Dysplasia Of Pneumocyte With Non-lepidic Growth Pattern

Objective:In 2015,the World Health Organization classified the preinvasive lesions of lung adenocarcinoma into AAH(atypical adenomatous hyperplasia)and AIS(adenocarcinoma in situ).Here we describe a new abnormal lesion in the peripheral lung,which occurs in the lung parenchyma.The lesion is characterized by acinar growth,mild to moderate atypia of cells,and lacks the lepidic(adherent like)growth pattern of AAH.It can not be classified as various adenomas including bronchioloadenomas,and is significantly different from reactive atypical hyperplasia caused by inflammation in histologically.Histological morphology can not be classified as various adenomas,including bronchiolar adenomas,And obviously different from inflammation caused by reactive atypical hyperplasia.We consider the lesion to be a neoplastic atypical proliferative lesion,and tentatively named it "dysplasia of pneumocyte with non-lepidic growth pattern".The aim of this experiment was to detect the change of the driving gene of the lesion,with AAH and AIS,To determine whether the disease can be changed to "pre-invasive lesions" possibility.Methods:To identify other diseases by morphology and immunohistochemistry,Ten cases of "dysplasia of pneumocyte with non-lepidic growth pattern" were screened by this method,The other 10 cases were diagnosed as AAH and AIS.The mutation of EGFR,KRAS,NRAS,HER2,ALK fusion,ros1 fusion,BRAF,RET,met,PIK3 CA,10 driving genes were detected by RT-PCR.Results:Mutations were detected in 19(63%)of the 30 cases,including 6(60%)in 10 cases of dysplasia of pneumocyte with non-lepidic growth pattern,6(60%)in 10 cases of AAH and 7(70%)in 10 cases of AIS.The mutation types were EGFR(13 / 30),KRAS(5 / 30)and HER2(1 / 30).EGFR is the most common mutation gene type(13 /19).KRAS mutations followed(5/19)and were higher in AIS(3/7)than in dysplasia of pneumocyte with non-lepidic growth pattern(1/6).Only one case of HER2 gene mutation was found in the AIS.Conclusion:Based on the results of morphological and molecular pathological examination,dysplasia of pneumocyte with non-lepidic growth pattern are different from AAH,and the gene phenotype is very close to AAH atypical proliferative lesions.It is necessary to regard it as a precancerous lesion category of lung adenocarcinoma.