EP830 - Arterial tumor embolism in patient with Stage IV rectal adenocarcinoma

Purpose/Background: Acute limb threatening ischemia from arterial tumor embolus is a rare complication, with limited case reports in the literature. Most publications on tumor emboli focus on pulmonary involvement, with significantly fewer addressing peripheral arterial events. This case report presents a patient with rectal adenocarcinoma, status post low anterior resection, who developed an acute peripheral arterial occlusion from a metastatic adenocarcinoma embolus.

Methods/Interventions: The patient was a 64-year-old male with a history of rectal adenocarcinoma with lung metastasis extending to pulmonary vein on chemotherapy. He had a history of locally advanced rectal cancer TNM ypT3N1aM0 status post neoadjuvant chemotherapy and low anterior resection (LAR) with diverting loop ileostomy. Postoperatively, he developed an anastomotic leak requiring transanal drains. Two years later, he underwent parastomal hernia repair and ileostomy closure.

His medical history included COPD, hypertension, anxiety, insomnia, CHF, CVA, DVT, renal and splenic infarcts (likely embolic), atrial fibrillation (on therapeutic lovenox), NSTEMI (not a candidate for angioplasty), and chemotherapy-induced cardiomyopathy. He was a heavy smoker (40+ pack-years).

A few years after LAR, he was diagnosed with lung metastasis from rectal cancer without any evidence of local recurrence in the pelvis. He was treated with multiple lines of chemotherapy and chemoradiation for lung metastasis. Eventually he started treatment with Stivarga. The patient had significant worsening of quality of life from low anterior resection syndrome and was considering surgical conversion to an end colostomy. While he was off chemotherapy, he developed distal right brachial artery occlusion secondary to tumor embolus from metastatic adenocarcinoma, requiring thromboembolectomy. Intraoperatively, the tumor embolus was white, soft, spongy and frozen section revealed adenocarcinoma.

Results/Outcomes: Tumor thrombus revealed adenocarcinoma on final pathology consistent with colorectal primary source. Patient's right brachial artery was cleared of thrombus with embolectomy. There were no further signs of limb ischemia. He shortly discharged from the hospital and continued with his chemotherapy treatments.

Conclusion/Discussion: Peripheral arterial tumor embolism is a rare manifestation of metastatic rectal cancer and should be considered in patients with advanced malignancy presenting with acute limb ischemia. Although rare, tumor embolism represents a potential complication when chemotherapy is paused for surgical planning. This case aims to raise awareness of this phenomenon and underscores the need for further research to better understand its mechanisms and identify strategies for prevention, especially due to increased number of patients on chemotherapy for unresectable disease.