION: Isolated primary neurolymphomatosis is a rare manifestation of lymphoma, which is challenging to diagnose as there is only involvement of the nervous system, and nerve biopsy is not frequently pursued due to the high risk of irreversible complications. CASE REPORT: We present a case of isolated primary neurolymphomatosis of diffuse large B-cell lymphoma restricted to only the right brachial plexus and right axillary nerve. The clinical course has been indolent for several years. The initial examination, including MRI and the cerebrospinal fluid study, did not yield any evidence of malignancy. Eventually, due to the patient's symptom progression and the follow-up imaging findings, we conducted a partial nerve biopsy of the brachial plexus to confirm the malignancy. His neurological symptoms did not further deteriorate post-biopsy. CONCLUSION: Isolated primary neurolymphomatosis with an indolent course is rare and challenging to diagnose. Serial MRI and fluorodeoxyglucose-positron emission tomography reveal clues for tumor involvement. Partial nerve biopsy or targeted fascicular nerve biopsy could be an alternative for achieving a pathologic diagnosis.

Bone Marrow Histology in Hemophagocytic Lymphohistiocytosis.

CONTEXT.­: Bone marrow (BM) samples are obtained through aspiration and trephine biopsy. Hemophagocytic lymphohistiocytosis (HLH) has been largely studied in BM aspirate smears. OBJECTIVE.­: To investigate the histologic features of HLH in trephine biopsy. DESIGN.­: Patients with hemophagocytosis in BM aspirate smears were assigned to HLH (n = 127) and non-HLH (n = 203) groups. We quantified hematoxylin-eosin and CD68 immunohistochemical staining of their trephine biopsies. RESULTS.­: No significant correlation was noted in the hemophagocytosis count between aspirate smears and trephine biopsies. Compared with the non-HLH group, the HLH group had a higher hemophagocytosis count (13 versus 9 per tissue section, P = .046), lower percentage of the adipocytic area (36.7% versus 50.3%, P < .001), and higher percentage of the foamy area (19.1% versus 14.5%, P < .001). The HLH group had more histiocyte infiltrates (total histiocyte density, 9.2% versus 7.3%; P < .001) and more fat-infiltrating histiocytes (histiocyte density of the fat-associated part [HD-FA], 7.6% versus 6.2%; P < .001). We identified the following poor prognostic factors in the HLH group: age 50 years or older (median overall survival [mOS], 95 versus 499 days; P = .04), Epstein-Barr virus-positive T-cell lymphoproliferative diseases (EBV+TLPDs) (mOS, 51 versus 425 days; P < .001), hemophagocytosis count of 6 or higher per tissue section (mOS, 66 versus 435 days; P = .02), and HD-FA of 9% or greater (mOS, 61 versus 359 days; P = .02). Multivariate analysis revealed that age 50 years or older (hazard ratio [HR], 2.38; P < .001), EBV+TLPDs (HR, 2.07; P < .001), and hemophagocytosis count of 6 or higher per tissue section (HR, 2.07; P = .002) were independent prognostic factors for HLH. CONCLUSIONS.­: The HLH group had higher hemophagocytic activity, higher cellularity, a more foamy appearance, more histiocyte infiltrates, and more fat-infiltrating histiocytes. High hemophagocytic activity and marked histiocyte infiltrates in the BM fat were associated with poorer prognosis.

Identification and Targeting of the Developmental Blockade in Extranodal Natural Killer/T-cell Lymphoma.

Extranodal natural killer/T-cell lymphoma (ENKTL) is an aggressive, rare lymphoma of natural killer (NK) cell origin with poor clinical outcomes. Here we used phenotypic and molecular profiling, including epigenetic analyses, to investigate how ENKTL ontogeny relates to normal NK-cell development. We demonstrate that neoplastic NK cells are stably, but reversibly, arrested at earlier stages of NK-cell maturation. Genes downregulated in the most epigenetic immature tumors were associated with polycomb silencing along with genomic gain and overexpression of EZH2. ENKTL cells exhibited genome-wide DNA hypermethylation. Tumor-specific DNA methylation gains were associated with polycomb-marked regions, involving extensive gene silencing and loss of transcription factor binding. To investigate therapeutic targeting, we treated novel patient-derived xenograft (PDX) models of ENKTL with the DNA hypomethylating agent, 5-azacytidine. Treatment led to reexpression of NK-cell developmental genes, phenotypic NK-cell differentiation, and prolongation of survival. These studies lay the foundation for epigenetic-directed therapy in ENKTL. SIGNIFICANCE: Through epigenetic and transcriptomic analyses of ENKTL, a rare, aggressive malignancy, along with normal NK-cell developmental intermediates, we identified that extreme DNA hypermethylation targets genes required for NK-cell development. Disrupting this epigenetic blockade in novel PDX models led to ENKTL differentiation and improved survival. This article is highlighted in the In This Issue feature, p. 85.

Investigating early progression of Hodgkin lymphoma in a two-center analysis.

