Intraductal papilloma typically presents in middle-aged women with nipple discharge, characterised by a solitary, smooth-walled intraductal nodule with a vascular feeding stalk, predominantly located in the subareolar region.
Description
Intraductal papilloma is a benign breast tumor, originating from the epithelial and myoepithelial cells lining the milk ducts. It is considered the most common cause of pathological nipple discharge in non-lactating women. These tumors are typically small, often less than 2 cm in size, and can occur solitarily or as multiple lesions in a condition known as papillomatosis.
Pathogenesis
The exact cause of intraductal papilloma is unclear, but it is believed to result from an abnormal proliferation of the epithelial and myoepithelial cells lining the milk ducts. Hormonal factors may play a role, as the condition most commonly occurs in women of reproductive age. There is also an association with minor duct ectasia and fibrocystic changes.
Subtypes
- Central Papilloma – Most common, typically solitary and occurring in the central or subareolar area
- Peripheral Papilloma – More likely to be multiple. Often found in peripheral ducts and associated with an increased risk of carcinoma.
Epidemiology, Risk Factors & Associations
- Greatest risk factor: Female gender, especially in the 35-55 age group.
- Association with fibrocystic breast changes (30-40% cases).
- Slight increase in risk of breast cancer, especially with multiple papillomas.
Clinical Features
There are no pathognomonic signs or syndromes associated with intraductal papilloma.
- Central papillomas: Patients typically present with serous or bloody nipple discharge. Palpable mass may be present in the subareolar area.
- Papillary papillomas: Less likely to present with nipple discharge.
Complications
- Risk of malignant transformation: Low (<2%), usually to ductal carcinoma in situ (DCIS) or invasive ductal carcinoma.
- If malignant, potential metastatic sites include axillary lymph nodes, lung, bone, and brain, though rare.
Pathological Features
Histopathology
- Macroscopic: Small, wart-like growth within the ducts.
- Microscopic: Fibrovascular cores lined by a dual layer of epithelial and myoepithelial cells.
Serology
- Not applicable.
Biochemistry
- Not relevant.
Radiological Features
General Features
- Characteristically demonstrates a non-calcified mass in a dilated duct.
- Central papillomas are located more anteriorly (close to nipple)
- Peripheral papillomas are located more posteriorly
- Solitary lesions typically appear in the subareolar area, while multiple lesions are found in peripheral ducts.
- Calcifications are rare.
- Galactography Sign – Ductal filling defects.
- Often associated with minor duct ectasia.
Mammogram
- Can show a circumscribed or obscured mass.
- Microcalcifications are rare but may be present in papillomatosis.
- Dilated ducts may be visible in some cases.
US
- B-mode: Shows a smooth-walled nodule in a dilated duct.
- Colour: Shows vascular flow through a feeding stalk.
Grading and Staging
No specific grading or staging system for intraductal papilloma.
Diagnosis
Diagnosis is confirmed through histopathological examination of the excised lesion. Imaging modalities like ultrasound and MRI can suggest the diagnosis, but biopsy is definitive.
Differential Diagnosis
- Fibroadenoma: Typically solid, well-circumscribed mass, common in younger women.
- Ductal Carcinoma in Situ (DCIS): May present with nipple discharge, mammographic microcalcifications.
- Breast Cancer: Irregular mass, spiculated margins, more common in older women.
Management
Management typically involves surgical excision. Referral to a breast surgeon or surgical oncologist is recommended. Follow-up imaging is advised to monitor for recurrence or development of breast cancer.