[A Case of Rectal Cancer with Left Axillary Lymph Node Metastasis]

Metastasis to axillary lymph nodes from gastrointestinal malignancies is rare and has been infrequently reported. We report a case of rectal cancer with metastasis to the left axillary lymph nodes. The patient was a 61-year-old woman who visited her local doctor with the chief complaint of abdominal pain. She was prescribed laxatives; however, there was no improvement and she presented to our emergency department for vomiting. Contrast-enhanced CT of the abdomen showed irregular wall thickening of the rectal Rs with contrast enhancement and dilation of the mouth side of the intestine. Multiple large lymph nodes were also observed near the lesion, around the inferior mesenteric artery, and in the para-aortic region. This suggests multiple lymph node metastases from rectal cancer. In addition, a calcified nodule was observed on the dorsal surface of the uterus, along with an ascites effusion, leading to the suspicion of a disseminated nodule. The patient underwent urgent colonic stenting for bowel obstruction due to rectal cancer. Although the patient was being considered standby for rectal cancer resection followed by chemotherapy, preoperative chest CT showed multiple enlarged lymph nodes in the left axilla, left pectoral interstitium, subpectoralis minor, and left supraclavicular fossa, as well as a mass lesion in the left mammary CD region, leading to the suspicion of breast cancer with lymph node metastasis. Fine-needle aspiration cytology of the axillary lymph nodes was consistent with a Class Ⅴ breast cancer origin, but core needle biopsy of the mass lesion in the left mammary gland showed no evidence of malignancy. Therefore, axillary lymph node metastasis was considered to originate from negative breast cancer or unknown primary or rectal cancer. Laparoscopic low anterior resection, D2 dissection, and biopsy of the left axillary lymph node were performed for rectal cancer obstruction and Stage Ⅳ. Pathological results showed that the morphology of the adenocarcinoma in the left axillary lymph node was similar to that of the colorectal cancer lesion, and immunostaining results were consistent with lymph node metastasis in colorectal cancer. Based on the above, a diagnosis of rectal cancer Rs with left axillary lymph node metastasis(pStage Ⅳ)was made, and postoperative chemotherapy was started from the 5th week. Chemotherapy is currently ongoing 6 months after surgery.