PMC9207196_01
Diffuse large B-cell lymphoma and classical Hodgkin's lymphoma diagnosis on lymph node biopsy. Large lymphoid cells with basophil cytoplasm, ovalar nuclei, and one or more nucleoli; small lymphocytes with a round nucleus were visible among the more numerous large cells (A, hematoxylin and eosin). The large cells were positive for CD20 (B) and BCL2 (C). CD5 was strongly positive in the small cells, while the large cells were partially and weakly positive (D). Large pleomorphic cells, with one or two ovalar nuclei and macro-nucleoli in a background of small lymphocytes and granulocytes with fibrosis (E, hematoxylin and eosin). The large cells were positive for CD30 (F) and PAX5 (H). Immunohistochemical staining for EBV-encoded RNA (EBER) was positive (G). (A, C, D-H: original magnification x40; B: original magnifications x20).
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The pathologist concluded for a DLBCL ( Figure 1 ). As already reported in more than half of HLs arising from CLL, immunohistochemical staining for EBV-encoding RNA (EBER) was positive and the pathologist concluded for EBV-positive, nodular sclerosis classical HL (cHL) (stage IIA) ( Figure 1 ).
Clonal relationships by Ig-rep and ASO-ddPCR and clinical evolution of the three lymphoid neoplasms. Clone "D" (indicated with a black star) was detected in the PB sample collected at the time of MBL diagnosis and was persistent in the PB collected at the time of DLBCL. Clone "R" (i.e., the clone identified in the lymph node biopsy at the time of DLBCL transformation, indicated with a red star) was undetectable by NGS of Ig-rep in the PB sample collected at the time of MBL diagnosis, whereas it became detectable by ASO-ddPCR in an interim PB sample collected during the "watch & wait" period (where it coexisted with clone "D"). Neither clone "D" nor clone "R" were detectable in the lymph node specimen collected at the time of HL. ASO-ddPCR, allele-specific oligonucleotide-droplet digital PCR; NGS, next-generation sequencing; Ig-rep, immunoglobulin repertoire; PB, peripheral blood; LN, lymph node; DLBCL, diffuse large B-cell lymphoma; HL, Hodgkin's lymphoma; MBL, monoclonal B-cell lymphocytosis; EBV, Epstein-Barr virus; R-COMP, rituximab, cyclophosphamide, liposomal doxorubicin, vincristine, prednisone; HD-MTX, high-dose methotrexate; CR, complete response; PD, progressive disease; RT, radiotherapy.
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ASO-ddPCR (data not shown); ii) detectable by ASO-ddPCR:but not by standard SS (data not shown):in an interim PB sample collected during the "watch & wait" period (i.e., 1 year after the first finding of MBL, in 2011), where it coexisted with the more represented clone "D" ( Figure 2 ); and iii) detectable, as well as clone "D," in the PB collected at the onset of DLBCL (2013), as shown by both Ig-rep ( Figure 2 ) and ASO-ddPCR (data not shown). A similar ASO-ddPCR-based approach was also applied on the HL sample, showing that neither clone "D" nor clone "R" was detectable in the collected lymph node specimen, thus suggesting a clonal unrelatedness with the two previous MBL and DLBCL.