Breast papilloma: Clinical sciences

Breast papillomas result from the abnormal growth of epithelial cells into the ductal lumen. Papillomas can be solitary and centrally located, arising in the main lactiferous ducts, or they can be multiple and peripheral, involving the terminal ductal lobular unit. Papillomas are generally benign but can be associated with other high-risk lesions, and rarely, malignant pathologies.

When assessing a patient with a chief concern suggestive of breast papilloma, first obtain a focused history and physical exam. Patients might report spontaneous unilateral nipple discharge, ranging in consistency from clear to bloody. They may have noticed a breast lump or had an abnormal screening mammogram.

On physical exam, you might palpate a breast mass, but this is less common. An important thing to do is to attempt and elicit nipple discharge. Apply gentle pressure around the areola in a clockwise fashion, and if nipple discharge occurs note the location of the duct and the exact site of your applied pressure when it was expressed. Also take note if the discharge appears to be serous to serosanguinous, or frankly bloody.

Here’s a clinical pearl! If the nipple discharge does not appear to be bloody, it can be tested with a Guaiac test kit to assess for the presence of any occult blood.

Now, if you see these findings in history and physical, you should suspect breast papilloma and order some imaging. The first step is to obtain a breast ultrasound and a diagnostic mammogram. On ultrasound, you might see a solid nodule or mass within a dilated breast duct, as well as its associated fibrovascular pedicle. On a diagnostic mammogram, findings are oftentimes normal or unremarkable. However, a round or mass may be seen, and occasionally even a cluster of central or peripheral microcalcifications. If you see any of these findings, you’ll want to proceed to a core needle biopsy for further investigation.

Here’s a clinical pearl! If your patient with unilateral spontaneous nipple discharge has negative ultrasound and mammogram findings, it does not mean that you should discontinue your workup! Several advanced imaging options can be used in your clinical investigation. The first step is to obtain a breast MRI. If this is negative, two additional invasive imaging studies are available: galactography and ductoscopy. Galactography utilizes the injection of contrast material into a cannulated breast duct combined with mammography. A filling defect seen on imaging confirms the diagnosis of an intraductal papilloma and helps to identify its location. When it comes to ductoscopy, this utilizes a very small camera that can visually explore breast ducts. This can be therapeutic as well as diagnostic when combined with surgery. Dye, such as methylene blue, can be injected into the duct after locating a papillary lesion with ductoscopy, and then the same duct can be identified and removed through a small periareolar incision.

Okay, once imaging is complete, and you still think the patient might have breast papilloma, the next step is to confirm the diagnosis by obtaining a tissue sample using a core needle biopsy.

First, let’s see what it would look like on core needle biopsy. So, papillomas appear as intraductal proliferations of branching fibrovascular stalks that are lined with orderly layers of ductal epithelial cells and myoepithelial cells.

Less frequently, papillomas can also present with focal necrosis, so do not misinterpret the presence of necrosis as a sign of atypia or malignancy! In fact, the biopsy will also reveal the absence of any atypical or malignant cells. If this is the case, you are dealing with an intraductal papilloma or papillomatosis.

The difference is that intraductal papilloma means that there is a solitary central papilloma, while in papillomatosis there are multiple peripheral papillomas. More specifically, patients with papillomatosis have five or more papillomas within a local segment of breast tissue. Additionally, patients with papillomatosis might have a higher chance of bilateral lesions, so when this is the case always double-check to make sure that both breasts were examined and imaged.