Original ArticlesSolid Papillary Breast Carcinomas Resembling the Tall Cell Variant of Papillary Thyroid Neoplasms A Unique Invasive Tumor With Indolent BehaviorFoschini, Maria P. MD*; Asioli, Sofia MD*; Foreid, Susan MD†; Cserni, Gabor MD‡; Ellis, Ian O. MD, FRCPath§; Eusebi, Vincenzo MD, FRCPath*; Rosai, Juan MD, FRCPath∥Author Information *Department of Biomedical and Neuromotor Sciences, Section of Pathology “M. Malpighi,” University of Bologna, Bologna ∥Department of Pathology, CDI, Milano, Italy †Pathology Unit, Laboratories Dr. Macedo Dias, Porto, Portugal ‡Department of Pathology, Bács-Kiskun County Teaching Hospital, Kecskemét, Hungary §Department of Histopathology, Nottingham City Hospital, Nottingham, United Kingdom The study was supported with grants from the University of Bologna (Fundamentally Oriented Research Funds) and ASAN Onlus, Bologna. This study (Gábor Cserni) was partially funded by the National Research, Development and Innovation Office grant GINOP-2.3.2-15-2016-00020. Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article. Correspondence: Maria P. Foschini, MD, Department of Biomedical and Neuromotor Sciences, Section of Pathology “M. Malpighi,” University of Bologna, Via Altura n. 3, Bologna 40137, Italy (e-mail: [email protected]). The American Journal of Surgical Pathology: July 2017 - Volume 41 - Issue 7 - p 887-895 doi: 10.1097/PAS.0000000000000853 Buy Metrics Abstract Thirteen cases of invasive solid papillary breast carcinomas resembling the tall cell variant of papillary thyroid neoplasms (BPTC) are reported here. Some cases had long-term follow-up. BPTC is a special type of primary breast neoplasm showing a triple-negative profile but low aggressive potential. Knowledge on BPTC is still scanty; therefore, the aim of the present paper was to report on the features of an additional 13 cases. All the patients were female individuals, and the mean age at presentation was 62.6 years; nodule sizes ranged from 0.6 to 2.5 cm (average, 1.6 cm). All the cases were characterized on histology by papillary, follicular as well as solid structures. The cells were columnar, eosinophilic mostly with granular cytoplasms, rich in mitochondria, with the features of oncocytes in no fewer than 7 cases. Estrogen and progesterone receptors as well as HER2 were consistently negative. The Ki67 proliferative index was low. Markers consistent with thyroid origin, such as TTF1 and thyroglobulin, were negative. Five cases stained for mammoglobin and GATA 3 were positive. All cases proved to be invasive and 2 cases each experienced metastases to 1 lymph node (axillary and intramammary). One case of the latter had a local recurrence. Nevertheless, all the patients are alive, free of disease 24 to 132 months after surgery, of which 8 are without further treatment The present series confirms that BPTC is a primary breast tumor of low malignant potential. Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.