Intraductal papillomas can be seen in women of any age, mostly in women aged 40 to 45 years.
Seventy-five percent of lesions occur in the enlarged portion of the large duct near the nipple. The tumor is usually very small, and a papillary nodule with a tip of a rice grain or a green bean is visible to the naked eye in the lumen of the duct, rich in thin-walled blood vessels and bleeding easily. The clinical features are that the papillae sometimes overflow with bloody fluid without pain, but the masses are not easily palpable. Papillomas are often not easily palpable during clinical examination because they are small and soft, and sometimes small nodules can be palpated under the areola without skin adhesions. When the areola area is gently pressed or the nipple is squeezed, there is bloody drainage that can help locate it. If the lesion is extensive in small and medium-sized ducts, located at the margins of the breast, often multiple, it is called intraductal papillomatosis and is considered a precancerous lesion. Intraductal papillomas are generally considered to be benign, but in 6-8% of cases there is a possibility of malignancy, so early surgical excision should be sought. It is mainly detected by cytological examination, ductography, and ductoscopy. The location and extent of the ductal lesion should be understood before surgery, and there is a tendency for recurrence in multiple cases. Papilloma of the infundibulum is easier to locate if a mass can be palpated. If the nodule is not palpable, the duct and its surrounding breast tissue can be wedge-shaped excised by pressing clockwise along the areola to clarify the opening of the bleeding duct, then using a probe to insert the duct and intraoperative contrast with melanoma, and making a radial incision in the direction of the lesion’s visualization. Small duct papillomas are often multiple, often intraductal papillomatosis, and have a tendency to become malignant. In older patients, simple mastectomy should be considered if necessary. The excised tumor is routinely examined pathologically, and if malignant, treated surgically as appropriate for breast cancer. Clinically, intraductal papilloma needs to be differentiated from intraductal papillary carcinoma and ductal dilatation syndrome. 1. Intraductal papilloma and intraductal papillary carcinoma: Both can be seen as spontaneous, painless bloody nipple discharge; both can be found as an areolar lump, and when pressing the lump, bloody fluid can be spilled from the opening of the milk duct. The differential diagnosis is difficult because the clinical presentation and morphologic features of the two are very similar. It is generally believed that the overflow from intraductal papilloma can be bloody, plasma blood or plasma fluid, while the overflow from papillary carcinoma is more common to be bloody and is mostly unilateral with a single orifice. In papillary tumors, the masses are mostly located in the areola area, with soft texture, and the masses are usually no larger than 1 cm, and the lymph nodes in the ipsilateral axilla are not enlarged; whereas in papillary carcinoma, the masses are mostly located outside the areola area, with hard texture, unsmooth surface, poor mobility, and easy adhesion to the skin, and the masses are usually larger than 1 cm, and the enlarged lymph nodes in the ipsilateral axilla are visible. The following features can be found on mammography or ductoscopy: abrupt interruption of the duct, smooth cupping of the broken end, marked dilatation of the proximal duct, sometimes round or ovoid filling defect or neoplastic occupancy, soft and neat duct, mostly intraductal papilloma; if the broken end is not neat, the proximal duct is mildly dilated, distorted, disorganized, filling defect or complete obstruction, the duct loses its natural If the ducts lose their natural softness and become stiff, then it is most likely to be intraductal carcinoma. The cytological examination of overflow smear can find cancer cells in papillary carcinoma. The final diagnosis should be based on pathological diagnosis, and paraffin section should be done to avoid false negative or false positive results due to the limitation of frozen section. 2. Intraductal papilloma and ductal dilatation syndrome: The main symptom of both ductal papilloma and ductal dilatation syndrome is nipple discharge, but ductal dilatation syndrome is often accompanied by congenital nipple depression, and the discharge is mostly bilateral porous, and the nature can be watery, milk-like, plasma-like, pus-blood or blood-like. However, the lumps in the latter are often larger than those in the former, and the lumps are irregular in shape, hard and tough, and may adhere to the skin, often with painful redness and swelling, and later ulceration and pus flow. Ductal dilatation syndrome is also seen with enlarged and painful axillary lymph nodes on the affected side. The following features can be found on mammography or ductoscopy: abrupt interruption of the ducts, regular filling defects or neoplastic occupancy, mostly papilloma; if the larger ducts are significantly dilated, with uneven duct thickness and loss of the normal regular dendritic shape, it is mostly duct dilatation syndrome. If necessary, needle aspiration cytology or biopsy of the mass is feasible.