PMC8185331_01
Pretreatment CT images. (A, B) CT arterial and portal phase images of liver metastasis with a size of 70 mm x 61 mm, respectively. (C, D) CT arterial and portal phase images of abdominal & pelvic cavity metastasis with a size of 76 mm x 50 mm, respectively.
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The computed tomography (CT) revealed metastasis in the liver and abdominal & pelvic cavity ( Figure 1 ).
Histopathology of rectosigmoid-junction SCC cancer and immunohistochemistry. (A) H & E stain, original magnification x200. (B) PD-L1 immunohistochemistry (antibody Dako 22C3), original magnification x200.
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Biopsy was performed, and the pathology of the specimen revealed SCC ( Figure 2A ). Immunohistochemistry (IHC) showed a strong positive expression of PD-L1 in tumor cells ( Figure 2B ).
Immunohistochemistry of MMR proteins. The tumor cells preserved expression of MLH1 (A), MSH2 (B), PMS2 (C), and MSH6 (D); original magnification x200.
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IHC method was used to confirm that the patient had pMMR rectosigmoid-junction SCC cancer ( Figures 3A-D ). In
Treatment of rectosigmoid-junction SCC cancer. (A) Timeline of the clinical course in this patient. (B, C) CT scan showed a partial response in liver metastasis (40 mm x 27 mm) from arterial and portal phase images. (D, E) CT scan showed a partial response in abdominal & pelvic cavity metastasis (32 mm x 18 mm) from arterial and portal phase images.
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April 28, 2020, the patient was received Sintilimab, a PD-1 antibody (200 mg on D1, every 3 weeks) ( Figure 4A ). And on May 12, 2020, the chemotherapy was added (Capecitabine 1.5 g, twice a day on D1-D14, every 3 weeks). About three months later, a partial response was confirmed in the CT scan ( Figures 4B-E ) and lasted until January 6, 2021.