A 22-year-old woman has a 2 cm, well-circumscribed, mobile breast mass. Core biopsy shows a biphasic tumor with both stromal and epithelial components. The stromal cells show low cellularity and no atypia. Which statement about this lesion is correct?
- A It carries a high risk of progression to invasive carcinoma
- B It is a phyllodes tumor requiring wide excision
- C It is a fibroadenoma, a benign biphasic neoplasm ✓
- D It shows loss of the myoepithelial layer on p63 immunostain
Correct answer: C. It is a fibroadenoma, a benign biphasic neoplasm
Explanation
Fibroadenoma is a common benign biphasic tumor in young women, composed of both stromal and epithelial elements. It does not carry significant malignant potential. Phyllodes tumor shows increased stromal cellularity, overgrowth, and mitoses. Loss of myoepithelial layer (p63 negative) is a feature of invasive carcinoma, not fibroadenoma.
Reference: Rosai and Ackerman's Surgical Pathology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.