A 30-year-old woman presented to an outside hospital with pain in the right upper abdomen. Imaging revealed over 100 liver lesions, the largest measuring 74 mm×71 mm, and multiple lytic bone lesions. An outpatient liver biopsy showed a poorly differentiated adenocarcinoma favouring a breast primary. The tumour was oestrogen and progesterone receptor negative, but human epidermal growth factor 2 (HER2/neu) amplified. In her second clinic visit she had decompensated liver failure manifested by new-onset ascites and jaundice. Initially, the chemotherapy plan was for docetaxel, pertuzumab and trastuzumab, but given her severe liver dysfunction we used a combination of carboplatin, pertuzumab and trastuzumab as an inpatient. She was hospitalised for 14 days and eventually discharged with a marked improvement of her symptoms and liver tests. She subsequently completed five outpatient chemotherapy cycles. We showed that carboplatin is a possible alternative to docetaxel when severe liver dysfunction precludes docetaxel's use in combination with pertuzumab and trastuzumab.