Mass-forming papillary carcinomas in situ - Intracystic papillary carcinoma


Intracystic papillary carcinoma of the breast has provoked controversy as to whether it is truly in situ or in fact invasive disease. The issue revolves around the absence of a discernible myoepithelial layer at the interface with the adjacent stroma. Most practitioners now believe that even in the absence of invasion it is an invasive lesion but with a low potential for metastatic spread and therefore should in the first instance be managed as in situ disease. If an invasive focus is found in a subsequent excision then appropriate further treatment should be considered.

Intracystic papillary carcinoma

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Intracystic papillary carcinoma - macro Intracystic papillary carcinoma - low power micro
Macro of intracystic papillary carcinoma (left) with low power view (right)
Intracystic papillary carcinoma - detail
Detail of intracystic papillary carcinoma. This tumour is low grade. The tall columnar epithelial cells are typical of the lesion. Fibrovascular cores in this example are relatively well developed. Myoepithelial cells are absent.

Intracystic papillary carcinoma - core biopsy H and E Intracystic papillary carcinoma - CK14 immunostain
Core biopsy (H&E) of intracystic papillary carcinoma (left) with negative CK14 immunostain (right)


Mass-forming papillary carcinomas in situ - solid papillary carcinoma



Solid papillary carcinomas of the breast are uncommon and cause considerable diagnostic difficulty, particularly on core biopsy. The key to diagnosis is the recognition of a vascular network running through the tumour - a feature that is not seen in invasive carcinomas. The tumour may be circumscribed or, less commonly, more dispersed and nodular. The presence of invasive carcinoma arising from these lesions is much more common than in intracystic papillary carcinomas.

Solid papillary carcinoma - core biopsy H and E solid papillary carcinoma - detail
Core biopsy (H&E) of solid papillary carcinoma (low power left) with detail (right). Arrows point to the vascular network
Solid papillary carcinoma - core biopsy CK14 immunostain Solid papillary carcinoma - P63 immunostain
Core biopsy of the same solid papillary carcinoma with an ambiguous CK14 immunostain (left) and a completely negative P63 immunostain on the right. The blue arrows show the interface with the adjacent stroma where myoepithelial cells are absent as is usual for the majority of mass-forming papillary carcinomas.

Solid papillary carcinoma - excision
Low power view of excised solid papillary carcinoma. This has a more dispersed multi-nodular architecture.
Solid papillary carcinoma - core biopsy CK14 immunostain Solid papillary carcinoma - P63 immunostain
Detail from above tumour showing small foci of invasion (arrows). The CK14 immunostain on the right should be interpreted with caution; because these lesions have no detectable myoepithelium the absence of myoepithelium per se should not be regarded as proof of invasion. Invasion has to be determined by H&E interpretation. The immunostain has clearly worked in this example with a strongly staining normal duct on the right hand side of the image.

Papillary pattern DCIS


This is uncommon. I include an example for completeness.
Papillary DCIS Papillary DCIS
Papillary pattern DCIS of intermediate grade

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