A 50-year-old woman presents with a 3 cm breast mass. Core biopsy reveals a lesion characterized by monomorphic cells with intracytopmic lumina, growing in a cribriform and micropapillary pattern within a lobule, with intact myoepithelial cells on p63 immunohistochemistry. No invasion is identified. What is the diagnosis?
- A Lobular carcinoma in situ ✓
- B Atypical ductal hyperplasia
- C Low-grade ductal carcinoma in situ
- D Tubular carcinoma
Correct answer: A. Lobular carcinoma in situ
Explanation
Lobular carcinoma in situ (LCIS) shows monomorphic cells with intracytopmic lumina expanding lobules, with intact myoepithelial cells. DCIS involves ducts, not lobules. Atypical ductal hyperplasia is a partial ductal proliferation smaller than DCIS. Tubular carcinoma is an invasive carcinoma with angulated glands in a desmoplastic stroma.
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.