Intraductal papilloma is a benign tumor found within breast ducts. The abnormal proliferation of ductal epithelial cells causes the growth. A solitary intraductal papilloma is usually found centrally posterior to the nipple affecting the central duct. Multiple intraductal papillomas are located peripherally, found in any breast quadrant affecting the peripheral ducts. Women of all ages can develop intraductal papillomas. Breast tumor risk factors include contraceptive use, hormone replacement therapy, lifetime estrogen exposure, and family history.
Patients with symptoms often present with spontaneous bloody or clear nipple discharge. An intraductal papilloma may be occasionally palpable. However, most patients with an intraductal papilloma are asymptomatic. Small intraductal papillomas often will show no signs or symptoms. 
Working up an intraductal papilloma is imperative due to the possibility of harboring occult carcinoma.  It is classified as a high-risk precursor lesion due to its association with atypia, ductal carcinoma in situ (DCIS), and carcinoma.  Surgical excision with complete tumor removal is the recommended treatment. 
Intraductal papilloma is classified as a high-risk precursor lesion. This classification is due to its association with atypia, DCIS, and carcinoma. Intraductal papilloma is a benign breast tumor.  Breast tumor predisposing risk factors include contraceptive use, hormone replacement therapy, lifetime estrogen exposure, and family history. 
Intraductal papilloma diagnosed on core biopsy can have surgical excisional upgrade to atypical ductal hyperplasia, DCIS, and carcinoma.  Breast lesions diagnosed as benign papillomas on core needle biopsy had a 6.3% risk of being malignant.  Central papillomas are usually solitary and large in size. Peripheral papillomas, in contrast, are usually smaller and may be multiple in number.  Intraductal papilloma can be found in both large ducts of the subareolar region and the terminal duct lobular unit (TDLU) more peripherally. Intraductal papilloma is histologically characterized by a fibrovascular core covered with both epithelial and myoepithelial cells. A variety of changes can accompany intraductal papilloma which includes sclerosis, epithelial or myoepithelial hyperplasia, atypical proliferation, and squamous or apocrine metaplasia. 
Intraductal papillomas when solitary may present as bloody or clear nipple discharge. They are usually centrally located behind the nipple and most commonly seen in perimenopausal patients. However it may also be seen incidentally with ultrasound in younger asymptomatic patients. Intraductal papillomas when multiple typically arise from the TDLU. They are less frequently presented with nipple discharge, and more often as a palpable mass. 
Intraductal papilloma can be mammographically occult. When seen mammographically it may present as a round or oval mass with a well-circumscribed or indistinct margin. It may be associated with microcalcifications. Under ultrasound, the mass is commonly found near the nipple. The tumor will be in a dilated duct and will often show flow on color or power Doppler. On galactography, intraductal papilloma appears as an intraluminal filling defect with ductal dilation leading up to the mass with an abrupt ductal cutoff. MRI findings include an enhancing round or ovoid intraductal mass with likely either washout or plateau kinetics. 
Tissue sampling in addition to imaging is necessary for the diagnosis of intraductal papilloma. Radiologic findings and pathologic tissue findings need to be concordant for accurate diagnosis.  There are different types of biopsy methods which include core needle, vacuum assisted, and open tissue biopsy. Core needle and vacuum assisted biopsy are preferred over fine needle aspiration due to more tissue sample obtained for pathologic analysis. Fine needle aspiration uses a thinner needle creating the chance for insufficient tissue sampling.  Open tissue biopsy is not preferred as it is a surgical approach. It is more invasive and may lead to chronic pain and increased patient anxiety and depression. 
Both benign and malignant lesions can mimic intraductal papilloma. Inspissated material or debris within a dilated duct can mimic papilloma. Similarly, fat necrosis with cystic and solid areas can mimic an intracystic papillary lesion. The absence of intralesional color flow on ultrasound favors benignity. Phyllodes tumor is a benign but high risk lesion that can similarly look like papilloma. Malignant nonpapillary tumors such as medullary carcinoma can present with central necrosis or ductal extension mimicing a papillary carcinoma. Ultimately, the diagnosis of intraductal papilloma will require tissue sampling for definitive diagnosis. 
Prognosis is overall excellent with intraductal papilloma. In one particular study, 88.9% of the intraductal papillomas were found to be without atypia while 9.2% showed atypia. The upgrade rate on pathology was low found to be 7.3%: 1.3% for invasive cancer, 2.7% for DCIS, and 3.3% for atypical ductal hyperplasia.  Surgical excision with complete tumor removal is the recommended treatment.  Local recurrence after surgical excision is low, as low as 2.4% in one study. 
No significant complications are seen with intraductal papilloma. Complications when present are seen after biopsy or after surgical excision. Postprocedural complications may include bleeding, infection, pain, fat necrosis, and possible cosmetic deformity to the breast. 
Breast tumor risk factors both benign and maligant include contraceptive use, hormone replacement therapy, lifetime estrogen exposure, and family history.  Women should be encouraged to undergo annual screening mammograms. The American College of Radiology and Society of Breast Imaging recommends annual screening mammogram beginning at age 40 for women of average risk.
Healthcare professionals should educate patients about breast cancer and other breast lesions. The nurse is in a prime position to teach the patient about breast exams, which may help detect any breast abnormalities early. In addition, the nurse should encourage women to undergo screening mammograms. At the same time, the patient should be encouraged to follow up with regular breast exams by the primary care provider.
For women who undergo excision of the intraductal papilloma, the outcomes are excellent. All women should be encouraged to undergo screening mammograms. The American College of Radiology and Society of Breast Imaging recommends annual screening mammogram beginning at age 40 for women of average risk.
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