case_images: PMC10867218_01
case_images: 1.1. The right colonic mass experienced a considerable decrease in its size from June to August 2021, with no longer evidence of liver or pancreatic infiltration 1.2. (A, B) Transmural full-thickness section of the rectum showing regression changes with no residual neoplasia. Normal mucosa and muscularis propia are coloured green and orange, respectively. The area showing regression changes is coloured in yellow. (C) Some areas of regression showed a mixture of lymphoid and macrophage infiltrates admixed in a collagenous residual stroma. (D) Numerous necrotizing granulomas with a rim of macrophages (>) were present.
case_images: fimmu-15-1352262-g001.jpg
case_images: PMC10867218_01_fimmu-15-1352262-g001.jpg
case_images: f1
case_images: After 4 cycles, the interval CT scan showed a remarkable response of the primary mass with no longer evidence of pancreatic or liver infiltration (cT3N1-2Mx;  Figure 1.1 ). No residual tumor foci were identified macroscopically or microscopically, consistent with a pathological complete response (pCR; ypT0, ypN0 [0/58]) to neoadjuvant treatment (Modified Ryan scoring of 0) ( Figure 1.2 ).
case_images: PMC10867218_02
case_images: A major radiologic response was observed with a clear reduction of the colonic neoplasm and no longer evidence of adjacent suspicious nodes between the basal CT scan and interval CT scan in August 2022. The green arrow represents the absence of lymph node after 5 cycles of pembrolizumab.
case_images: fimmu-15-1352262-g002.jpg
case_images: PMC10867218_02_fimmu-15-1352262-g002.jpg
case_images: f2
case_images: After 4 cycles, the interval CT scan showed a remarkable response of the primary mass and locoregional nodal disease (cT2N1Mx;  Figure 2 ).
case_images: PMC10867218_03
case_images: 3.1 (Case report 3) - The interval CT scan revealed an amelioration of the rectal and adnexal infiltration, with the apparition of a pyometra or a right-annex abscess that provokes an ipsilateral ureterohydronephrosis. A decrease in the abdominopelvic nodes was also observed. 3.2 (Case report 4) - The previously treated with radiofrequency 33-millimetre liver lesion in the right hepatic lobe showed no changes and a remarkable decrease is appreciated in the segment III metastasis, remaining the signs of the hepatic capsule and anterior abdominal wall infiltration. The green arrow indicates the location of the infiltrating liver lesion.
case_images: fimmu-15-1352262-g003.jpg
case_images: PMC10867218_04_fimmu-15-1352262-g003.jpg
case_images: f3
case_images: However, after eight cycles the second restaging scan showed an even better response ( Figure 3.2 ), and the patient was willing to undergo surgery, which was performed in October 2023.
case_images: PMC10867218_04
case_images: 3.1 (Case report 3) - The interval CT scan revealed an amelioration of the rectal and adnexal infiltration, with the apparition of a pyometra or a right-annex abscess that provokes an ipsilateral ureterohydronephrosis. A decrease in the abdominopelvic nodes was also observed. 3.2 (Case report 4) - The previously treated with radiofrequency 33-millimetre liver lesion in the right hepatic lobe showed no changes and a remarkable decrease is appreciated in the segment III metastasis, remaining the signs of the hepatic capsule and anterior abdominal wall infiltration. The green arrow indicates the location of the infiltrating liver lesion.
case_images: fimmu-15-1352262-g003.jpg
case_images: PMC10867218_04_fimmu-15-1352262-g003.jpg
case_images: f3
case_images: However, after eight cycles the second restaging scan showed an even better response ( Figure 3.2 ), and the patient was willing to undergo surgery, which was performed in October 2023.