title: Encapsulated papillary carcinoma of the breast: an invasive tumor with excellent prognosis.
abstract: Papillary carcinoma (PC) of the breast, which accounts for 0.5% to 1% of breast cancer, is a distinct histologic subtype that is characterized by malignant epithelial proliferation supported by fibrovascular stalks. However, the classification of PC (whether they are in situ or invasive), its behavior, and management remain a matter of debate.
  
  
  METHODS
  In this study, we reviewed 302 PCs including 247 pure PCs without coexisting conventional non-PCs collected from 3 institutions. This included 208 (84%) intracystic PCs (IPC), 30 (12%) solid PCs (SPC), and 9 (4%) papillary ductal carcinoma in situ (DCISs). In addition, previous studies of PC were reviewed. This included 339 pure PCs of a total of 521 PC patients. Clinical and outcome analyses were carried out to assess nature and behavior of these lesions and to determine their optimal outcome-based management.
  
  
  CONCLUSIONS
  SPC is more frequently associated with coexisting conventional invasive carcinoma than IPC (P<0.05). Although the majority of papillary DCIS and some cases of IPC and SPC (both called encapsulated PC) that are surrounded by an intact layer of myoepithelial cells are considered to be true in situ lesions, PC lacking a peripheral layer of myoepithelial cells can be regarded as a special type of invasive carcinoma associated with low incidence of stromal/skeletal muscle invasion, low frequency of lymph node metastasis (3%), and infrequent development of local or distant recurrence. These lesions are therefore characterized by indolent behavior and extremely favorable prognosis. Encapsulated PC can be treated with adequate local therapy. Routine use of adjuvant therapy, particularly chemotherapy, is clearly not appropriate in view of the very low risk of subsequent events. However, hormonal therapy may be indicated in certain cases such as recurrent PC.
authors.affiliation: Department of Histopathology, Nottingham University Hospitals NHS Trust, City Hospital Campus, Nottingham, UK. emadrakha@yahoo.com
authors.forename: Emad A
authors.initials: EA
authors.lastname: Rakha
authors.forename: Nirav
authors.initials: N
authors.lastname: Gandhi
authors.forename: Fina
authors.initials: F
authors.lastname: Climent
authors.forename: Carolien H M
authors.initials: CH
authors.lastname: van Deurzen
authors.forename: Syeda Asma
authors.initials: SA
authors.lastname: Haider
authors.forename: Louisa
authors.initials: L
authors.lastname: Dunk
authors.forename: Andrew H S
authors.initials: AH
authors.lastname: Lee
authors.forename: Douglas
authors.initials: D
authors.lastname: Macmillan
authors.forename: Ian O
authors.initials: IO
authors.lastname: Ellis
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D001943:Breast Neoplasms / Q000145:classification / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000145:classification / Q000401:mortality / Q000473:pathology* / Q000556:secondary / Q000628:therapy; D002291:Carcinoma, Papillary / Q000145:classification / Q000401:mortality / Q000473:pathology* / Q000556:secondary / Q000628:therapy; D018572:Disease-Free Survival; D004847:Epithelial Cells / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D009626:Terminology as Topic; D013997:Time Factors