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Lung tumor

Adenocarcinoma-general


Reviewer: Deepali Jain, M.D. (see Reviewers page)
Revised: 8 April 2013, last major update September 2012
Copyright: (c) 2003-2013, PathologyOutlines.com, Inc.

See revised Adenocarcinoma classification system

General
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● Arises from terminal bronchioles
● Most common subtype in nonsmokers
● In US, 50% of lung carcinomas in women are adenocarcinoma
● 80% contain mucin
● Molecular Testing Guideline for Selection of Lung Cancer Patients for EGFR and ALK Tyrosine Kinase Inhibitors: Guideline from the College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology, Molecular testing guidelines for EGFR and ALK tyrosine kinase inhibitors: 2013 guidelines, click here

Clinical features
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● May be associated with scarring
● Grows slower than squamous cell
● 5 year survival: stage I - 69%, II - 40%, IIIA - 17%, IIIB - 5%, IV - 8%
● More likely TTF1 negative in males or smokers

Gross description
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● Poorly circumscribed gray-yellow lesions, single or multiple, may be mucoid
● 77% involve visceral pleura producing puckering/pleural retraction, 65% are peripheral
● Usually not cavitary
● Often associated with a peripheral scar or honeycombing (scar appears to be response to tumor)
● Rarely spreads into pleural space to coat visceral and parietal pleura and resemble diffuse mesothelioma

Gross images
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Peripheral tumor

Micro description
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● Glandular differentiation with tubules or papillae and mucin secretion
● Either in situ, minimally invasive or invasive (mucinous or serous)
● Subtypes indicated below
● Tumors 1.5 cm or less are usually one cell type, larger tumors are often mixed
● Vascular invasion common
● Rarely choriocarcinoma foci, pagetoid spread along bronchial mucosa, eosinophilic intracytoplasmic globules, clear cell change (glycogen)
● Periphery of tumor often has minimal atypia, with marked atypia centrally
● Ciliated / non-terminal respiratory unit type: see Mod Pathol 2012;25:1265

Cytology images
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Pleomorphic cells with cytoplasmic intranuclear inclusion

Virtual slides
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Peripheral tumor


Moderately differentiated adenocarcinoma

Positive stains
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● Mucin, low molecular weight keratin (CK7), EMA, CEA, TTF1 (72%, Am J Surg Pathol 2002;26:767)
● Also surfactant apoprotein (50%), mesothelin (50%), vimentin (9%), S100 (Langerhans cells), p53, CD57/Leu7 (50% of well/moderately differentiated tumors), calretinin (11%, Am J Surg Pathol 2003;27:150)
● Also EGFR mutation specific antibodies (variable, Lung Cancer 2012;77:299)

Negative stains
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● CK20, keratin 5 (usually), P504S, p63 (cytoplasmic expression associated with bad prognosis, Histopathology 2006;49:349)

Electron microscopy description
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● Goblet cells, mucus cells, nonciliated bronchiolar cells, Clara cells

Molecular description
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● EGFR mutation: exon 21 L858R and exon 19 deletion (predictor of response to tyrosine kinase inhibitors, Arch Pathol Lab Med 2012;136:504), Kras mutation (with mucinous adenoca), ALK-1 mutation (extensive signet ring morphology)

Differential diagnosis
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● Melanoma (may be mucin positive)

End of Lung tumor > Adenocarcinoma-general


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