Breast-nonmalignant - Sclerosing adenosis

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Breast-nonmalignant

Sclerosing adenosis of breast

Author: Nat Pernick, M.D. (see Authors page)

Revised: 9 October 2012, last major update - March 2010

Definition

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● Low power diagnosis of increase in glandular elements plus stromal proliferation that distorts and compresses glands

● Preservation of luminal epithelium and peripheral myoepithelium with surrounding basement membrane

Terminology

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Adenosis tumor/nodular adenosis:

● Palpable mass (AJR Am J Roentgenol 2000;175:31)

Myoepitheliosis:

● Rare; sclerosing adenosis with predominance of myoepithelial cells, presents as multifocal microscopic lesions (AJSP 1991;15:554)

● Cells may have longitudinal nuclear grooves

Epidemiology

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● Mean age 30 years

Sites

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Etiology

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Clinical features

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● Increased risk of cancer of 1.5 to 2x (Cancer 1989;64:1977); also coexists with cancer

● Rarely involved by LCIS and mistaken for invasive carcinoma (Mod Path 1991;4:31)

● Associated with clustered microcalcifications (mimics cancer in mammograms)

Prognostic factors

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Case reports

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● In sentinel axillary nodes (Archives 2008;132:1439)

Treatment

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Clinical images

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Gross description (Macroscopy)

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● Multinodular, cuts with increased resistance

● Gritty but no chalky yellow-white foci or streaks

Gross images

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Micro description (Histopathology)

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● Low power diagnosis; increase in glandular elements plus stromal proliferation that distorts and compresses glands

● Maintains lobular architecture at low power with rounded and well defined nodules

● Centrally is more cellular with distorted and compressed ductules; peripherally has more dilated ductules

● Often microcalcifications, apocrine metaplasia

● Two cell layers are present, but myoepithelial cells may vary from being prominent to indistinct

● Also intralobular fibrosis, elastosis and apocrine metaplasia; florid changes are associated with pregnancy

● Rarely penetrates walls of veins or perineural spaces

● No necrosis, no pleomorphism

● Note: confused with carcinoma by new pathologists

Micro images

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Various images

Low power

Various images High power Late stage with increasing fibrosis

and decreasing acini

Core biopsy: microcalcifications with radial scar

Features of microglandular adenosis Myoid differentiation In sentinel nodes

AFIP Fig 52: ducts Fig 56-57: Small ducts with microcalcifications

dilated at periphery

Fig 58: Retention of myoepithelial-type Fig 59: Small bland ducts adjacent to nerve

cells but loss of ductal epithelium

Fig 53, 55: Intraductal papilloma Fig 54: Invagination into cystic duct

Fig 194, 195, 197: With LCIS Fig 70: Normal glands in upper right

Fig 198, 199: With LCIS and microinvasion (arrows)

HHF35 Smooth muscle actin CK5/6

Other images: Small ducts with microcalcifications #1; #2; Adenosis tumor #1; #2

Adenosis tumor

Virtual Slides

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ALH involving sclerosing adenosis

Other slides: Sclerosing adenosis with apocrine metaplasia

Videos

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Cytology description

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● Moderate to markedly cellular, with small to large groups of benign epithelial cells in acinar sheets and scattered individual epithelial cells

● Also small foci of dense hyalinized stroma (Acta Cytol 2001;45:353, Diagn Cytopathol 2008;36:496)

Cytology images

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Positive stains

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● Myoepithelial cells: smooth muscle actin, p63, calponin, HHF35, CK 5/6

● Basement membrane (surrounds tubules): laminin and type IV collagen

Negative stains

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Electron microscopy descriptions

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Electron microscopy images

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Molecular / cytogenetics description

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Molecular / cytogenetics images

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Differential Diagnosis

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● Invasive ductal carcinoma: not lobular at low power, cells have marked atypia, no myoepithelial cells

Additional references

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End of Breast-nonmalignant > Adenosis > Sclerosing adenosis

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