Papillary lesions are growths that develop within the breast ducts, ranging from benign (non-cancerous) to malignant (cancerous). The term “atypical” signifies a particular subset requiring careful attention due to its association with an elevated future risk of breast cancer. This understanding guides diagnostic and management strategies.
What Are Atypical Papillary Lesions?
A papillary lesion is a benign, finger-like projection that grows inside the milk ducts of the breast. The term “atypical” indicates that cells within the papilloma display abnormal features, though not yet full characteristics of cancer.
While most papillary lesions are benign, atypia means an increased future risk for breast cancer. This elevated risk makes atypical papillary lesions a significant finding, warranting close monitoring. Papillomas with atypical cells are considered “high-risk precursor lesions” because they can sometimes harbor or progress to conditions like ductal carcinoma in situ (DCIS) or invasive carcinoma.
How Atypical Papillary Lesions Are Identified
Atypical papillary lesions are often discovered during routine breast imaging, such as a mammogram, ultrasound, or MRI. On imaging, they can appear as a mass, an intracystic lesion, microcalcifications, or a dilated duct. Specific imaging features may suggest potential malignancy.
Imaging alone cannot definitively distinguish between benign, atypical, or malignant papillary lesions. A definitive diagnosis requires a tissue biopsy for pathological examination, typically performed using core needle or vacuum-assisted biopsy. Due to potential sampling error, a core needle biopsy diagnosis of an atypical papilloma often leads to surgical excision to ensure a complete and accurate pathological assessment.
Classifying Atypical Papillary Lesions
Classification of atypical papillary lesions is based on specific abnormal cell changes observed by a pathologist. The World Health Organization (WHO) classification uses more specific terminology than “atypical papilloma.” One common classification is “intraductal papilloma with Atypical Ductal Hyperplasia (ADH),” where atypical epithelial proliferation is present but limited in extent.
A more concerning classification is “intraductal papilloma with Ductal Carcinoma In Situ (DCIS),” where atypical proliferation is more extensive or if intermediate to high-grade atypia is present. The distinction between ADH and DCIS within a papilloma is significant, indicating different breast cancer risks and influencing management decisions.
Treatment and Monitoring
Standard management for atypical papillary lesions typically involves surgical excision. This is often recommended even if initial biopsy showed only atypia, as more serious lesions like DCIS or invasive carcinoma might be present upon complete removal. Studies show a significant percentage of atypical intraductal papillomas diagnosed by core needle biopsy are “upgraded” to DCIS or invasive carcinoma after surgical excision.
Following surgical removal, continued follow-up care is generally recommended due to the elevated lifetime risk of breast cancer. Surveillance may include regular mammograms and clinical breast exams. The goal is to monitor for new breast changes or the development of further atypical lesions or cancer.