NSCLC - No Pictures Flashcards
Histologic types of NSCLC
- Squamous cell
- Bronchioloalveolar
- Adenocarcinoma
- Large cell
- Adenosquamous
- Lymphoepithelioma-like
- Rhabdoid
- Sarcomatoid/pleomorphic
Unlike adenocarcinoma, squamous cell carcinoma progresses through. . .
. . . clear, definable stages of pre-malignant lesion
Mild dysplasia -> moderate dysplasia -> severe dysplasia / CIS
Classification of squamous cell carcinoma of the lung
Classified as “well-“, “moderately-“, or “poorly-“ differentiated.
The main features to look for are the presence/absence of keratinization or intercellular bridges.
Squamous cell carcinoma of the lung IHC
keratin5/6+
p63+
p40+
syapto/chormo negative (but may have focal positivity)
TTF1 negative
CD117/cKit sometimes positive, sometimes negative
PDL1 in lung malignancies
Squamous cell: Most are PDL1+
Lung cancer most associated with smoking
Squamous cell carcinoma
What makes an adenosquamous carcinoma?
Mixed adenocarcinoma and squamous carcinoma features within the SAME tumor mass (NOT separate nodules). The minor feature represents at least 5% of the total tumor.
Both components have been demonstrated to arise from the same clone by mutational analysis.
Lymphoepithelial carcinoma immunophenotype
When we stain LEC, we are trying to differentiate it from metastatic LEC from another site and thymic neoplasms.
Pulmonary LEC: EBER ISH+, AE1/AE3+, EMA+, CEA+, TTF-1 negative
Thymic LEC-like carcinoma: Usually EBER ISH negative, CD5+, CD117/cKIT+
“Bronchoalveolar carcinoma”
This term is no longer used!
Now, it has been replaced with “pulmonary adneocarcinoma in-situ)
Post-chemotherapy vs post-immunotherapy changes
Post-chemotherapy: Hyalinized fibrosis
Post-immunotherapy: Fibrosis with intervening lymphocytes and lymphoid aggregates.
In order to make a diagnosis of enteric-type or colloid variant lung adenocarcinoma, you need to see. . .
. . . At least 50% of the tumor with either pools of extracellular mucin or enteric morphology.
