What are the two forms of papilloma?

• A. Intracystic and intraductal
• B. Invasive and noninvasive
• C. Benign and malignant
• D. Polarized and non-polarized

Answer: (A)

Papillomas are papillary proliferations that arise in two different breast environments: within a duct or into a cyst. The intraductal form develops inside a duct (often near the nipple) and can cause unilateral nipple discharge. On ultrasound, it tends to appear as a small, solid, often pedunculated lesion inside a dilated duct, and Doppler may show a vascular stalk feeding the lesion. The intracystic form grows into the cavity of a breast cyst, presenting as a mural papillary projection from the cyst wall into the cyst lumen; ultrasound shows a solid nodule projecting within the cyst.

These two settings—intracystic and intraductal—are the recognized forms of papilloma, which is why the correct answer is intracystic and intraductal. The other pairings describe benign vs malignant, invasive vs noninvasive, or unrelated terms that don’t define the two anatomical forms of papilloma.