Traditional Chinese Medicine Combined With Chemotherapy for Mammary Paget's Disease With Multifocal Heterogeneous Breast Cancer: A Case Report.

Mammary Paget's disease with ipsilateral multifocal, heterogeneous molecular subtype breast cancer is extremely rare and lacks diagnostic or therapeutic guidelines. Molecular subtype heterogeneity represents a major diagnostic and therapeutic challenge for this category of diseases. This case also involved treatment-related adverse events such as fatigue and insomnia. This paper reports the treatment process and final outcomes of a patient who received chemotherapy and radiotherapy combined with traditional Chinese medicine (TCM) for this rare condition. The patient presented with a left breast mass and eczematous changes of the nipple. She underwent surgical resection followed by chemotherapy and radiotherapy, after which she developed severe fatigue, insomnia, nausea, vomiting, palpitations, and chest tightness, which significantly affected her quality of life. The patient was diagnosed with mammary Paget's disease with ipsilateral multifocal breast cancer, T1cN1aM0, molecular subtyping exhibits inter-lesional heterogeneity: Estrogen Receptor (ER) (+), Progesterone Receptor (PR) (-), Human Epidermal Growth Factor Receptor 2 (HER2) (3+) and ER (-), PR (-), and HER2 (3+). The patient received standardized systemic treatment corresponding to the pathology of the mass, along with TCM therapies such as oral herbal medicine. After standardized treatment combined with TCM therapy, the patient's chemotherapy-related discomfort symptoms such as fatigue and sleep disturbances showed improvement during follow-up, and follow-up showed no obvious signs of recurrence or metastasis. Preoperative precise biopsy of all suspicious lesions should be performed. Stratified comprehensive treatment (targeted therapy, chemotherapy and radiotherapy, intensified capecitabine) should be tailored based on heterogeneous subtypes. In this single case, oral administration of TCM was associated with reported relief of adverse events such as fatigue and insomnia, suggesting its potential as an adjunctive supportive intervention. However, due to the uncontrolled, single-case design, causal efficacy cannot be inferred.