Intracystic papillary breast carcinoma

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Intracystic papillary carcinoma of the breast

  • AKA encapsulated papillary carcinoma of the breast, abbreviated EPC.

General

  • Very good prognosis[1] - it is similar to DCIS.
  • Classical menopausal women.
  • ~30% present with bloody discharge.[2]

Microscopic

Features:

  • Lesion confined to a cyst.
    • May have a thick fibrous capsule
    • The involved space is not lined by myoepithelial cells.
  • The cyst contains an abnormal epithelial proliferation with cribriform, solid or papillary architecture.
    • Loss of myoepithelial cells within the epithelial proliferation is a key feature.
    • Scattered large cells with pale eosinophilic cytoplasm may be observed[3].
      • These cells are so-called globoid cells or clear cells and are immunoreactive for GCDFP-15.
      • They should not be mistaken for myoepithelial cells.
    • Neoplastic epithelial cells:

IHC:

  • Calponin/p63/SMA/CK5-6
    • Loss of myoepithelial cells within the tumour.
    • Loss of myoepithelial cells at the cyst wall.
  • ER - Homogeneous staining of the epithelial proliferation.

Photos:

DDx[4][5]:

  • Intraductal papilloma.
    • Absent or scant stroma favors papillary carcinoma over papilloma.
    • Is there a single cell or dual cell population in the lesion?
      • ER staining will be heterologous in a benign lesion.
      • Myoepithelial markers (calponin/p63/SMA +ve)s hould be positive in a benign lesion.
  • Papillary ductal carcinoma in situ
    • Papillary DCIS shows myoepithelial cells (calponin/p63/SMA +ve) at the periphery of the involved spaces
    • But papillary DCIS should be negative for myoepithelial cells within the focus of DCIS
    • Papillary intracystic carcinoma does not show myoepithelial cells at the periphery of the involved spaces
  • Invasive papillary carcinoma of the breast
    • Similar architecture but no cystic space, frankly invasive.
    • Very rare.
  • Invasive carcinoma arising in association with papillary intracystic carcinoma
    • Epithelial entrapment in the encysting fibrous tissue should not be interpreted as invasion.
    • Carcinoma must be seen in the breast tissue outside the encysting fibrous tissue.
    • Infiltrating carcinoma is usually of the 'no special type' variety.
  • Adenoid cystic carcinoma of the breast
    • The solid variant looks basaloid - solid adenoid cystic carcinoma or a 'basal-like' carcinoma should be considered in these cases.

Notes

  • Many potential pitfalls with papillary breast lesions on needle core biopsy.
    • Complete excision is recommended[6].
  • Adequately and carefully sample the specimen to exclude an invasive component.
  • Report only the size of the invasive component (if present) to prevent over-estimation of tumor stage.

IHC

  • Loss of myoepithelial markers within the lesion.

References

  1. Rakha, EA.; Gandhi, N.; Climent, F.; van Deurzen, CH.; Haider, SA.; Dunk, L.; Lee, AH.; Macmillan, D. et al. (Aug 2011). "Encapsulated papillary carcinoma of the breast: an invasive tumor with excellent prognosis.". Am J Surg Pathol 35 (8): 1093-103. doi:10.1097/PAS.0b013e31821b3f65. PMID 21753694.
  2. Rodríguez, MC.; Secades, AL.; Angulo, JM. (Nov 2010). "Best cases from the AFIP: intracystic papillary carcinoma of the breast.". Radiographics 30 (7): 2021-7. doi:10.1148/rg.307105003. PMID 21057133.
  3. Collins, LC.; Schnitt, SJ. (Jan 2008). "Papillary lesions of the breast: selected diagnostic and management issues.". Histopathology 52 (1): 20-9. doi:10.1111/j.1365-2559.2007.02898.x. PMID 18171414.
  4. Collins, LC.; Schnitt, SJ. (Jan 2008). "Papillary lesions of the breast: selected diagnostic and management issues.". Histopathology 52 (1): 20-9. doi:10.1111/j.1365-2559.2007.02898.x. PMID 18171414.
  5. Pathmanathan, N.; Albertini, AF.; Provan, PJ.; Milliken, JS.; Salisbury, EL.; Bilous, AM.; Byth, K.; Balleine, RL. (Jul 2010). "Diagnostic evaluation of papillary lesions of the breast on core biopsy.". Mod Pathol 23 (7): 1021-8. doi:10.1038/modpathol.2010.81. PMID 20473278.
  6. Rizzo, M.; Linebarger, J.; Lowe, MC.; Pan, L.; Gabram, SG.; Vasquez, L.; Cohen, MA.; Mosunjac, M. (Mar 2012). "Management of papillary breast lesions diagnosed on core-needle biopsy: clinical pathologic and radiologic analysis of 276 cases with surgical follow-up.". J Am Coll Surg 214 (3): 280-7. doi:10.1016/j.jamcollsurg.2011.12.005. PMID 22244207.