Image of the Week (2009-1)

Excision biopsy - Microglandular adenosis

Microglandular adenosis - excision - the lesion occupies the bulk of the central area of this photograph and is surrounded by benign ductal and acinar structures. Detail of central area seen in mouse-over view

Microglandular adenosis - excision - low power view

Detail from image above: The 'microglandular adenosis' acini are on the left and are composed of a single layer of cuboidal epithelial cells with pink luminal secretions. Please note the contrast with the adjacent two layered sclerosed lobule (A). 'Mouse over' shows further detail. A focus of apocrine metaplasia is present on the left (B)
Microglandular adenosis - excision


  1. Microglandular adenosis is a very rare benign condition that can be easily mistaken for low grade carcinoma, particularly as a bounding myoepithelial layer is absent

  2. Atypical variants are recognised

  3. The cells show positive immuno staining with S100, CK 8/18 & EGFR and negative staining for ER, PGR & Her-2

  4. Immuno stains for Collagen IV or laminin are usually positive indicating an intact bounding basement membrane

  5. There is an association with atypical proliferations and malignancy in up to 50% of cases

See also Sclerosing Lesions.


I am extremely grateful to Dr Mark Ashton, Consultant Pathologist, Raigmore Hospital, Inverness, who kindly loaned me the section from which these photomicrographs have been taken.

Selected reference:

1. Kempson RL and Rouse RV in Stanford University Definitions.

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