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.

Non-small cell lung carcinoma
Diagnosis in short

Synonyms large cell carcinoma (term discouraged by some authorities)
LM DDx lung adenocarcinoma, lung squamous carcinoma, lung small cell carcinoma, poorly differentiated metastatic carcinoma
IHC pankeratin +ve, CD56 -ve, chromogranin A -ve, synaptophysin -ve
Staging lung cancer staging
Site lung - see lung tumours

Prevalence uncommon
Prognosis usually poor

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:

IHC

Features:

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

  1. 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.
  2. 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.