PMC8656165_01
Maximum-intensity-projection images of 18F-FDG PET/CT at baseline (8 Sept) and 22 days later (30 Sept), 8 days after BNT162b2 mRNA vaccine injection in right deltoid. 8 Sept: hypermetabolic lymph nodes mainly in the supra-clavicular, cervical, and left axillary regions; restricted gastro-intestinal hypermetabolic lesions. 30 Sept: Dramatic increase in nodal and gastro-intestinal hypermetabolic lesions. Asymmetrical metabolic progression in the cervical, supra-clavicular and axillary area, more pronounced on the right side.
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F1
A 18F-FDG PET/CT revealed multiple voluminous hypermetabolic lymphadenopathies above and below the diaphragm as well as several extra-nodal hypermetabolic lesions (Figure 1, left panel). Furthermore, new hypermetabolic lymphadenopathies and new hypermetabolic sites had developed since the first examination, in several different locations (Figure 1, right panel).
Biopsy specimen. (A,B) H&E stainings showing architectural disturbance due to a medium-sized lymphoid population with a clear cell morphology. (C-F) Immunohistochemical stainings establishing the TFH origin of the abnormal cell population: CD3+, CD4+, CD10+ (not shown), ICOS+ (C), PD1 (D), BCL6 (E) and expression of CD30 (F). CD21 staining (G) shows an extended network of follicular dendritic cells. (H) Intermediate sized EBV+ immunoblasts by EBER in situ hybridization. Scalebar: 100 mum.
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F2
TFH cell markers (CD3, CD4, PD1, ICOS, BCL6, CXCL13) and a loss of CD7. The paracortical area contained an increased number of high-endothelial venules, supported by an increased number of follicular dendritic cell networks, with some foci of EBV+ B-cell immunoblastic proliferation in the background (Figure 2). These features highly suggested a diagnosis of AngioImmunoblastic T cell Lymphoma (AITL), pattern 2.