A 65-year-old non-smoker woman is found to have a peripheral lung adenocarcinoma growing along existing alveolar walls without destroying the architecture (non-invasive growth pattern). This pattern is termed:
- A Lepidic growth pattern adenocarcinoma (formerly bronchioloalveolar carcinoma) ✓
- B Micropapillary adenocarcinoma
- C Solid adenocarcinoma with mucin production
- D Acinar adenocarcinoma with central fibrosis
Explanation
The lepidic growth pattern describes tumor cells growing along pre-existing alveolar walls (pneumocyte scaffold) without stromal, vascular, or pleural invasion. This corresponds to the previously termed 'non-mucinous bronchioloalveolar carcinoma.' When confined entirely to lepidic growth in a lesion ≤3 cm with no invasion, it is called adenocarcinoma in situ (AIS) with near-100% cure rate. Minimally invasive adenocarcinoma has ≤5 mm invasion. Lepidic-predominant invasive adenocarcinoma carries a better prognosis than acinar, papillary, micropapillary, or solid subtypes. This pattern is more common in non-smokers and EGFR/KRAS-mutated tumors.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.