case_images: PMC10834647_01
case_images: Case Pathology. (A-E) H&E stain of initial core biopsy of left cervical lymph node showing atypical lymphocytic infiltrate consisting of isolated large, pleomorphic, atypical lymphoid cells, including cells with features of Hodgkin/Reed-Sternberg cells (A), positive for CD30 (B), CD15 (C), strongly positive for PAX5 (D); with equivocal weak labeling for OCT2 (E). (F, J) H&E stain of core biopsy of subsequent left axillary lymph node showing similar-appearing atypical lymphoid cells in confluent sheets (F), positive for CD30 (G), CD15 (H), PAX5 (I), OCT2 (J). (A, F, X1000; B-E, H-J X400).
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case_images: By immunohistochemistry, the neoplastic cells were CD30+, CD15+, PAX5+, MUM1+, BCL6+, CD3-, CD5-, BCL2-, with a few cells positive for CD20, suggesting a differential diagnosis including cHL versus T-cell/ histiocyte-rich large B-cell Lymphoma ( Figure 1 ). Figure 1 ). Flow cytometry was unrevealing.
case_images: Coronal maximum-intensity-projection (MIP) images of 18F-FDG PET-CT at baseline post-treatment initiation interval at 69 days later and surveillance follow-up 629 days later. At +69 days post-treatment initiation there is significant decrease in splenomegaly (33.7 cm to 21.7 cm) and hepatomegaly (23.1 cm to 20.8 cm) with interval resolution of bulky FDG avid lymphadenopathy in the bilateral cervical and left axillary regions. The patient was treated with G-CSF prior to the 2nd panel image which likely explains diffuse osseous uptake which was noted. Follow-up examination >1.5 years later continues to show no evidence of disease.
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case_images: A repeat PET-CT revealed near complete resolution of abnormal FDG uptake and lymphadenopathy, with only residual mild lymphadenopathy in the left axilla and right inguinal regions, Deauville 2 ( Figure 2 ). Post-treatment PET-CT revealed resolution of FDG-avid adenopathy, Deauville 1, but new intense uptake in the gallbladder ( Figure 2 ).
case_images: Serum biomarker response. Depicts serum bilirubin levels (A) and lactate dehydrogenase (LDH) (B) noted on presentation and following administration of Brentuximab Vedotin (BV) on day 12 of admission.
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case_images: The course of laboratory findings, including serum bilirubin and trends are depicted in  Figure 3 .