PMC8184241_01
Enhanced computed tomography (CT) reveal one irregular hypoattenuating mass, 4.6x3.7 cm in size with unclear margins, involved the spleen vessels and located at the pancreatic tail. (A) Arterial phase showed inhomogeneous enhancement of the lesion, (B) the portal venous phase showed a mass with ring enhancement, (C) in the delay phase, the ring enhancement of the lesion gradually de-enhanced, (D) the mass with ring enhancement in coronal view.
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Enhanced computed tomography (CT) demonstrated a complex hypoattenuating mass with the size of 4.6x3.7 cm and unclear margins, involving the spleen vessels at the pancreatic tail (Figure 1).
Preoperative MRI and PET/CT examination of the reported case. (A) The lesion of liver (one in the S6 of liver, another in the S8, white arrow) was hypointense in T1-weighted imaging. (B) The irregular lesion (white arrow) has slightly hyperintense in T2-weighted imaging, (C) significantly enhanced lesions in the arterial dominant phase, (D) PET/CT presented hypermetabolic nodule measuring 2.3x1.4 cm (SUVmax=6.2) in pancreatic tail.
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Meanwhile, liver lesions appeared as hypointense on T1-weighted image and as hyperintense on T2-weighted image with ring enhanced during the arterial dominant phase of contrast-enhanced MRI, and metastatic lesions could not be excluded (Figure 2A-C). Whole-body 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT examination revealed a moderate FDG uptake nodule with the size of 4x4.5 cm in front of the pancreatic tail (SUVmax 6.2) and mild FDG uptake nodules in the liver (SUVmax 2.1 and 3.05) with normal scans of the head, neck, chest, and colon (Figure 2D).
(A and B) Hematoxylin and eosin (H&E) staining revealed the tumors consisted of epidermoid cells, intermediate undifferentiated cells, and mucous cells. (C-F) Immunohistochemical studies show positivity for P40 (Anti-P40 Antibody, MABS519-AF647), CK7 (Anti-Cytokeratin-7antibody, SAB5600093), P63 (Anti-P63 Antibody, HK5257) and AB-PAS (AB-PAS staining kit, HZ-0127), respectively.
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Detailed postoperative pathological examination was performed and it was found that the carcinoma cells consisted of epidermoid cells, intermediate undifferentiated cells and poorly differentiated adenocarcinoma cells with mucous cells in cytoplasm of tumor cell (Figure 3A and B). Immunohistochemical findings indicated that the pancreatic tumor was strong staining with antibodies to P53, CA199, CEA, CK19, CK7, P63, P40 and revealed negative staining for CK20, CD56, CgA, Syn (Figure 3C-F).
(A and B) Targeted-gene sequencing showed PD-L1 expression in pancreatic tumor. (C) Isotype-matched monoclonal antibodies were used for control staining and to confirm that the specificity of primary antibody binding. (D) Targeted-gene sequencing showed the quantity of tumor mutation burden (TMB).
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The patient had a TMB of 5.6 muts/Mb (Figure 4D), which is higher than PDAC (approximately 1.0 muts/Mb). Tumor proportion score (TPS) and combined positivity score (CPS) were calculated to evaluate the immunohistochemical expression of PD-L1 based on 22C3 assays and detected in 15% and 8 of the cases, respectively (Figure 4A-C). (This work was accomplished by the OrigiMed biotechnology company) 