Adenocarcinoma of the lung is one of the non-small cell carcinomas of the lung and is a malignant tumour with glandular differentiation or mucin production. This tumour exhibits various patterns and degrees of differentiation, including lepidic, acinar, papillary, micropapillary and solid with mucin formation 1.
It is now considered the most common histological subtype in terms of prevalence.
Early symptoms are fatigue with mild dyspnoea followed by chronic cough and haemoptysis at a later stage.
Classification of the tumour subtype is based on the estimate of the percentage of histologic patterns and the predominant subtype. The terminology of mixed subtype is to be avoided:
- lepidic predominant adenocarcinoma of lung (formerly non-mucinous bronchioloalveolar carcinoma (BAC) pattern, with >5 mm invasion)
- acinar predominant adenocarcinoma of lung
- papillary predominant adenocarcinoma of lung
- micropapillary predominant adenocarcinoma of lung
- solid predominant with mucin
Variants of invasive adenocarcinoma
- invasive mucinous adenocarcinoma (formerly mucinous BAC)
- fetal (low and high grade)
Sometimes it is impossible to radiographically distinguish between other histological lung cancer types.
A lung nodule is a rounded or irregular region of increased attenuation measuring less than 3 cm. The amount of attenuation can further classify the nodules as either ground glass, sub-solid or solid.1,2
Histologically, the ground-glass attenuation corresponds to a lepidic growth pattern and the solid component correspond to invasive patterns. Hence the preinvasive category of AIS, MIA, and the invasive subtype of LPA is often seen as ground glass nodule or sub-solid nodule with a predominant ground-glass component. On the other hand, the remaining invasive subtypes of adenocarcinoma is usually a solid nodule but may also subsolid and only occasionally seen as ground glass nodule 1,2.
Invasive mucinous adenocarcinoma subtype (formerly mucinous BAC) can have a variable appearance ranging from consolidation, air bronchograms or seen as multifocal subsolid nodules or masses 2.
Treatment and prognosis
Recommendation for follow-up of solid nodules is as per Fleischner Society guidelines. Recommendation for ground glass or subsolid nodules has recently been proposed, please consult Naidich et article - Recommendations for the management of sub-solid pulmonary nodules detected at CT: a statement from the Fleischner Society 3.
lung cancer: overview
non small-cell lung cancer
- adenosquamous carcinoma
- large cell carcinoma
- primary sarcomatoid carcinoma of lung
- squamous cell carcinoma
- salivary gland type tumours
- pulmonary neuroendocrine tumours
- preinvasive lesions
- benign neoplasms
- pulmonary metastases
- lung cancer screening
- lung cancer staging
- non small-cell lung cancer
- 1. Travis WD, Brambilla E, Noguchi M et-al. International association for the study of lung cancer/american thoracic society/european respiratory society international multidisciplinary classification of lung adenocarcinoma. J Thorac Oncol. 2011;6 (2): 244-85. doi:10.1097/JTO.0b013e318206a221 - Pubmed citation
- 2. Austin JH, Garg K, Aberle D et-al. Radiologic implications of the 2011 classification of adenocarcinoma of the lung. Radiology. 2013;266 (1): 62-71. doi:10.1148/radiol.12120240 - Pubmed citation
- 3. Naidich DP, Bankier AA, Macmahon H et-al. Recommendations for the management of subsolid pulmonary nodules detected at CT: a statement from the Fleischner Society. Radiology. 2013;266 (1): 304-17. doi:10.1148/radiol.12120628 - Pubmed citation
- 4. Aoki T, Tomoda Y, Watanabe H et-al. Peripheral lung adenocarcinoma: correlation of thin-section CT findings with histologic prognostic factors and survival. Radiology. 2001;220 (3): 803-9. Radiology (full text) - doi:10.1148/radiol.2203001701 - Pubmed citation
- 5. Lee SM, Goo JM, Park CM et-al. A new classification of adenocarcinoma: what the radiologists need to know. Diagn Interv Radiol. 2012;18 (6): 519-26. doi:10.4261/1305-3825.DIR.5778-12.1 - Pubmed citation