What happened, in summary

This 72-year-old man had Stage IIIA non-small cell lung cancer, classified as cT4N0M0. He was treated with 4 courses of cisplatin plus docetaxel chemotherapy together with radiation therapy, delivered as 60 Gy in 30 fractions. After that combined treatment, he received 1 year of consolidation durvalumab at 640 mg/body. The lung cancer responded completely, with no visible disease on imaging. Thirteen months after that complete response, routine surveillance CT found a new solitary nodule in the mesorectum, the tissue around the rectum. The 15 mm lesion raised concern because PET imaging showed FDG uptake. Colonoscopy, urine tests, and tumor markers did not identify another cancer source, and markers including CEA, SLX, squamous cell carcinoma antigen, neuron-specific enolase, CYFRA, and progastrin-releasing peptide were normal. Because the nodule was difficult to biopsy safely, the team chose laparoscopic-assisted removal to make a diagnosis. During surgery, the rectum was mobilized, the lesion was removed with surrounding rectal tissue, and bowel continuity was restored. Pathology showed that the 7 mm white nodule was not cancer. It was an intravenous organized thrombus surrounded by granulation tissue, with no malignancy. He recovered well after surgery. A mild postoperative D-dimer elevation resolved without anticoagulation. During 16 months of follow-up, there was no radiologic evidence of lung cancer recurrence and no further thromboembolism. The finding was important because the PET-avid nodule could have changed his cancer status, but surgical pathology showed a non-cancer clot instead after careful removal. He avoided unnecessary systemic cancer treatment escalation for presumed recurrence.