BACKGROUND/PURPOSE: The early progression of disease (POD) of Hodgkin lymphoma (HL) leads to a poor prognosis. To identify risk factors for early POD, this retrospective two-center cohort analysis was conducted. METHODS: Medical records of HL patients between 1998 and 2020 from two referral centers were reviewed. RESULTS: Two-hundred and sixty-nine patients were analyzed. The distribution of early vs. advanced stages was 51.1 vs. 48.9%, respectively. The 5-year progression free survival (PFS) was 63%, and the overall survival (OS) was 87% with a median follow-up of 52.0 months. The complete remission (CR) rate was 85.7%. Disease progression or relapsed disease occurred in 33.9% (n = 85) of patients while 17.0% of this cohort had early POD within 12 months of induction therapy. Patients with early POD had a worse median OS than those without (p < 0.001). Failure to achieve post-induction CR and high international prognostic score (IPS, 3-7) were independent risk factors for early POD. Compared with chemotherapy alone, consolidative radiotherapy after induction chemotherapy was associated with a lower risk of early POD (21.3% vs. 6.2%, p = 0.006). CONCLUSION: High IPS was an independent risk factor for early POD, which was less observed in those with consolidative radiotherapy.

A Clinicopathological Study of Cytomegalovirus Lymphadenitis and Tonsillitis and Their Association with Epstein-Barr Virus.

INTRODUCTION: Histopathological characteristics of cytomegalovirus (CMV) lymphadenitis have been well described. Rare studies have reported the immune status and clinical features. Clinically, experts believed that CMV lymphadenitis develops in immunocompromised and immunocompetent patients. Infectious mononucleosis (IM)-like syndrome is the most well-known clinical presentation. METHODS: We reviewed archived CMV immunohistochemical stains on lymphoid tissues. The clinicopathological features of CMV-positive cases were studied. RESULTS: For lymph nodes, we detected CMV in 29% (5/17) allogeneic peripheral blood hematopoietic stem cell transplantation (PBSCT) recipients, 29% (4/14) post-autologous PBSCT patients, 13% (6/47) patients treated with intravenous chemotherapy, and 9% (9/96) immunocompetent patients. We detected CMV in 7% (2/24) of tonsils but not in the nasopharynx, tongue base, or spleen specimens. The patients with iatrogenic immunodeficiency ranged from 37 to 76 years old. CMV infections developed a few years after lymphoma treatment (median duration after allogeneic PBSCT, 932 days; after autologous PBSCT, 370 days; and after chemotherapy, 626 days). The most common clinical presentation was neck mass (13/25, 42%), followed by asymptomatic image finding (10/25, 40%). Positron emission tomography/computed tomography (PET/CT) scan showed increased uptake compared to the liver in all patients (11/11, 100%). Of 10 lymphoma patients, 8 (80%) had a Deauville score of 4-5; they accounted for 30% (8/27) of lymphoma patients with false-positive PET/CT scan results. All cases were self-limiting. 96% (23/25) cases had Epstein-Barr virus coinfection, and EBER-positive cells were predominantly in a few germinal centers. CONCLUSIONS: Cytomegalovirus (CMV) lymphadenitis and tonsillitis were subclinical infections, not primary CMV infection with IM-like syndrome. The lymphadenopathy typically developed a few years after lymphoma treatments in the middle-aged and the elderly. The lesions mimicked lymphoma relapse in PET scans. Therefore, recognizing CMV infection in lymphoid tissues is of clinical importance.

Morphologic Spectrum of Lymphadenopathy in Adult-onset Immunodeficiency (Anti-interferon-γ Autoantibodies).

Adult-onset immunodeficiency syndrome (AOIS) caused by anti-interferon-γ autoantibodies is an emerging disease. Affected patients present typically with systemic lymphadenopathy, fatigue, and fever. We studied 36 biopsy specimens, 31 lymph nodes, and 5 extranodal sites, of AOIS confirmed by serum autoantibody or QuantiFERON-TB Gold In-Tube assay. We describe the morphologic features and the results of ancillary studies, including special stains, immunohistochemistry, and molecular testing. The overall median age of these patients was 60.5 years (range, 41 to 83 y) with a male-to-female ratio of 20:16. All biopsy specimens showed nontuberculous mycobacterial infection, and most cases showed the following histologic features: capsular thickening with intranodal sclerosing fibrosis, irregularly distributed ill-formed granulomas or histiocytic aggregates with neutrophilic infiltration, interfollicular expansion by a polymorphic infiltrate with some Hodgkin-like cells that commonly effaces most of the nodal architecture and proliferation of high endothelial venules. In situ hybridization analysis for Epstein-Barr virus-encoded RNA showed scattered (<1%) to relatively more common (4% to 5%) positive cells in 29 of 30 (97%) tested specimens, reflecting immune dysregulation due to an interferon-γ defect. In the 31 lymph node specimens, 23 (74%) cases showed increased immunoglobulin G4-positive plasma cells (4 to 145/HPF; mean, 49.7/HPF) with focal areas of sclerosis reminiscent of immunoglobulin G4-related lymphadenopathy, 4 (13%) cases resembled, in part, nodular sclerosis Hodgkin lymphoma, and 9 (29%) cases mimicked T-cell lymphoma. Among 33 patients with available clinical follow-up, 20 (61%) showed persistent or refractory disease despite antimycobacterial therapy, and 1 patient died of the disease. We conclude that the presence of ill-defined granulomas, clusters of neutrophils adjacent to the histiocytic aggregates, and some Epstein-Barr virus-positive cells are features highly suggestive of AOIS. A high index of clinical suspicion and awareness of the morphologic features and differential diagnosis of AOIS are helpful for establishing the diagnosis.