PMC7171624_01
Coronal views of computer tomography scan of the abdomen performed one month before (a) and three months after (b) starting therapy with golimumab demonstrating the massive enlargement of the spleen (arrow).
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An abdominal computed tomography (CT) scan demonstrated the presence of massive splenomegaly (Figure 1), with focal hypoattenuation and normal uptake on positron emission tomography (PET) scan.
Peripheral blood smear showing atypical lymphocytes with abundant cytoplasm, hugging of a red blood cell (arrow), tiny cytoplasmic vacuoles, and mature chromatin, resembling Downey type II cells seen in acute infectious mononucleosis. Staining: Wright-Giemsa; magnification: 100x.
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Peripheral blood smear revealed the presence of Downey type II cells (Figure 2), and an interferon-gamma release assay was negative.
Flow cytometry (a) and B-cell immunoglobulin gene rearrangement studies (b) demonstrating the clonal nature of the golimumab-induced lymphoproliferative disorder. An abnormal population of B cells (CD-45+, CD-19+) with a dim expression of surface kappa light chain and negative for lambda light chain. B electropherograms of fluorescently labeled PCR products detected by capillary gel electrophoresis showing polyclonality, Gaussian distribution of products, using the BIOMED-2 primer sets IGH FR 1, FR2, FR3, IGK VJ, and IGK VKde. Two broad dominant peaks (234.06 bp and 285.08 bp) were identified with the IGK VKde primer set, which targets the deleting element of the kappa light chain. This result is consistent with the presence of two B-cell clones.
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Repeat flow cytometry revealed that the B cells doubled to 20-25% (Figure 3(a)), biclonal for the IGK gene (Figure 3(b)) on B-cell receptor (BCR) gene rearrangement studies.