Bronchioloalveolar carcinoma (now termed lepidic-predominant adenocarcinoma) shows a characteristic growth pattern that distinguishes it from invasive adenocarcinoma. This pattern is:

• A Forming glandular structures within the lung parenchyma, invading stroma and vessels
• B Tumor cells growing along pre-existing alveolar walls (lepidic growth) without stromal, vascular, or pleural invasion ✓
• C Central mass with post-obstructive pneumonia and hilar lymphadenopathy
• D Diffuse bilateral consolidation mimicking pneumonia due to airspace filling by mucin

Explanation

Lepidic growth means tumor cells (Clara cells or type II pneumocytes) spread along intact alveolar walls without destroying the architecture or invading stroma, lymphatics, or pleura. This is the defining feature distinguishing lepidic adenocarcinoma from invasive types. When invasion is present, it becomes invasive adenocarcinoma. Option D describes mucinous adenocarcinoma (formerly mucinous BAC), which is a subtype.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.