Diagnostics

• The most common breast tumor in women < 35 years of age

• Peak incidence: 20–30 years

• Idiopathic

• Possible hormonal etiology (increased estrogen, e.g., during pregnancy may stimulate growth )

• Usually a well-defined, mobile mass

• Most commonly solitary

• Nontender

• Rubbery consistency

• Typically 1–2 cm in diameter

• Giant fibroadenomas are > 5 cm in size and may distort the shape of the breast.

• Breast ultrasound: well-circumscribed oval or round hypoechoic solid mass

• Mammography

  • Round mass with a well-defined border

  • May have popcorn-like calcifications

• Indications (not routinely indicated): imaging or clinical findings suspicious for malignancy or phyllodes tumor

• Modalities: core needle biopsy, fine needle aspiration, or excisional biopsy

• Findings: fibrous and glandular tissue

Biopsy is not routinely required in patients with imaging findings consistent with a fibroadenoma and no clinical suspicion of malignancy or phyllodes tumor.

Core needle biopsy or excisional biopsy is preferred if phyllodes tumor is suspected as FNAC cannot reliably distinguish between fibroadenomas and phyllodes tumors.

• Phyllodes tumor

  • Tend to be larger in size

  • Often grow more rapidly than fibroadenomas

  • Usually occur in women ∼ 40 years of age

• Other benign breast lesions (e.g., breast cysts)

• Breast cancer

The clinical and imaging features of phyllodes tumors may closely resemble those of fibroadenomas, but the biological behaviors of these tumors are different. Borderline and malignant phyllodes tumors can metastasize hematogenously, and benign phyllodes tumors have a high risk of recurrence postexcision.