Adenocarcinoma in situ of the lung

Adenocarcinomas in situ (AIS) of the lung refer to a relatively new entity for a pre-invasive lesion in the lung. This entity partly replaces the noninvasive end of the previous term bronchoalveolar carcinoma. Adenocarcinoma in situ is defined as a localised adenocarcinoma of <3 cm that exhibits a lepidic growth pattern, with neoplastic cells along the alveolar structures but without stromal, vascular, or pleural invasion 1.

AISs are localised adenocarcinomas of ≤3 cm, with no growth pattern other than lepidic, with neoplastic cells along the alveolar structures but without stromal, vascular, lymphatic, or pleural invasion, and no features of necrosis 6

There are three histopathological subtypes, the most common is non-mucinous, with mucinous or mixed subtypes being rarely found. 

While adenocarcinoma in situ is usually seen as a pure ground-glass nodule or a part-solid lung nodule, there can be overlap among the imaging features of atypical adenomatous hyperplasia, adenocarcinoma in situ, and invasive adenocarcinoma of the lung 1.

Adenocarcinomas in situ are commonly associated with PET false-negative results. FDG PET/CT is recommended when assessing subsolid ground-glass lung lesions that have a solid component measuring more than 8 mm 5

Adenocarcinoma in situ carries an excellent prognosis, with reported survival rates of 100% following complete tumor resection 6.

Lung cancer
Share article

Article information

rID: 22176
System: Chest, Oncology
Synonyms or Alternate Spellings:
  • Adenocarcinoma in situ (AIS) of lung
  • AIS of lung
  • AIS lung
  • AIS
  • Adenocarcinoma in situ (lung)
  • Adenocarcinoma in situ of lung
  • Adenocarcinoma in situ (AIS) of the lung

Support Radiopaedia and see fewer ads

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.