Intraductal papillary carcinoma

INTRADUCTAL PAPILLARY CARCINOMA

• These tumors are either solitary or multiple. solitary lesions are central and multiple lesions are distributed peripherally
• Accounts for less than 2% of breast malignancies
• Age group – common in elderly ( more than 30 years)
• Papillary lesions are associated with abnormalities in 16q. In papillary carcinoma loss of heterozygosity on chromosome 16p13 is noted

Gross –

• These are usually well circumscribed
• Bleeding into the tumor may produce hemorrhagic cystic lesion and may be tan or gray in appearance

Microscopy

• Lesion contains papillae with delicate fibrovascular cores and are lined by tumor cells
• Myoepithelial cell layer will be absent in 90% of these papillary processes
• They can also have solid and cribriform patterns
• Myoepithelial cell layer is absent in papillary process and also for the distended duct in which the lesion is present
• Tumor cells may be small rounded to spindle cells or columnar cells or apocrine cells
• Distinction between papilloma and intraductal papillary carcinoma is difficult and in such cases immunohistochemistry for myoepithelial cells (p63, CD10, Calponin) may be helpful.
• Prognosis is good in the absence of invasive component.