BREAST CYTOPATHOLOGY

Intraductal Papilloma/Papillomatosis 67
Pitfalls and Differential Diagnosis
• The distinction between fibroadenoma and phyllodes
tumor in an aspirate is based on the cellularity of the
stromal elements seen in phyllodes tumors and is not always
possible to visually appreciate. The size of the lesion is not
a valid distinguishing feature.
• Diagnosis of low-grade or malignant phyllodes tumor is
extremely difficult. These cases should be carefully evaluated
for the presence of abnormal mitoses and pleomorphism.
Other entities that may be considered in the
differential diagnosis include fibromatoses and certain
sarcomas.
• Occasionally phyllodes tumors can be deceptively hypocellular,
lacking the characteristic stromal fragments. This
may happen if the needle samples the focally hyalinized or
myxoid areas of the tumor. Therefore, adequate sampling
of the lesion should always be attempted by multiple
aspirations.
Intraductal Papilloma/Papillomatosis
Papilloma is a benign tumor of ductal origin, most often seen
in larger subareolar lactiferous ducts. It is most often solitary,
although multiple tumors can be seen in the peripheral breast.
Bilateral tumors are rare. Intraductal hyperplasia with papillary
architecture or “papillomatosis” is a nonspecific entity
denoting a phenotypic appearance, which should be distinguished
from a true intraductal papilloma. Less often, papilloma
comes to attention as a mass lesion (may measure up to
3 cm) in the fifth to sixth decades of life (somewhat younger
than for patients with papillary carcinoma).
Clinical Features
• Usually presents with nipple discharge, often serous or
blood-tinged