case_images: PMC10285495_01
case_images: Rectal mucosa (A hematoxylin/eosin staining) and anal mucosa (B hematoxylin/eosin staining) infiltrated by squamous non-keratinizing carcinoma. Squamous differentiation underlined from p40 immunostaining (C p40 immunohistochemistry) and negativity for CDX2 (D CDX2 immunohistochemistry). Diffuse p16 immunostaining in neoplasia (E p16 immunohistochemistry).
case_images: fonc-13-1187623-g001.jpg
case_images: PMC10285495_01_fonc-13-1187623-g001.jpg
case_images: f1
case_images: Moreover, diffuse p16 immunostaining was shown, as observed in human papillomavirus (HPV) infection ( Figure 1 ).
case_images: Radiologic images. (A) The T2-weighted sequence of rectal cancer on the axial plane. Parietal neoplastic formation of the middle rectum with a polypoid appearance and a broad implant base is observed on the right posterolateral wall from 6 to 12 o'clock, which causes the narrowing of the rectal lumen. This rectal formation infiltrates the mesorectum until it exceeds the mesorectal fascia by about 4.5 mm and infiltrates the elevator muscle. (B) The T2-weighted sequence of anal cancer on the axial plane. At the level of the rectal junction at 11 o'clock, there is evidence of neoplastic tissue infiltrating the internal and external anal sphincter. (C) Sequence weighted in DWI in correspondence with the rectal lesion. Signal restriction in the DWI sequence. (D) Sequence weighted in DWI at the level of the anal canal. Signal restriction in the DWI sequence. (E) Coronal plane T2-weighted sequence. A clear hypointensity is observed with regard to fibrotic outcomes 6 months after the start of radiochemotherapy (CRT). (F) T2-weighted sequence on the axial plane. Anal lesion response after CRT. (G) Sequence weighted in DWI in correspondence with the rectal lesion. No signal restriction following CRT. (H) Sequence weighted in DWI at the level of the anal canal. No signal restriction following CRT.
case_images: fonc-13-1187623-g002.jpg
case_images: PMC10285495_01_fonc-13-1187623-g002.jpg
case_images: f2
case_images: Finally, re-evaluation with contrast-enhanced MRI examination showed complete tumor regression with no sign of a viable tumor in the DWI sequence ( Figure 2 ).