Subtype groups with the most frequent PD-L1 expression included solid (25 of 36; 69%), micropapillary (7 of 14; 50%), and lepidic
(11 of 23; 48%).
There was also a focal lepidic
pattern of growth seen at the periphery of the specimen.
In lung adenocarcinoma, nuclear maspin was shown to be a typical feature of the lepidic
growth pattern, whereas increased and combined nuclear and cytoplasmic maspin followed by the loss of maspin characterized the invasive phenotype .
DISCUSSION: Bronchiolo-Alveolar carcinoma, now termed as lepidic
predominant adenocarcinoma is a slow growing malignancy which can have varied presentations.
In addition, bronchorrhea and the unusual pattern of lepidic
growth of the bronchoalveolar carcinoma can worsen hypoxaemia by impairing diffusion capacity of oxygen.
It is defined as a primary lung cancer in a peripheral location and growing in a lepidic
(scalelike) style by the alveolar septae without parenchymal, vascular or pleural invasion .
At this point, radiologic ground-glass lesions that ultimately have lepidic
architecture will be slightly raised relative to the adjacent lung parenchyma and have a slight difference in color.
4) Three major categories that require separate staging criteria include adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma, and invasive, lepidic
predominant adenocarcinoma (MIA).
Finally, the histologic features and differential diagnoses of lepidic
tumors, and reactive and benign lesions were reviewed in much detail.
The only discrepant case in our study was a lung biopsy from a patient with a diagnosis of adenocarcinoma with lepidic
EGFR mutations are found more often in tumors with lepidic
, papillary, micropapillary, and acinar growth patterns, whereas ALK rearrangement is associated with solid, signet ring, and mucinous phenotypes.
Tumors with an original diagnosis of bronchioloalveolar carcinoma were reclassified as adenocarcinoma with lepidic
growth pattern per the 2015 World Health Organization criteria.