title: Intracystic papillary carcinoma of the breast: a diagnostic challenge with major clinical impact.
abstract: BACKGROUND
  Intracystic papillary carcinoma (IPC) is a ductal carcinoma of papillary variety that develops in a cystic space surrounded by a fibrous capsule. It is a rare clinicopathological entity, the in situ or invasive character of which is difficult to establish, particularly on biopsy. The treatment is surgical and breast conservation depends on the tumor size. Lymph node exploration is still debated. The diagnosis of IPC is a challenge for the pathologist: the negativity of the basement membrane markers and of myoepithelial cells carries a risk of over-diagnosis on biopsy that can lead to over-treatment.
  
  
  METHODS
  To illustrate this risk, we report the case of a breast mass of 8 cm; its biopsy evoked invasive papillary carcinoma (no hormone receptors and overexpression of Human Epidermal Receptor-2 (HER-2) and for which neoadjuvant chemotherapy associated with trastuzumab was firstly proposed.
  
  
  RESULTS
  The analysis of all anatomical radio-clinical data in a multidisciplinary context, however, allowed suspecting IPC, thus leading to first-line surgery (mastectomy with negative sentinel lymph nodes). With this diagnosis being confirmed on surgical specimen, no systemic treatment was then necessary. After 48 months, the patient is in complete remission.
authors.affiliation: Obstetrics and Gynecology Unit, Hospital Hautepierre-University Hospital, Strasbourg, France.
authors.forename: Cherif Y
authors.initials: CY
authors.lastname: Akladios
authors.affiliation: Breast Imaging Unit, Hospital Hautepierre-University Hospital, Strasbourg, France.
authors.forename: Marie-Noëlle
authors.initials: MN
authors.lastname: Roedlich
authors.affiliation: Breast Imaging Unit, Hospital Hautepierre-University Hospital, Strasbourg, France.
authors.forename: Marie-Françoise
authors.initials: MF
authors.lastname: Bretz-Grenier
authors.affiliation: Department of Pathology, Hospital Hautepierre-University Hospital, Strasbourg, France.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Croce
authors.affiliation: Breast Diseases Center, Hospital Hautepierre-University Hospital, Strasbourg, France karlicaro@noos.fr.
authors.forename: Carole
authors.initials: C
authors.lastname: Mathelin
mesh_terms: D001706:Biopsy; D001940:Breast / Q000473:pathology; D001943:Breast Neoplasms / Q000175:diagnosis*; D002291:Carcinoma, Papillary / Q000175:diagnosis* / Q000188:drug therapy; D005260:Female; D006801:Humans; D060828:Induction Chemotherapy; D008279:Magnetic Resonance Imaging; D008327:Mammography; D008875:Middle Aged; D016896:Treatment Outcome; D016217:Ultrasonography, Mammary
keywords: Intracystic papillary carcinoma; human epidermal receptor 2; overtreatment