A 68-year-old woman presents with a 3 cm well-circumscribed breast mass. Histology shows tumor cells arranged in large nests with abundant extracellular mucin pools and low mitotic activity. Which of the following is the most likely diagnosis?

• A Medullary carcinoma
• B Papillary carcinoma
• C Tubular carcinoma
• D Mucinous (colloid) carcinoma ✓

Explanation

Mucinous (colloid) carcinoma is characterized by tumor nests floating in abundant extracellular mucin pools. It occurs in older women, has a well-circumscribed gross appearance, and carries a favorable prognosis. Medullary carcinoma shows dense lymphoplasmacytic infiltrate without mucin. Tubular carcinoma shows angulated glands. Papillary carcinoma shows arborizing papillae. Mucinous carcinoma is a recognized subtype in Robbins.

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.