Breast - nonmalignant
Adenosis
Microglandular adenosis of breast

Author: Jaya Ruth Asirvatham, M.B.B.S., M.D. (see Authors page)
Editor: Julie M. Jorns, M.D.

Revised: 2 August 2017, last major update December 2014

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Microglandular adenosis [title] breast

Cite this page: Microglandular adenosis of breast. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/breastmicroglandularadenosis.html. Accessed December 14th, 2017.
Definition / general
  • Rare lesion of haphazardly infiltrating, small, uniform, rounded, open glands with eosinophilic secretions
  • Mimics invasive carcinoma due to irregularly distributed glands in fibrous or adipose tissue, lined by single layer of cells
Terminology
  • Also called microglandular hyperplasia
Clinical features
Radiology description
  • Increased density or calcifications
Case reports
Treatment
Gross description
  • Palpable mass or small localized lesion
  • Infiltrative and ill defined
  • Usually 3 - 4 cm
Microscopic (histologic) description
  • 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, prominent nucleoli, reduced intraluminal secretions, occasional mitotic figures
    • Intact basement membrane
Microscopic (histologic) images

Images hosted on PathOut server:

Multilayered epithelium with granular cytoplasm (AFIP)

Small round infiltrative glands (AFIP)

H&E and reticulin stain, courtesy of Dr. Mark R. Wick



Images hosted on other servers:

Haphazard glands apparently infiltrating stroma

Ducts lined by single cells with secretory material

Smooth round glands


Small uniform glands with open lumina

With ALH

With invasive and intraductal carcinoma

Fig 2: Atypical microglandular adenosis

Virtual slides

Images hosted on other servers:

Microglandular adenosis

With invasive ductal carcinoma

Cytology description
  • 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)
Positive stains
Negative stains
Electron microscopy description
Molecular / cytogenetics description
  • Clonal in some cases
Differential diagnosis