November 27, 2022

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WHO 2021 classification: Lung adenocarcinoma in situ was excluded from lung malignant tumors

New WHO 2021 classification: Lung adenocarcinoma in situ was excluded from lung malignant tumors



 

 

New WHO 2021 classification: Lung adenocarcinoma in situ was excluded from lung malignant tumors. 

The new WHO classification of lung tumor tissues in 2021, which is expected by the majority of respiratory, thoracic surgery, and pathologists, was launched in March this year, and the previous version was 2015. WHO is currently recognized as a classification method for lung tumors.



01. Update interpretation

 

New WHO 2021 classification: Lung adenocarcinoma in situ was excluded from lung malignant tumors

Image source: WHO 2021 new classification of lung tumor tissues

 

The biggest update this time is that lung adenocarcinoma in situ has been excluded from the category of lung malignant tumors. The WHO 2021 classification of lung adenocarcinoma is as follows:

 

Glandular precursor lesions

  • Atypical adenomatous hyperplasia
  • Adenocarcinoma in situ

 

Adenocarcinoma

  • Microinvasive adenocarcinoma
  • Invasive non-mucinous adenocarcinoma
  • Invasive mucinous adenocarcinoma
  • Colloid adenocarcinoma
  • Fetal adenocarcinoma
  • Intestinal adenocarcinoma

 

We can see that adenocarcinoma in situ, like atypical adenomatous hyperplasia, falls into the category of glandular precursor lesions (also known as pre-glandular lesions).

Adenocarcinoma is a malignant tumor of epithelial origin. It is divided into micro-invasive adenocarcinoma, invasive mucinous adenocarcinoma, and invasive non-mucinous adenocarcinoma (here subdivided into acinar, papilla, solid, and micropapillary). Kind of type.

In this case, lung adenocarcinoma in situ is not lung adenocarcinoma! ! Philosophically, the sophistry that white horses are not horses is established! !

 

 

 



02. How to deal with

 

So, as a precancerous lesion, does lung adenocarcinoma still need surgery? Experts from various fields have different opinions on this. Here, I will talk about my personal experience and opinions.

 

Emphasize the characteristics of adenocarcinoma in situ: slow growth, no metastasis, and no danger to the body temporarily. Its CT appearance is 5-30 mm pure ground glass nodules (pGGN) with uniform density and CT value below -600. There are very few vacuoles, burrs, pleural traction and lobes, and blood vessels can pass through, but No blood vessel curvature.


For pure ground glass nodules larger than 10 mm, the diagnosis of adenocarcinoma in situ requires caution. Adenocarcinoma in situ of the lung is generally less than 10 mm.

 

Of course, whether it is adenocarcinoma in situ, it must be excised for pathology to be finally diagnosed. Although the prognosis of microinvasive adenocarcinoma is similar to that of adenocarcinoma in situ, it is still malignant in pathology, and it is necessary to beware of the possibility of misjudgment on imaging.

 

Although there are different opinions, after the publication of the WHO new classification of lung tumor tissues in 2021, it is of great significance to guide us in the treatment of ground-glass lung nodules.

 

First of all, carcinoma in situ is not a malignant tumor, so there is strong evidence that carcinoma in situ does not require surgery.

 

Micro-invasive adenocarcinoma is an early malignant tumor with a good prognosis. There is basically no recurrence after resection, and it can also be observed. The decision to remove or not can be based on the risk of the nodule itself, the patient’s wishes, and the risk of surgery.

 

 

 

New WHO 2021 classification: Lung adenocarcinoma in situ was excluded from lung malignant tumors

(source:internet, reference only)


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