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Breast-nonmalignant

Microglandular adenosis of breast

 

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

Revised: 3 February 2013, last major update - March 2010

Copyright: (c) 2002-2013, PathologyOutlines.com, Inc.

 

Definition

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● Rare lesion of haphazardly infiltrating, small, uniform, rounded, open glands with eosinophilic secretions

● Irregularly distributed in fibrous or adipose tissue, lined by single layer of cells

 

Terminology

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● Also called microglandular hyperplasia

 

Epidemiology

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● Rare

 

Sites

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Etiology

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Clinical features

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● Benign, although associated with carcinoma (Am J Surg Pathol 1986;10:237)

● May evolve into carcinoma (Int J Surg Pathol 2000;8:303, Am J Surg Pathol 2009;33:496), often adenoid cystic carcinoma (Am J Surg Pathol 2003;27:1052)

● Some cases are precursors of basal-like carcinoma (Histopathology 2009;55:732)

 

Prognostic factors

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Case reports

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● Invasive carcinoma arising within microglandular adenosis (Archives 2003;127:77)

 

Treatment

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● Complete excision to rule out invasion (Am J Surg Pathol 2008;32:544) and close followup, particularly if atypical features (Am J Surg Pathol 1983;7:137)

● May recur if incompletely excised

 

Clinical images

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Gross description (Macroscopy)

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● Palpable mass or small localized lesion

● Infiltrative and ill defined

● Usually 3-4 cm

 

Gross images

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Micro description (Histopathology)

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● Haphazardly infiltrating collection of small uniform, rounded, open glands with eosinophilic secretions, irregularly distributed in fibrous or adipose tissue

● Glands lined by single layer of cuboidal/flat cells with vacuolated/granular cytoplasm and bland nuclei

● No apocrine snouts, no nucleoli, no/variable myoepithelial layer, but thick basement membrane

 

Atypical microglandular adenosis:

● Pleomorphic glands and microacini

● Budding glandular units and luminal bridging, mild cytologic atypia, reduced intraluminal secretions, occasional mitotic figures

 

Micro images

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Haphazard glands apparently                         Ducts lined by single cells and containing

infiltrating stroma                                              secretory material

 

 

  

Small uniform glands with open lumina

 

 

en12.jpg (54219 bytes)                                en12.jpg (54219 bytes)

Small round, regular glands,           Smooth round glands with bland nuclei

some dilated, within adipose          and focally vacuolated cytoplasm

 

 

                                                                   

Fig 1: microglandular adenosis                                      Microglandular adenosis with ALH

Fig 2: atypical microglandular adenosis

 

 

               

Case report with associated invasive and intraductal carcinoma

 

 

                                                             

AFIP Fig 69: multilayering of epithelium        AFIP Fig 67-68: small round infiltrative glands

with granular cytoplasm

 

Drawings

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Virtual Slides

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With microcalcifications                  With invasive ductal carcinoma

 

Videos

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Cytology description

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 Sparse cellularity, monotonous population of medium sized cells with vacuolated clear cytoplasm, round and uniform nuclei, small nucleoli

 Also clear cells that are solitary or clustered with spindly fibroblasts (Diagn Cytopathol 1993;9:72)

 

Cytology images

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Positive stains

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● CAM 5.2, AE1, S100 (Archives 2007;131:1397), p63 (secretory epithelium, Histopathology 2005;47:611)

CK 8/18 and EGFR (Am J Surg Pathol 2008;32:544)

● PAS+ diastase resistant secretions

● Variable smooth muscle actin, vimentin, type IV collagen and laminin (around glands)

 

Negative stains

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● ER, PR, HER2 (triple negative)

● Actin, calponin, p63 (myoepithelial markers)

● EMA, GCDFP-15,

● p53, low Ki-67

 

Electron microscopy descriptions

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● Thick basement membrane around epithelium; electron-lucent cytoplasm, sparse organelles (Am J Surg Pathol 1983;7:731)

 

Electron microscopy images

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Molecular / cytogenetics description

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● Clonal at least in some cases

 

Molecular / cytogenetics images

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Differential Diagnosis

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Apocrine adenosis: larger glands lined by luminal tall columnar cells with apocrine features and surrounded by flat myoepithelial cells

Invasive ductal carcinoma with a microglandular adenosis pattern (Ann Diagn Pathol 2004;8:39)

Tubular carcinoma: stellate growth pattern, desmoplastic stroma, glands vary in size and shape with angulated “tear-drop” appearance; lined by cells with prominent apical snouts and without a surrounding basement membrane; EMA+, S100- (Archives 2007;131:1397)

 

Additional references

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Stanford University, article by Drs. Joshi and Ahmad (May 2011)

 

End of Breast-nonmalignant > Adenosis > Microglandular adenosis

 

 

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