case_images: PMC10517634_01
case_images: Primary anal canal lymphoma successfully treated with R-CHOP chemotherapy. (A) An ulcerative fungating mass covered with dirty exudate on the rectum and anus, which was observed at diagnosis. (B) Hematoxylin and eosin staining (x200); photomicrograph shows a large atypical pleomorphic lymphocytic nucleus with multiple nucleoli. (C) CD20 immunostaining positive (x100). (D) CD3 immunostaining negative (x100). (E) Computed tomography shows a mass encircling the rectum with mesorectal lymph node (arrow). (F) Whitish scars on the rectum and anus, which were observed 6 months after treatment. R-CHOP, rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone.
case_images: goad058f1.jpg
case_images: PMC10517634_01_goad058f1.jpg
case_images: goad058-F1
case_images: Colonoscopy revealed an ulcerative fungating mass with a soft margin that extended from the anal rim to the rectum, measuring ~5 cm on the anal canal (Figure 1A). Histologic examination of the biopsy samples revealed a diffuse proliferation of large atypical lymphoid cells with a high nuclear-cytoplasmic ratio, coarse chromatin, and prominent nucleoli (Figure 1B). The immunohistochemical staining results were as follows: positive for CD20 (Figure 1C), BCL2, MUM1, and c-MYC (moderate intensity, ~50%) and negative for CD3 (Figure 1D), CD10, and BCL6. Chest computed tomography (CT) revealed no evidence of lymphoma, and enhanced abdominal/pelvic CT and magnetic resonance imaging showed a mass encircling the rectum and enlarged regional LNs (Figure 1E). Subsequent CT and colonoscopy with a biopsy of the lesion revealed that the mass had completely disappeared (Figure 1F).