A 50-year-old woman with a BRCA1 mutation was diagnosed with triple-negative carcinoma of the left breast in 2022. To initiate neoadjuvant chemotherapy, a totally implanted subclavian catheter was inserted. After three months of use, it developed a thrombosis and had to be removed. A second catheter was then inserted into the left brachial vein. Immediately after placement, the patient developed cellulitis in the left upper limb, which resolved following treatment with flucloxacillin. Three months later, drainage of a whitish fluid through the catheter was observed (A). Analysis confirmed it was lymph, likely due to displacement into the thoracic duct insertion at the left subclavian vein (B). The catheter was removed. The patient subsequently underwent mastectomy, adjuvant capecitabine, and is currently under surveillance. This case highlights the potential complications of implanted catheters in oncology patients, including thrombosis, infection, and, less commonly, lymphatic migration – all of which can delay cancer treatment.