Case ReportMetaplastic breast carcinoma “fibromatosis like”, associated with intraductal papilloma. Case report and literature review

The “fibromatosis like” phenotype is a rare tumor and represents just 1% of breast carcinomas. It is classified into a large group of heterogeneous metaplastic carcinomas. Due to its innocent and harmless histology it is often obscured and represents a considerable diagnostic challenge, especially in fine needle biopsy. “Fibromatosis like” variant shows a subtle proliferation of spindled cells with scanty nuclear atypia an eosinophilic cytoplasm.Besides this mesenchymal proliferation it's feasible to find a second “epithelial type” element (squamous, glandular) that grants the metaplastic nature of the lesion. In many cases the neoplasia mimics breast benign fibromatous changes or reactive spindle cells post puncture that may be misleading to a misdiagnosis.There are many hypothesis concerning the possible relationship between the papillary lesions and the development of metaplastic carcinoma, however the scientific opinion is inconsistent.