Image of the Week (19)

Core biopsy - Intracystic/Encysted Papillary Carcinoma

Intracystic papillary cacinoma - note monotonous (single cell type) population of epithelial cells and poorly formed cytoplasmic cores. Moderate apithelial atypia evident on mouse-over view

Intracystic papillary cacinoma - core biopsy - low power view

Detail from image above: A single cell population is present here but cytological atypia is not marked. 'Mouse over' shows absence of myoepithelial cells on CK5/6 immunostaining
Intracystic papillary cacinoma (detail - CK5/6 immunostain on mouse-over)


  1. It is emphasised that distinguishing benign from malignant papillary lesions can be difficult

  2. Careful scrutiny to determine whether there is a single cell or dual cell population in the lesion is key to making the correct diagnosis

  3. Immunostaining for myoepithelial markers can give considerable support for your diagnosis

  4. The absence of a peripheral myoepithelial layer around the lesion does not necesarily indicate that the lesion is invasive

Selected references:

1. Collins LC, Carlo VP, Hwang H, Barry TS, Gown AM, Schnitt SJ. Intracystic papillary carcinomas of the breast: a reevaluation using a panel of myoepithelial cell markers. Am J Surg Pathol. 2006 Aug ;30(8):1002-7.

2. Collins LC, Schnitt SJ. Papillary lesions of the breast: selected diagnostic and management issues.
Histopathology. 2008 ;52(1):20-29.

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