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5 slides generated from the cancer page, with a quiz from the open benchmark and speaker notes that cite the sources. Arrow keys move between slides; Print gives one slide per page.
Large cell carcinoma is the name for a non-small-cell lung cancer whose cells look neither glandular nor squamous under the microscope. Since 2015 pathologists use protein stains to sort most of these tumours into adenocarcinoma or squamous cell carcinoma, so a true large cell diagnosis is now rare and is treated like adenocarcinoma.
The WHO classification defines large cell carcinoma as an undifferentiated non-small-cell carcinoma that lacks the cytological, architectural and immunohistochemical features of small cell carcinoma, adenocarcinoma or squamous cell carcinoma; since 2015 the diagnosis can be made only on a resection specimen after immunohistochemistry (TTF-1, napsin A, p40, p63, neuroendocrine markers) is negative or inconclusive (Travis 2015). In a study of 121 tumours across the historical spectrum of large cell carcinoma, all 47 large cell neuroendocrine carcinomas showed neuroendocrine lineage, all 24 basaloid and both lymphoepithelioma-like carcinomas showed squamous markers, and 18 of 22 clear cell carcinomas had glandular differentiation with KRAS mutations in 39 percent (Pelosi 2014); tumours with no marker at all are clinically and genomically indistinguishable from solid adenocarcinoma (Rekhtman 2014). Large cell neuroendocrine carcinoma is now classified with the neuroendocrine neoplasms.
How it differs from its parent: this is a diagnosis of exclusion within non-small-cell lung cancer rather than a lineage. Its former variants (clear cell, rhabdoid, basaloid, lymphoepithelioma-like) were reassigned in 2015, and the rhabdoid phenotype no longer exists as a category.
| Setting | Approach | Guideline |
|---|---|---|
| All stages | Treated as lung adenocarcinoma: non-squamous chemotherapy with pembrolizumab, driver testing, and the parent's stage-based pathway. | not mapped |