A case of invasive micropapillary carcinoma of the breast involving extensive lymph node metastasis

We herein report a case of invasive micropapillary carcinoma (IMPC) involving extensive lymph node metastasis with no recurrence for over 7 years. A 41-year-old female presented with pain and a swelling mass in the left axillary region, which had been present for several months. The tumor measured 1.6 cm in diameter in the middle of upper area of the left breast. Based on the findings of a core needle biopsy the pathological diagnosis was IMPC or mucinous carcinoma. The cytology of the left axillary lymph node was positive for metastatic carcinoma. The patient underwent a left mastectomy and a left axillary dissection (level I to III). The postoperative pathological diagnosis was IMPC with mucin production, and the number of metastatic lymph nodes was 59. The patient was given adjuvant chemotherapy (four courses of 5-fluorouracil, epirubicin and cyclophosphamide (FEC) and four courses of docetaxel), radiation for the left chest wall, supraclavicular and internal thoracic area, and then received tamoxifen for 5 years. The patient has remained recurrence-free for over 7 years. IMPC is known to be an aggressive histological type associated with a high incidence of lymph node metastasis and a poor prognosis. It seems that long-term survival was obtained by performing sufficient medical treatment. Prognostic factors other than the number of lymph node metastases may also exist.