Analysis And Comparison Of Five Clinicopathological Diagnostic Methods For Pulmonary Sclerosing Pneumocytoma

Background and purposePulmonary sclerosing pneumocytoma(PSP)is a rare slow-growing benign tumor of the lung,some scholars believe that it has low malignant potential.It was first reported by Leibow et al.In 1956.With the development of its research,it is believed that it originates from type ? pneumocytes.In this paper,five diagnostic methods of PSP were studied: routine surgical excision,intraoperative rapid frozen specimens,needle biopsy,Endobronchial ultrasound-guided transbronchial needle aspirationbiopsy(EBUS-TBNA),and fine needle aspiration cytology.The clinical and pathological diagnostic methods of PSP were comprehensively analyzed from different angles to avoid misdiagnosis.MethodWe collected cases of PSP diagnosed in the First Affiliated Hospital of Zhengzhou University from August 2011 to October 2018,including 97 cases of routine surgical specimens,85 cases of intraoperative rapid frozen section specimens,121 cases of puncture biopsy,6 cases of EBUS-TBNA,and 176 cases of corresponding fine needle aspiration cytology.We analyse clinical and radiological data with the use of HE staining and immunohistochemical staining to discuss the clinicopathological features of PSP.Statistical software SPSS 23.0,Pearson Chi-square test and Fisher's exact probabilities method were used to analyze the difference of the diagnostic rate of five clinicopathological diagnostic methods.Test level ?=0.05.Result1.The boundary between PSP and surrounding lung tissue was clear,and the section was mostly grey-white or grey-red.Four histological conformations were often seen in PSP,solid area,papillary area,sclerosis area and hemorrhagic(hemangioma-like)area.Cuboidal epithelial cells and polygonal stromal cells are two kinds of tumor cells.Cuboidal cells have various shapes,sizes and some pleomorphism,while polygonal interstitial cells are relatively uniform in size,mild in shape and slightly atypical.The interstitium of papilla is different from the fibrovascular axis of lung cancer.2.TTF-1,EMA and ?-Catenin were expressed in both cuboidal epithelial cells and polygonal cells;CK7 and NapsinA were expressed in epithelial cells;EMA was strongly positive,but Vimentin was not expressed or rarely expressed;Vimentin was positive in round cells but EMA and AE1/AE3(CK)were weak;neuroendocrine markers CgA,Syn and CD56 were mostly negative,with a few cases weakly positive,Ki-67 proliferation index was generally less than 5%.3.The four histological conformations of the specimens excised by routine surgery are relatively comprehensive.Papillary structure and solid area are the most common structures.With gross appearance,imaging,routine staining and immunohistochemistry,it is easy to make a definite diagnosis.4.Most of intraoperative rapid frozen specimens were lobes or wedge-shaped resection specimens.The tumors were round or quasi-circular solitary masses with clear boundaries with surrounding lung tissues.Some of them were covered with a smooth capsule.In the gray-grey-red matter of the cut surface,they could be accompanied by bleeding and fibrocystic changes.Due to frozen,the tissue structure and cell morphology are seriously deformed.In some cases,cell atypia is larger,cell density is increased,alveolar epithelium is significantly proliferated,and it is easy to be misdiagnosed as adenocarcinoma.5.Needle biopsy often shows only parts of the histological structure and cytological characteristics because of the limited number of specimens,and even some specimens only show one of the four histological conformations.Sclerosing stroma,papillary characteristics,cellular diversity,nested or diffuse distribution are important clues to distinguish adenocarcinoma from adenocarcinoma.6.EBUS-TBNA specimens usually shows abundant cells with minimal atypia around small vessels or strip collagen,showing small adenoid arrangement and are scattered,easier to be misdiagnosed as lung cancer than fine needle aspiration specimens.Immunohistochemistry has important application value.7.Cytological specimens are usually scattered in small nest-like epithelioid cells with small to medium size,cells are round,oval or polygonal,with unclear cell boundaries,fine granular chromatin,clear nuclear contour,few has small nucleoli,some of them with atypia,which are easily misdiagnosed as malignant tumor cells.8.The diagnostic rate of intraoperative rapid freezing and puncture biopsy(75.3% and 93.1%)was slightly lower than that of surgical excision(100%)(P<0.05).The diagnostic rate of EBUS-TBNA in this group was 100%,but the number of specimens was small,requires more data analysis and support.However,needle aspiration cytology has few cells with almost no structure,which makes it difficult to make a definite diagnosis.It is suggested that needle aspiration cytology should not be used to diagnose PSP.Conclusionintraoperative rapid frozen specimens are easily to be misdiagnosed due to their large variants and atypia of cells.It is necessary to pay attention to gross sampling and clinical imaging features.Needle biopsy,EBUS-TBNA and cytology are easily misdiagnosed as lung adenocarcinoma because of the fragmentation of specimens or the small amount of tissue or cells.Immunohistochemistry is of great significance for the definite diagnosis of needle biopsy,EBUS-TBNA and resected specimens.