2023-04-052023-04-052020-01García, F.J.V., Carrión, N.P. y Cruz Merino, L.d.l. (2020). Long-term complete response to intrathecal trastuzumab in a patient with leptomeningeal carcinomatosis due to her2- overexpressing breast cancer: Case report. Medicine, 99 (1), e18298-5 p.. https://doi.org/10.1097/MD.0000000000018298.0025-79741536-5964https://hdl.handle.net/11441/143982Introduction: Leptomeningeal dissemination due to HER2-overexpressing breast cancer is a rare and hard to treat complication with short-term dismal prognosis. Patient concerns: A 34-year-old female previously treated because of HER2+ breast cancer is admitted to the Neurology Department in December 2016 due to sensory-motor neurological semiology. Diagnosis: A wide set of diagnostic tests is performed and finally cytologic findings after repeated CSF confirm leptomeningeal infiltration by breast carcinoma (panCK+, GATA3+). Interventions: Weekly intrathecal triple therapy with methotrexate, cytarabine and hydrocortisone plus trastuzumab is carried out during 4 months. Outcomes: Clinical and pathological response that lasts more than 24 months. Conclusion: Leptomeningeal carcinomatosis is an oncological situation where conventional therapies have limited activity. In HER2+ advanced breast cancer patients, intrathecal therapy with anti-HER2 therapy (trastuzumab) is feasible and may reach long-term disease control, especially in cases of low-tumor burden.application/pdfengAttribution-NonCommercial-NoDerivatives 4.0 Internacionalhttp://creativecommons.org/licenses/by-nc-nd/4.0/BreastCancerHER2IntrathecalLeptomeningeal carcinomatosisPositiveTrastuzumabinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccess10.1097/MD.0000000000018298