What is a sclerosing intraductal papilloma of the breast?

What is a Sclerosing Intraductal Papilloma of the Breast?

A sclerosing intraductal papilloma is a benign breast lesion characterized by a papillary growth within the milk ducts that has undergone fibrotic changes (sclerosis), representing a variant of the more common intraductal papilloma. 1, 2

Pathologic Features

Sclerosing intraductal papillomas develop when benign intraductal papillary lesions undergo progressive fibrosis and sclerotic changes over time. 2 This sclerotic transformation can make these lesions diagnostically challenging because:

• The sclerosis may obscure the underlying papillary architecture 2
• They can demonstrate pseudoinfiltration patterns that mimic malignancy 2
• Cytologic atypia may be present, raising concern for carcinoma 2
• Despite these worrying features, immunohistochemical staining demonstrates an intact myoepithelial layer and basement membrane, confirming their benign nature 2

Clinical Presentation

Sclerosing intraductal papillomas typically present in one of two ways:

• As a palpable breast mass that may clinically mimic carcinoma 2
• With pathologic nipple discharge (spontaneous, unilateral, single-duct, serous or bloody) 3, 4
• Less commonly, they may present as a pigmented nodule on or near the nipple 5

The lesions are usually solitary and occupy medium- to large-sized breast ducts, though multiple lesions can occur 2. They can affect women of all ages, though the majority of patients are 60 years or older 2.

Diagnostic Approach

When a sclerosing intraductal papilloma is suspected, mammography should be the first-line imaging modality for patients ≥40 years. 3, 4 However, imaging findings are often nonspecific:

• Mammography may show asymmetrically dilated ducts, a circumscribed subareolar mass, or grouped microcalcifications 3
• Ultrasound is more sensitive than mammography and should be performed in all patients with pathologic nipple discharge 4
• Imaging may be completely normal despite the presence of a papilloma 5

Core needle biopsy is essential for definitive diagnosis, as imaging alone cannot reliably distinguish benign from malignant lesions. 3

Management and Malignancy Risk

Complete surgical excision is the standard management for intraductal papillomas (including sclerosing variants) diagnosed at biopsy, as there is a 3-14% risk of malignancy upgrade at final pathology. 4 This recommendation is based on:

• The inability to completely exclude malignancy on core biopsy alone 4
• The potential for sampling error with core needle biopsy 4
• The need for complete histopathologic examination to rule out associated atypia or carcinoma 2

Surgical excision provides both definitive diagnosis and treatment, with excellent outcomes and no increased risk of subsequent malignancy for solitary papillomas. 4, 6 After local excision, patients with solitary sclerosing papillomas have uneventful follow-up and insufficient increase in malignancy risk to justify routine surveillance 2, 6.

Important Clinical Pitfalls

The sclerotic changes in these lesions can create diagnostic uncertainty and mimic invasive carcinoma on both imaging and histology. 2 Key points to avoid misdiagnosis:

• Do not rely on imaging characteristics alone—tissue diagnosis is mandatory 3
• Ensure adequate tissue sampling, as the sclerotic areas may obscure the papillary architecture 2
• Immunohistochemical staining for myoepithelial markers should be performed when there is diagnostic uncertainty 2
• Any discordance between imaging and pathology findings requires surgical excision 4

Patients with multiple papillomas (papillomatosis) have an increased cancer risk and require different management than those with solitary lesions, including annual surveillance with digital mammography. 6