mammary intraductal papilloma

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Definition: Intraductal proliferation of epithelial and myoepithelial cells overlying fibrovascular stalks.

Images

 http://webpathology.com/case.asp?case=280

Digital case

 JRC:5242 : Intraductal papilloma of the breast (intraductal papillomatosis).
 JRC:5244 : Intraductal papilloma of the breast (intraductal papillomatosis).
 JRC:5246 : Intraductal papilloma of the breast (intraductal papillomatosis) in male breast.
 JRC:5247 : Intraductal papilloma of the breast (intraductal papillomatosis).
 JRC:5252 : Intraductal papilloma of the breast (intraductal papillomatosis).
 JRC:5254 : Intraductal papilloma of the breast (intraductal papillomatosis).
 JRC:5255 : Intraductal papilloma of the breast (intraductal papillomatosis).
 JRC:5256 : Intraductal papilloma of the breast (intraductal papillomatosis).
 JRC:5257 : Intraductal papilloma of the breast (intraductal papillomatosis).

Macroscopy

 Well circumscribed, polypoid intraductal mass, usually @<@ 3 cm, soft, hemorrhagic
 Often infarcted

Microscopy

 Small, well-circumscribed polypoid nodules occur in a dilated duct.
 Multiple papillomatous nodules and stromal fibrosis.
 Papillary proliferation with irregular glandular spaces.
 Solid area consisting of both epithelial and myoepithelial cells.
 The stromal fibrosis can simulates invasive carcinoma.
 Multiple papillae in complex arborizing pattern with well-developed vascular connective tissue core surrounded by epithelial and myoepithelial cells
 Benign nuclei, frequent apocrine metaplasia, inflammation
 May arise within a large cystic duct, have comedo-type necrosis without DCIS (Ann Diagn Pathol 2004;8:276), rarely sebaceous metaplasia (Virchows Arch 2001;438:505)
 Infarcted cases may have squamous metaplasia or appear pseudoinfiltrative due to fibrosis (Hum Pathol 1984;15:764)
 Fibrosis at edge of papillomas may entraps glands and resemble invasion (Semin Diagn Pathol 2010;27:13)
 Glandular proliferation within stalks may resemble cribriform DCIS
 Needle biopsies can deposit clusters of benign cells in a distribution that resembles invasive carcinoma

Variants

 solid intraductal papilloma

• Fusion of papillary fronds creates secondary lumens.
• Myoepithelial cells are clearly seen at the periphery of the lumens

Differential diagnosis

 papillary DCIS

• delicate or absent fibrovascular core,
• often atypical nuclei
• or atypical mitotic figures,
• pseudostratification,
• usually no apocrine metaplasia;
• other DCIS may be present,
• 71% have no/incomplete myoepithelal layer,
• 76% are 34betaE12 negative,
• 67% are positive for neuroendocrine markers (Virchows Arch 2007;450:539)

 micropapillary DCIS
 invasive papillary carcinoma

• invasion into stroma,
• no myoepithelial layer

Links

 http://webpathology.com/case.asp?case=280

See also

 intraductal papillomatosis

Open references

 Diagnostic dilemmas in Intraductal papillomas of the breast - Experience at Sultan Qaboos University Hospital in the Sultanate of Oman. Aljarrah A, Malik KA, Jamil H, Jaffer Z, Sawhney S, Lakhtakia R. Pak J Med Sci. 2015 Mar-Apr;31(2):431-4. doi : 10.12669/pjms.312.6476 PMID: 26101505 (Free)