Aggressive behavior of Her-2 positive colloid breast carcinoma: A case report in a metastatic breast cancer

Abstract Introduction Colloid breast carcinoma is a rare form of invasive ductal cancer characterized by large amount of mucous deposition. It is considered as an indolent cancer that usually affects older women. Colloid breast carcinoma generally expresses estrogen and progesterone receptors but negative for Her-2. Recommended surgery and adjuvant treatment of colloid breast carcinoma is not well-established. Presented case A 46 years-old woman presented as an aggressive colloid breast carcinoma showing skin ulceration, enlargement of multiple axillary lymph nodes and a metastasis in the pleura at diagnosis. The primary tumor showed strong positive expression of estrogen, progesterone as well as Her-2 receptors. The patient was treated with 6 cycles of paclitaxel and carboplatin followed by mastectomy, radiotherapy, and hormonal therapy. Patient tolerated the treatment course and showed improvement both in the locoregional control and pleural metastasis. Discussion Colloid breast carcinoma with aggressive clinical course is rarely found. Nodal involvement as a sign of poor prognosis in colloid breast carcinoma ranges only between 12 and 19%. Therefore, axillary node clearance is usually excluded during the surgery of colloid breast carcinomas. However, in the presence of high-risk characteristics, mastectomy involving axillary lymph node dissection is still contentious. In patients with Her-2 overexpression, treatment using anti-Her2 (trastuzumab) is also still disputed in colloid breast carcinoma because of the higher resistance rates. Conclusion Although clinically aggressive colloid breast carcinoma is rare, thorough clinical assessment and immediate treatment initiation will be beneficial for patients with high risk of relapse and metastatic spread.