Unveiling the enigma: circulating flowerlike large B-lymphoma cells in the context of angioimmunoblastic T-cell lymphoma Free

A 71-year-old man with a history of angioimmunoblastic T-cell lymphoma (AITL, nodal T follicular helper-cell lymphoma, angioimmunoblastic type, World Health Organization classification) presented with absolute lymphocytosis (17.7 × 10³/μL). Peripheral blood (PB) film revealed large B lymphocytes with flower petal–like multilobulation (panels A-C, Wright-Giemsa stain, 100× objective), confirmed by flow cytometry (CD5⁻, CD10⁻, CD20⁺; accounting for 60% of total white blood cell count) and clonal immunoglobulin heavy chain (IgH) gene rearrangement by polymerase chain reaction. An excisional biopsy of the right axillary lymph node (LN) demonstrated diffuse large B-cell lymphoma (panel D, hematoxylin and eosin stain, 40× objective; and panel G), classified as nongerminal-center type (CD10⁻, BCL6⁻; MUM1 [panel E, immunostain, 40× objective]), alongside residual (<5%) AITL, supported by an aberrant T-cell population (CD3⁻, CD4⁺, CD2⁺, CD5⁺, CD7⁺) detected by flow cytometry (panel F, dot plot, CD3 vs CD4). Next-generation sequencing (panel I), performed on PB and LN samples, detected identical pathogenic variants in the BLM gene and TNFRSF14 gene but did not identify RhoA and TET2 mutations detected in original AITL diagnosis. Chromosomal microarray analysis (panel H) showed identical abnormalities both in PB (70% cells) and LN (80% cells), including gains of chromosome segments 3q and 10p and copy-neutral loss of heterozygosity of 1p, confirming the presence of circulating neoplastic B cells. The patient died 5 months after the diagnosis.

Circulating flower/clover-leaf lymphocytes are not exclusive to adult T-cell leukemia/lymphoma and may be observed in B-cell lymphomas. Although AITL often shows unusual lymphocyte variants, circulating clover-leaf B cells in this case mimic neoplastic T cells, potentially camouflaging an associated large B-cell lymphoma.

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