A breast biopsy shows ducts and lobules surrounded by a cellular spindle-cell stroma with a leaf-like cleft architecture. The correct diagnosis and its biological behaviour is:

• A Invasive ductal carcinoma — malignant, requires mastectomy
• B Phyllodes tumor — ranges from benign to malignant; treated by wide local excision ✓
• C Fibroadenoma — entirely benign; managed conservatively
• D Sclerosing adenosis — benign; no specific treatment needed

Explanation

Phyllodes tumor (cystosarcoma phyllodes) is a fibroepithelial neoplasm with characteristic leaf-like clefts and a hypercellular stroma that may be benign, borderline, or malignant based on stromal cellularity, mitoses, nuclear atypia, and margin status. Unlike fibroadenomas, phyllodes tumors grow rapidly and require wide excision with clear margins to prevent local recurrence; malignant phyllodes can metastasize hematogenously.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.