Invasive mucinous adenocarcinoma of the lung is a subtype of invasive adenocarcinoma of the lung formerly known as mucinous bronchoalveolar carcinoma (BAC). They are more likely to be multicentric and tend to have a worse prognosis than non-mucinous types.
In 2011, the International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS) 4 introduced a new classification and terminology for adenocarcinoma of the lung. The term bronchoalveolar carcinoma (BAC) has been extinct and, invasive mucinous adenocarcinoma of the lung now replaces the tumors previously known as mucinous bronchoalveolar carcinoma (BAC).
Mucinous carcinomas are commonly multicentric, multilobar, and may show bilateral lung involvement 3,4. These patterns may indicate aerogenous spread 4.
Mucinous carcinomas originate from columnar mucus-containing cells (cf. non-mucinous tumors which arise from club cells (Clara cells) or type 2 pneumocytes), showing a goblet or columnar cell morphology with abundant intracytoplasmic mucin 3,4. The alveoli are usually filled with mucin 4.
Although also consisting of a mixture of histologic patterns, e.g. lepidic, acinar, papillary, micropapillary, and solid growth, as we observe in the nonmucinous invasive tumors, there is no recommendation to subcategorise the invasive mucinous adenocarcinomas, as its clinical relevance is still uncertain 4.
- KRAS mutation: strongly present (~76%) 4,5
- EGFR mutation (epidermal growth factor receptor): almost always absent (~3%) 4,5
- 1. 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. Radiology (full text) - doi:10.1148/radiol.12120240 - Pubmed citation
- 2. Kadota K, Yeh YC, D'Angelo SP et-al. Associations between mutations and histologic patterns of mucin in lung adenocarcinoma: invasive mucinous pattern and extracellular mucin are associated with KRAS mutation. Am. J. Surg. Pathol. 2014;38 (8): 1118-27. doi:10.1097/PAS.0000000000000246 - Pubmed citation
- 3. Lee KS, Kim Y, Han J et-al. Bronchioloalveolar carcinoma: clinical, histopathologic, and radiologic findings. Radiographics. 1997;17 (6): 1345-57. doi:10.1148/radiographics.17.6.9397450 - Pubmed citation
- 4. 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
- 5. Tang ER, Schreiner AM, Pua BB. Advances in lung adenocarcinoma classification: a summary of the new international multidisciplinary classification system (IASLC/ATS/ERS). (2014) Journal of thoracic disease. 6 (Suppl 5): S489-501. doi:10.3978/j.issn.2072-1439.2014.09.12 - Pubmed
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