Abstract

Lymphangitic carcinomatosis (LC) represents a rare and challenging manifestation of metastatic breast cancer, often associated with poor prognosis and limited treatment options. HER2-positive breast cancer subtype accounts for a significant proportion of metastatic cases, and targeted therapies, such as trastuzumab and pertuzumab, have demonstrated clinical benefit. However, patients with LC require alternative strategies to address the unique challenges posed by this aggressive form of metastasis. We present a case report of a 48-year-old female diagnosed with HER2-positive metastatic breast cancer complicated by LC. In this report, we detail the comprehensive treatment approach utilizing a triple HER2-blockade regimen consisting of lapatinib, trastuzumab, and pertuzumab. The patient’s clinical course, radiographic findings, and treatment response are discussed. The patient exhibited clinical improvement, with reduced dyspnea, stabilization of her pulmonary symptoms, and improved quality of life after initiating the triple HER2-blockade regimen. Radiographic assessments revealed decreased tumor burden within the lung lymphatics. The treatment was generally well-tolerated, with manageable side effects. This case report highlights the potential of a triple HER2-blockade strategy in managing HER2-positive metastatic breast cancer with LC. While further research and larger clinical trials are necessary to confirm the efficacy of this approach, our case suggests that it may offer a promising option for patients with limited treatment choices in this challenging clinical scenario. The findings underscore the importance of individualized treatment plans and ongoing research in optimizing therapies for metastatic breast cancer, particularly in cases complicated by LC.