What does a mass at colectomy site mean after colon cancer surgery?

Status post near total colectomy with a left lower quadrant ileocolic anastomosis and right lower quadrant diverting ileostomy. There is a large soft tissue mass in the left lower quadrant at the prior colectomy site invading the abdominal wall. This mass also appears to invade the adjacent loop of small bowel, likely jejunum, with small foci of extra luminal air identified within the mass/adjacent to the jejunum. The previously seen abscess along the left pelvic sidewall has been drained in the interim, the pigtail drain is in satisfactory position, no residual fluid collection is seen. Narrative INDICATION: Malignant neoplasm of descending colon COMPARISON: January 7, 2026 and January 5, 2026 TECHNIQUE: Volumetric multidetector CT images of the abdomen and pelvis were obtained following the administration of IV contrast. Multiple planes were reconstructed for examination. FINDINGS: Emphysema. Minimal basilar atelectasis. Normal heart size. There is no pericardial or pleural effusion. The liver is normal in size. The hepatic and portal veins are patent. Unremarkable gallbladder and common bile duct. Unremarkable adrenal glands, spleen and pancreas. Normal right kidney. There is a punctate nonobstructing stone in the inferior left kidney. No hydronephrosis, renal mass or perinephric stranding. Unremarkable stomach and small bowel. Status post near total colectomy, with an ileocolic anastomosis in the left lower quadrant. There is a diverting ileostomy in the right lower quadrant. Redemonstrated is a large infiltrative soft tissue mass in the left lower quadrant, invading the anterior abdominal wall and pelvic sidewall. The mass like extends through all 3 layers of the abdominal wall musculature. The exact borders of the lesion are difficult to delineate. This mass measures approximately 5.7 x 6.3 cm in the axial plane (series 2 image 65) and 9 cm craniocaudally. This mass likely invades the loop of small bowel passing immediately medial to it, with a few small foci of extra luminal air identified (series 2 image 62). There is a percutaneous pigtail drain anterior to the left iliacus muscle. No significant residual fluid collection is identified. The second fluid collection superior and posterior to the left ilium has resolved in the interim. Unremarkable urinary bladder, prostate and seminal vesicles. Status post inguinal hernia repair with mesh. There are a few subcentimeter left external iliac lymph nodes. No further abdominal or pelvic lymphadenopathy is identified. There is no ascites. No gross free air. No destructive osseous lesion is seen. There are no acute osseous findings.