ORIGINAL ARTICLE

The role of immunohistochemistry for smooth-muscle actin, p63, CD10 and cytokeratin 14 in the differential diagnosis of papillary lesions of the breast

G M K Tse¹, P-H Tan², P C W Lui¹, C B Gilks³, C S P Poon⁴, T K F Ma⁴, B K B Law⁵ and W W M Lam⁶

¹ Department of Anatomical and Cellular Pathology, Prince of Wales Hospital, Chinese University of Hong Kong, Hong Kong SAR, China
² Department of Pathology, Singapore General Hospital, Singapore
³ Department of Pathology, Vancouver General Hospital, Vancouver, British Columbia, Canada
⁴ Department of Pathology, North District Hospital, Hong Kong SAR, China
⁵ Breast Center, Union Hospital, Hong Kong SAR, China
⁶ Department of Diagnostic Radiology and Organ Imaging, Chinese University of Hong Kong, Hong Kong, SAR, China

Correspondence to:
Correspondence to:
Dr G M K Tse
Department of Anatomical and Cellular Pathology, Prince of Wales Hospital, University of Hong Kong, Ngan Shing Street, Shatin NT, Hong Kong SAR, China; garytse{at}cuhk.edu.hk

Background: Histological differentiation of mammary papillary lesions can be difficult. The evaluation of myoepithelial cells can be helpful, with benign papilloma showing a continuous myoepithelial cell layer, which becomes attenuated or absent in malignant papillary lesions.

Methods: A large series of 100 papillomas (28 papillomas with florid epithelial hyperplasia) and 68 papillary carcinomas (9 invasive, 44 in situ, and 15 ductal carcinomas in situ (DCIS) involving papillomas) of the breast were stained for myoepithelial cells by immunohistochemistry using antibodies to smooth-muscle actin (SMA), p63, CD10 and cytokeratin (CK) 14.

Results: In the papillomas, using these four antibodies, myoepithelial cells were positive in 88%, 99%, 91% and 95% of cases, respectively, with SMA showing marked stromal component cell staining and CD10 showing epithelial and stromal staining. CK14 also showed epithelial staining in 71% of papillomas and 96% of papillomas with florid epithelial hyperplasia. In the papillary carcinomas, 36 (53%) cases showed staining of myoepithelial cells that were scattered, discontinuous and diminished in number and the remaining 32 (47%) cases did not show myoepithelial cells. Invasive papillary carcinoma has the lowest proportion (33%) with myoepithelial cells, and DCIS involving papillomas had the highest proportion (87%).

Conclusions: p63 had the highest sensitivity and did not cross-react with stromal cells and only rarely with epithelial cells. CK14 has the added ability to distinguish between florid epithelial hyperplasia involving papilloma and DCIS involving papillomas. CK14 and p63 may be used as an adjunct in assessing difficult papillary lesions of the breast.

Abbreviations: DCIS, ductal carcinomas in situ; SMA, smooth-muscle actin

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This article has been cited by other articles:

• Tse, G M, Tan, P H, Moriya, T (2009). The role of immunohistochemistry in the differential diagnosis of papillary lesions of the breast. J. Clin. Pathol. 62: 407-413 [Abstract] [Full Text]  
• Tan, P H, Tse, G M K, Bay, B H (2008). Mucinous breast lesions: diagnostic challenges. J. Clin. Pathol. 61: 11-19 [Abstract] [Full Text]