Papillary carcinomas of the breast are far from being uncommon and are often puzzling or difficult to handle lesions. They encompass a wide variety of possible diagnostics, ranging from clearly in situ lesions (papillary ductal carcinoma in situ or colonizing a papilloma) to frankly invasive lesions (invasive papillary carcinoma), with intermediate forms of uncertain invasive potential often associated to a very good prognosis (encapsulated papillary carcinoma, solid papillary carcinoma). The diagnosis is based on a mandatory phenotyping, using myoepithelial markers in particular, bearing in mind that the absence of myoepithelial cells does not necessarily imply invasiveness. Diagnosis should be cautious on biopsy specimen, and the sampling extensive on the surgical specimen. These lesions are usually estrogen receptor positive, but rare forms of triple negative phenotype do exist. Lastly, some special type of invasive carcinoma may present with a papillary pattern (tall cell carcinoma with reverse polarity, secretory carcinoma, lobular papillary carcinoma). (c) 2026 Elsevier Masson SAS. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
