Lung tumor
Adenocarcinoma overview

Topic Completed: 6 June 2019

Minor changes: 11 August 2020

Copyright: 2019-2020,, Inc.

PubMed Search: Adenocarcinoma general[title] AND (free full text[sb])

Caroline I.M. Underwood, M.D.
Carolyn Glass, M.D., Ph.D.
Page views in 2019: 38,822
Page views in 2020 to date: 25,909
Cite this page: Underwood C, Musick A, Glass C. Adenocarcinoma overview. website. Accessed August 15th, 2020.
Definition / general
  • Non small cell lung carcinoma with glandular differentiation, mucin production, or pneumocyte marker expression
Essential features
  • Most prevalent non small cell lung carcinoma
  • Five histologic patterns (acinar, papillary, micropapillary, lepidic, solid); mucinous and non mucinous subtypes
  • Positive for TTF1
  • Terminology of lung adenocarcinoma has been significantly revised in the new WHO classification (IARC: WHO Classification of Tumours of the Lung, Pleura, Thymus and Heart (Medicine), 4th Edition, 2015, J Thorac Oncol 2015;10:1243)
    • Discontinuing the terms bronchioloalveolar carcinoma (BAC) and mixed subtype adenocarcinoma
    • Addition of adenocarcinoma in situ (AIS) as a preinvasive lesion to join atypical adenomatous hyperplasia
    • Addition of minimally invasive adenocarcinoma,
    • Use of the term "lepidic" for a noninvasive component (previously classified as BAC) of an invasive adenocarcinoma
    • Introducing the term "invasive mucinous adenocarcinoma" for adenocarcinomas formerly classified as mucinous BAC, excluding tumors that meet criteria for AIS or MIA
    • Discontinuing the subtypes of clear cell and signet ring adenocarcinoma
    • Discontinuing the term mucinous cystadenocarcinoma and including these under the category of colloid adenocarcinoma
ICD coding
  • 8046/3 - non small cell carcinoma of bronchus or lung (international code)

  • C34.90 - malignant neoplasm of unspecified part of unspecified bronchus or lung
Diagrams / tables

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Histologic subtyping for surgeon

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Histologic pattern and prognosis

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Clinical features
  • Cough, (productive if mucinous adenocarcinoma [Chest 2012;142:1338]), hemoptysis, dyspnea, weight loss, chest pain
  • Paraneoplastic / endocrine syndromes are much less common than in small cell lung carcinoma
    • Hypertrophic pulmonary osteoarthropathy with clubbing of the fingers, symmetric polyarthritis, periostitis of the long bones (World J Clin Oncol 2014;5:197)
  • Histological, based on morphology and staining pattern
Radiology description
Radiology images

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Mucinous adenocarcinoma (Fig 3a)

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Axel lung window (Case 4)

Prognostic factors
Case reports
  • NCCN Guidelines 3.2018
  • For stages I, II, IIA: surgical resection (preferred) + adjuvant chemotherapy (platinum based) and radiation
  • Inoperable or metastatic: chemotherapy variable radiation
Gross description
Gross images

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Peripheral adenocarcinoma

Frozen section description
Frozen section images

Contributed by Caroline Mullins Underwood, M.D.
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Mucinous lung adenocarcinoma

Microscopic (histologic) description
Microscopic (histologic) images

Contributed by Caroline Mullins Underwood, M.D., Andrey Bychkov, M.D., Ph.D. and Fulvio Lonardo, M.D.
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Adenocarcinoma in situ

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Acinar pattern

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Lepidic pattern, architecture

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Lepidic pattern, cytologic features

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Micropapillary pattern

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Papillary pattern

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Solid pattern, architecture

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Solid pattern, cytologic features

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Mucinous subtype, architecture

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Mucinous subtype, cytologic features

Positive PDL1

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Negative PDL1

ADC cocktail

Virtual slides

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Resection specimen

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Core needle biopsy

Cytology description
  • 3-D clusters of cohesive cells; foamy / vacuolated cytoplasm; fine chromatin; variable prominent nucleoli (J Thorac Oncol 2011;6:244)
  • Usually on pleural effusions or needle washes
Cytology images

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Large malignant cells

Positive stains
Negative stains
Electron microscopy description
Molecular / cytogenetics description
Molecular / cytogenetics images

Case of the Week #425

ALK break apart FISH images (ALK gene in RED)

Sample pathology report
  • Lung, left upper lobe, wedge resection:
    • Invasive adenocarcinoma, acinar predominant with secondary solid growth pattern (see synoptic report)
Differential diagnosis
Board review style question #1

    A 59 year old man presents with cough, hemoptysis and shortness of breath. A mass in his left lung was biopsied. Which of the following statements about this disease is true?

  1. Exposure to benzene is an important risk factor in the development of this disease
  2. Masses are most frequently found in central / hilar regions of both lungs
  3. The growth pattern indicated in the patient’s biopsy above is a poor prognostic factor
  4. The most common site of metastasis is the liver
  5. This disease has a higher incidence in men than in women
Board review answer #1
C. The H&E stain demonstrates a micropapillary pattern, which is a poor prognostic factor. Lung adenocarcinoma is associated with exposure to radon, not benzene, and is typically found in the peripheral regions or upper lobes of the lung. This cancer is also more common in women than in men and most frequently metastasizes to the brain, not the liver.

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Reference: Adenocarcinoma - General
Board review style question #2
    A 63 year old woman presented with mass in the upper lobe of her left lung with enlargement of the mediastinal lymph nodes. Surgical biopsy shows columnar tumor cells with abundant intracytoplasmic mucin in an acinar growth pattern. The malignant cells are most likely to be positive for which of the following mutations?

  1. ALK rearrangement
  2. BRAF
  3. EGFR
  4. HER2 amplification
  5. KRAS
Board review answer #2
E. KRAS is the most common mutation associated with mucinous adenocarcinoma (76%). EGFR mutations are rare in the mucinous subtype. ALK, HER2 and BRAF are uncommon mutations overall.

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Reference: Adenocarcinoma - General
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