A 24-year-old woman presents with a firm, well-circumscribed, highly mobile 2 cm breast lump that is not fixed to skin or fascia. Excision biopsy shows a biphasic lesion composed of compressed epithelial-lined clefts within a cellular but uniform fibroblastic stroma. What is the diagnosis?

• A Radial scar
• B Phyllodes tumor
• C Invasive ductal carcinoma
• D Fibroadenoma ✓

Explanation

Fibroadenoma is the most common benign breast tumor in women under 30 years. It is a biphasic lesion with a uniform, non-atypical stroma compressing glands into slit-like intracanalicular or rounded pericanalicular patterns, and it is clinically mobile, classically called a breast mouse. Phyllodes tumor is excluded by its leaf-like architecture, stromal overgrowth, atypia and mitoses, which are absent here.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.