Non-small cell lung carcinoma
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Non-small cell lung carcinoma, abbreviated NSCLC, is a malignant epithelial neoplasm of the lung that is not small cell carcinoma of the lung.
It can be understood as a synonym for large cell carcinoma. It is umbrella term that includes squamous cell carcinoma of lung, adenocarcinoma of the lung and adenosquamous carcinoma of the lung.[1]
In the clinical context, it is usually referred to as non-small cell lung cancer; this ignores the fact that not all non-small cell lung cancer fits into the carcinoma category.
Poorly differentiated carcinoma of the lung and poorly differentiated lung carcinoma redirect to this article.
General
- Non-small cell lung carcinoma can be considered a waffle diagnosis and as such its use should be limited.
- It is preferable to be more specific if this is possible, i.e. call adenocarcinoma or squamous cell carcinoma.
- Historically, it was sufficient to differentiate between small cell and non-small cell carcinomas, as the treatment for all non-small cell lung carcinomas was the same.
- Small cell carcinoma is typically considered non-surgical disease; thus, non-small cell carcinoma or poorly differentiated carcinoma, as a diagnosis, is less likely to exclude surgery as an option.
Clinical:
- Radiologic findings should not be suggestive of a metastasis.
Microscopic
Features:
- Typically large cells with abundant cytoplasm.
- +/-Nucleoli.
- No stippled chromatin.
DDx:
- Squamous cell carcinoma of the lung.
- Adenocarcinoma of the lung.
- Small cell carcinoma of the lung.
- Large cell variant of small cell carcinoma of the lung.
- Lung metastasis - imaging suggestive of a metastasis or a history of malignancy.
IHC
Features:
- Lack of staining with neuroendocrine markers (chromogranin A -ve, synaptophysin -ve, CD56 -ve).
- Keratins +ve.
Note:
- Immunostains should not favour adenocarcinoma or squamous cell carcinoma - see Sloan-Kettering algorithm below.
Adenocarcinoma versus squamous carcinoma
Sloan-Kettering algorithm - Rekhtman et al.:[2]
| TTF-1\p63 | p63 -ve (0% of cells) | p63 +ve <50% of cells | p63 +ve >=50% of cells |
|---|---|---|---|
| TTF-1 +ve >=50% of cells | Adenocarcinoma | Adenocarcinoma | Adenocarcinoma |
| TTF-1 +ve <50% of cells | Adenocarcinoma | Adenocarcinoma | Squamous carcinoma |
| TTF-1 -ve (0% of cells) | Adenocarcinoma | CK5/6 to determine | Squamous carcinoma |
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Lung, Left Lower Lobe, Core Biopsy: - POORLY DIFFERENTIATED CARCINOMA, see comment. COMMENT: The tumour stains as follows: POSITIVE: EMA, AE1/AE3. NEGATIVE: TTF-1, chromogranin A, synaptophysin, CD56, CD45, CK5/6, p63. The morphology would be compatible with small cell carcinoma or basaloid squamous cell carcinoma. The neuroendocrine markers (chromogranin A, synaptophysin, CD56) and the squamoid markers available (p63, CK5/6) are negative; thus, the tumour is not further classified.
See also
References
- ↑ Song, Z.; Lin, B.; Shao, L.; Zhang, Y. (Sep 2013). "Therapeutic efficacy of gefitinib and erlotinib in patients with advanced lung adenosquamous carcinoma.". J Chin Med Assoc 76 (9): 481-5. doi:10.1016/j.jcma.2013.05.007. PMID 23769878.
- ↑ Rekhtman, N.; Ang, DC.; Sima, CS.; Travis, WD.; Moreira, AL. (Oct 2011). "Immunohistochemical algorithm for differentiation of lung adenocarcinoma and squamous cell carcinoma based on large series of whole-tissue sections with validation in small specimens.". Mod Pathol 24 (10): 1348-59. doi:10.1038/modpathol.2011.92. PMID 21623384.