In the Dukes-Astler-Coller (MAC) classification of colorectal cancer, a tumor that penetrates through the bowel wall into pericolic fat and has positive regional lymph nodes corresponds to:

• A MAC B2
• B MAC C1
• C MAC D
• D MAC C2 ✓

Explanation

In the Modified Astler-Coller classification: B2 = penetration through full bowel wall with no lymph node involvement; C1 = lymph node involvement with tumor limited to within the wall; C2 = lymph node involvement with tumor that has penetrated the full bowel wall (through all layers into pericolic/perirectal fat). Stage D indicates distant metastasis. This patient (full-wall penetration + positive nodes) is MAC C2.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

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Written and medically reviewed by the StethoPrep medical team.