Papillary lesions of the breast encompass a broad range of entities with diverse morphologies. There are two main categories: papilloma and papillary carcinoma. Papillomas are benign neoplasms that can show secondary involvement by benign and malignant epithelial proliferations, whereas papillary carcinomas are epithelial malignancies that have an intrinsic papillary architecture. Recognition of the appropriate category helps to frame the diagnostic evaluation. We will examine the histologic distinction between papilloma involved by atypical hyperplasia/in-situ carcinoma and papillary carcinoma, and we will review the diagnostic features of papillary ductal carcinoma in-situ, encapsulated papillary carcinoma, invasive papillary carcinoma, and solid papillary carcinoma. In particular, we will evaluate the unique issues presented by encapsulated papillary carcinoma and solid papillary carcinoma in the assessment for stromal invasion and review current clinical guidelines for those entities.