RESUMO
We report the case of a woman with metastatic breast cancer receiving intrathecal trastuzumab (and intravenous trastuzumab for more than 7 years). She was diagnosed in 2001 with a duct invasive breast cancer T3N1M0 HER2 (human epidermal growth factor receptor 2)-positive +++ HR (hormone receptor) -negative. She received chemotherapy and then she had a mastectomy. Several metastases were discovered and treated from 2003 to 2008 with chemotherapy. In March 2010, brain metastases and a leptomeningeal carcinomatosis from her HER2-positive breast cancer appeared. From that moment on she received intravenous trastuzumab (6 mg/kg) every 3 weeks, intrathecal trastuzumab (21 mg) weekly for 16 injections and lapatinib. Intrathecal trastuzumab was stopped because of cerebrospinal fluid (CSF) clearing. Intrathecal trastuzumab was injected again from December 2013 for 14 injections. The relevance of treating leptomeningeal carcinomatosis with intrathecal trastuzumab administration is shown through this case report.