PMC2801466_01
Imaging Test Results: images from 3 different PET/CT scans are shown above. Images from the patient's initial study are on the left and show extensive abnormal areas of FDG activity on the coronal PET image and correlative CT and fused PET/CT images (inset left) of the large lesion in the liver. A second scan performed 30 days after the baseline scan shows complete resolution of the abnormal FDG activity (middle group of images) in all lesions after discontinuation of the patient's methotrexate. No other treatment was initiated. Note persistent low attenuation lesion in the liver (inset middle). Image on the right from a repeat scan 90 days later shows multiple new lesions, most of which were not even present on the initial scan.
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fig1
Initial PET/CT scan (Figure 1) showed widespread FDG-avid lymphadenopathy in the neck, axillae, upper abdomen, retroperitoneum, pelvis, and inguinal regions. PET/CT scan that was repeated at one month (Figure 1) and off MTX for 7 weeks showed dramatic decrease in all areas of lymphadenopathy, with complete resolution of abnormal FDG-uptake in his liver, bone, and lymph nodes. Despite the association of MTX-related LPDs and EBV-positivity, our EBV-negative patient showed dramatic reduction in disease burden with resolution of abnormal FDG-uptake on PET/CT after withdrawal of MTX as can be seen in Figure 1.
Pathology: (a) H and E section of liver core biopsy with dense infiltrate of small lymphocytes, original magnification 100X. (b) CD3 immunostain showing predominance of small T cells, original magnification 400X. (c) CD20 immunostain showing rare positive small B cells (arrows), original magnification 400X. (d) EBV encoded RNA in-situ hybridization (EBER), original magnification 400X. (e) H and E section of right axillary lymph node showing cluster of abnormal follicles, original magnification 100X. (f) CD21 immunostain showing intact but focally effaced follicular dendritic meshworks, original magnification 100X. (g) BCL6 immunostain showing many positive cells in follicles, original magnification 100X. (h) BCL2 immunostain with numerous negative cells in follicles, original magnification 100X. (i) H and E section of juxta-gastric lymph node demonstrating diffuse infiltrate of histiocytes and small and large lymphoid cells, original magnification 100X. (j) CD20 immunostain highlighting large lymphoid cells within infiltrate, original magnification 400X. (k) BCL6 immunostain showing scattered positive cells, including large lymphoid cells, original magnification 400X. (l) EBV encoded RNA in-situ hybridization (EBER), original magnification 100X.
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fig2
Repeat core liver biopsy (Figure 2) was also negative for malignant cells, showing a lymphoid infiltrate that lacked cytologic atypia. Immunostains showed predominantly CD3+ T cells with very rare CD20+ small B cells; EBV-encoded RNA in situ hybridization (EBER ISH) was negative (Figures 2(a)-2(d)). Immunostains showed that the large cells were BCL6+ BCL2-, and confirmed intact, although focally effaced, CD21+ follicular dendritic meshworks (Figures 2(e)-2(h)). Histologic sections demonstrated a diffuse infiltrate comprised of large CD20 positive B lymphoid cells in a background of histiocytes and small lymphocytes, scattered BCL6 + large lymphoid cells, and EBER ISH was negative (Figures 2(i)-2(l)).