Science and Education Publishing American Journal of Medical Sciences and Medicine 2327-6657 5 1 2017 4 13 Invasive Papillary Carcinoma of the Breast Presenting after Metastatic Mucinous Adenocarcinoma: Report of a Rare Case 20 22 EN Mazaher Ramezani Farhad Kavousi Setareh Afzali Masoud Sadeghi Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran AJMSM2017513 10.12691/ajmsm-5-1-3 2016 11 20 2017 3 19 2017 4 11 Breast cancer constitutes a heterogenous group of lesions. Invasive papillary carcinoma of the breast is a rare form of breast cancer with less aggressive behavior which may have mucinous differentiation. Histologically papillary projections with fibrovascular core and epithelial proliferation are present. Signet ring morphology and extracellular mucin production can be seen but myoepithelial cells are absent. We reported a case of invasive papillary carcinoma of the breast in a 74-year-old lady without mucin production, which first presentation was a metastasis of unknown origin to the spinal column as adenocarcinoma with mucin production. In conclusion, although invasive papillary carcinoma of the breast is known as a less aggressive tumor, but its presentation may be with metastasis and mucin production, despite of non-mucinous primary tumor.