Lung tumor

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Author: Mikael Häggström [note 1]


On this resource, the following formatting is used for comprehensiveness:

  • Minimal depth
  • (Moderate depth)
  • ((Comprehensive))


Gross processing

As per presentation above.

Microscopic evaluation

Lung cancers by relative incidence.

Medical imaging provides a major clue as to whether a lung tumor is benign or malignant, where lesions smaller than 2 cm are likely to be benign, whereas lesions larger than 2 cm are malignant (that is, lung cancer) in 85% of cases.[1]

Benign tumors

Subsequently distribution of benign tumors and lung cancers, respectively, are as follows:[1]

Minute pulmonary meningothelial-like nodules (MPMNs) are interstitial nodular proliferations of small oval or spindle-shape cells in nests,[2] and do not need reporting.[image 1]

Benign lung tumors:

  • Hamartomas - 76%
  • Benign fibrous mesothelioma/solitary fibrous tumor (SFT) - 12.3%
  • Inflammatory pseudotumor (IPT) - 5.4%
  • Lipoma - 1.5%
  • Leiomyoma - 1.5%
  • Other - 3.3%

Lung cancers

TTF-1 needs to have nuclear staining on immunohistochemistry to count as positive. Cytoplasmic staining is disregarded for diagnostic purposes.[4]

Whereas large cell carcinoma is more often histologically distinct, adenocarcinoma and SCC may look alike. In such cases, an immunohistochemistry panel of TTF1, CK5/6, and p63 can be used to distinguish the two.[5][6]

Further workup

For non-small cell carcinoma (NSCLC) stages IB - IV, generally perform full next generation sequencing panel (DNA and RNA) with PDL-1 immunostaining. For advanced stage NSCLC that are not candidates for biopsy or re-biopsy, “liquid biopsy” on peripheral blood is a viable option.


  1. For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Patholines:Authorship for details.

Main page


  1. 1.0 1.1 Alain C. Borczuk (2008). "Benign Tumors and Tumorlike Conditions of the Lung ". Archives of Pathology & Laboratory Medicine 132 (7). Archived from the original. . 
  2. Kuroki, Masaomi; Nakata, Hiroshi; Masuda, Toshifumi; Hashiguchi, Norihisa; Tamura, Shozo; Nabeshima, Kazuki; Matsuzaki, Yasunori; Onitsuka, Toshio (2002). "Minute Pulmonary Meningothelial-like Nodules: High-Resolution Computed Tomography and Pathologic Correlations ". Journal of Thoracic Imaging 17 (3): 227–229. doi:10.1097/00005382-200207000-00008. ISSN 0883-5993. 
  3. Dr Nicholas Turnbull, A/Prof Patrick Emanual (2014-05-03). Squamous cell carcinoma pathology. DermNetz.
  4. Image by Mikael Häggström, MD. Source for significance: Bejarano PA, Mousavi F (2003). "Incidence and significance of cytoplasmic thyroid transcription factor-1 immunoreactivity. ". Arch Pathol Lab Med 127 (2): 193-5. doi:10.5858/2003-127-193-IASOCT. PMID 12562233. Archived from the original. . 
  5. Inamura K (2018). "Update on Immunohistochemistry for the Diagnosis of Lung Cancer. ". Cancers (Basel) 10 (3). doi:10.3390/cancers10030072. PMID 29538329. PMC: 5876647. Archived from the original. . 
  6. Affandi KA, Tizen NMS, Mustangin M, Zin RRMRM (2018). "p40 Immunohistochemistry Is an Excellent Marker in Primary Lung Squamous Cell Carcinoma. ". J Pathol Transl Med 52 (5): 283-289. doi:10.4132/jptm.2018.08.14. PMID 30235512. PMC: 6166010. Archived from the original. . 

Image sources