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According to expert guidelines, lymph node surgical excision is the standard of care for lymphoma diagnosis. However, core needle biopsy (CNB) has become widely accepted as part of the lymphoma diagnostic workup over the past decades. The aim of this study was to present the largest multicenter inventory of lymph nodes sampled either by CNB or surgical excision in patients with suspected lymphoma and to compare their diagnostic performance in routine pathologic practice. We reviewed 32 285 cases registered in the French Lymphopath network, which provides a systematic expert review of all lymphoma diagnoses in France, and evaluated the percentage of CNB and surgical excision cases accurately diagnosed according to the World Health Organization classification. Although CNB provided a definitive diagnosis in 92.3% and seemed to be a reliable method of investigation for most patients with suspected lymphoma, it remained less conclusive than surgical excision, which provided a definitive diagnosis in 98.1%. Discordance rates between referral and expert diagnoses were higher on CNB (23.1%) than on surgical excision (21.2%; P = .004), and referral pathologists provided more cases with unclassified lymphoma or equivocal lesion through CNB. In such cases, expert review improved the diagnostic workup by classifying ∼90% of cases, with higher efficacy on surgical excision (93.3%) than CNB (81.4%; P < 10-6). Moreover, diagnostic concordance for reactive lesions was higher on surgical excision than CNB (P = .009). Overall, although CNB accurately diagnoses lymphoma in most instances, it increases the risk of erroneous or nondefinitive conclusions. This large-scale survey also emphasizes the need for systematic expert review in cases of lymphoma suspicion, especially in those sampled by using CNB., (© 2022 by The American Society of Hematology.)

Biological hallmarks of splenic marginal zone lymphoma (SMZL) remain poorly described. Herein, we performed in‐depth SMZL characterization through multimodal single‐cell analyses of paired blood/spleen samples. The 3'‐single‐cell RNA‐sequencing, Cellular Indexing of Transcriptomes and Epitopes by sequencing, and 5'‐V(D)J single‐cell RNA‐sequencing datasets were integrated to characterize SMZL transcriptome profiles, including B‐cell receptor and T‐cell receptor repertoires. Hyperexpanded B‐cell clones in the spleen were at a memory‐like stage, whereas recirculating tumor B‐cells in blood encompassed multiple differentiation stages, indicating an unexpected desynchronization of the B‐cell maturation program in SMZL cells. Spatial transcriptomics showed the enrichment of T‐effector and T‐follicular helper (TFH) signatures in the nodular subtype of SMZL. This latter also exhibited gene‐based cell–cell interactions suggestive of dynamic crosstalk between TFH and cancer cells in transcriptomics, further substantiated by using imaging mass cytometry. Our findings provide a comprehensive high‐resolution description of SMZL biological hallmarks and characterize, for the first time in situ, inter‐ and intra‐patient heterogeneity at both transcriptomic and protein levels. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland. [ABSTRACT FROM AUTHOR]

Aims: Primary prostatic lymphomas (PPL) is exceedingly rare. The aim of this study was to investigate the largest series of PPL obtained from a nationwide expert pathologist network, and thus try to understand the pathophysiology of these tumours. Methods and results: Up to 66 000 lymphoma cases have been collected and submitted for central expert review by the French Lymphopath network. We confirm the low frequency of PPL (n = 77; 0.12%), all cases being of B‐cell origin. Diffuse large B‐cell lymphoma and small lymphocytic lymphoma were the most frequent subtypes, comprising 31% and 26% of cases respectively, followed by mucosa‐associated lymphoid tissue (MALT)/lymphoplasmacytic lymphoma (19%), follicular lymphoma (12%), mantle cell lymphoma (6%), Burkitt lymphoma (4%), and unclassified lymphoma (1%). Clinical data obtained in 25 cases suggests that PPLs are rather indolent tumours. Our hypothesis for B‐cell recruitment in the prostatic tissue was derived from the observation in chronic inflammation (prostatitis) of frequent heterotopic proliferation of high endothelial venules (HEVs). The latter are dedicated to lymphocyte entry into secondary lymphoid organs, here putatively driving circulating clonal B‐lymphocytes from the blood into the inflamed prostate. This may account for the relatively high incidence of small lymphocytic lymphoma consistently reported in series of primary or secondary prostatic lymphoma. As in other organs or glands, chronic inflammation may promote antigen‐dependent intraprostatic MALT lymphoma and diffuse large B‐cell lymphoma development. Conclusions: PPLs are exclusively of B‐cell origin, and chronic inflammation resulting from the proliferation of high endothelial venules could play some role in their development. [ABSTRACT FROM AUTHOR]