Lepidic
Summary
Lepidic growth is a pattern in which tumour cells spread along intact alveolar septa without invading stroma, vessels, or pleura, using the alveolar walls as a scaffold. It is characteristic of adenocarcinoma in situ of the lung, formerly called bronchioloalveolar carcinoma.
Detail
The term derives from the scale-like appearance of neoplastic cells lining alveolar walls. Because the underlying lung architecture is preserved and the tumour does not destroy it, lepidic-predominant lesions carry a markedly better prognosis than other adenocarcinoma patterns; pure adenocarcinoma in situ with lepidic growth and no invasion approaches 100% five-year survival after resection. Radiologically this produces ground-glass opacity rather than a solid mass, and extensive lepidic spread can mimic pneumonia on chest imaging, sometimes with bronchorrhoea. The 2011 IASLC/ATS/ERS classification retired the term bronchioloalveolar carcinoma and reclassified these lesions as adenocarcinoma in situ, minimally invasive adenocarcinoma, or lepidic-predominant invasive adenocarcinoma depending on the extent of invasion. Lung adenocarcinoma is the most common primary lung cancer in non-smokers and in women.
Sources
- Robbins Basic Pathology
- First Aid for the USMLE Step 1
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