| [Objective]This research is aimed at exploring the significance of pathological parameters,including pathomorphology,immunohistochemistry,special staining and molecular detection,in the diagnosis and differential diagnosis of salivary adenoid cystic carcinoma(ACC)and basal cell adenoma(BCA).It is tasked to eventually form a detailed evaluation system for the differential diagnosis of these two tumors,aid the differential diagnosis process and provide basis for further clinical treatment.[Methods]1.We collected 91 cases with clear pathological diagnosis and complete clinical data were collected from December 2008 to November 2019,there were 40 cases in ACC group and 51 cases in BCA group.Then we examined the differences between two tumors in their clinical data.2.We also observed the morphological parameters of the two groups of ACC and BCA and analyzed the differences;located the typical sites,made tissue chips,further performed CD117,Ki67,S100 and other immunohistochemical stainings,PASM,AB-PAS,and analyze the differences between the two groups.We select the cases in the last 4 years for Fluorescence in situ hybridization(FISH)detection of MYB-NFIB fusion gene and CTNNB1 mutation,and observe and analyze the differences between the two groups of cases.3.We continued to follow it up by observing the efficacy of each group,making comparative analysis of the difference between the clinical prognosis,and analyzing the factors affecting the prognosis of ACC.[Results]There is no significant difference in the age,sex,and tumor size between ACC and BCA patients.But the difference in the location of ACC and BCA is statistically significant.That is BCA occurs more frequently in the parotid gland and ACC is more common in small salivary gland.Statistical analysis showed that the main differences between ACC and BCA were as follows(The following results are statistically different):Optical microscope: ACC tumor has no envelope,87.50% of the marginal tumor nests are vertically aligned with the host tissue,90% can see a certain proportion of peritumoral retraction cleft(PRC)(median 40%),the largest diameter of the cystic cavity <0.6cm,the cyst cavity/gland cavity is mostly blue stained mucus sample;BCA generally has an envelope,no obvious PRC is seen under the microscope,and the gland cavity is mostly powder stained collagen sample.Immunohistochemistry: ACC generally Ki67>5%,tumor cell nuclei β-catenin,LEF-1 negative,interstitial does not express S100;while BCA Ki67 index is low(<3%),some tumor cell nuclei β-catenin,LEF-1 is positive,and tumor stromal S100 is positive.CD117,P63,CK19,similar expression in these two tumors.Special staining: PASM staining can clearly show the basement membrane(BM)surrounding the tumor nest.The ACC tumor nest is separated from the surrounding BM and partially broken,while the BCA BM is closely connected with the tumor cells,showing a complete line.Molecular genetics: MYB-NFIB fusion gene was detected in 8 of 14 ACC(57.14%),CTNNB1 gene amplification occurred in 2 ACCs,and no amplification or deletion of MYB-NFIB fusion gene and CTNNB1 gene occurred in BCA group.51 cases of BCA were followed up for 3 to 134 months without recurrence or metastasis;One of the 40 patients with ACC was lost to follow-up,and the remaining 39 patients were followed up for 3 to 114 months.There were 20 patients died of tumor,5 patients had recurrence or metastasis,and 14 patients survived without tumor.The 5-year and 8-year survival rates of ACC were77.8% and 26.4%.The 2-year postoperative tumor-free survival rate was78.5%,and the 5-and 8-year tumor-free survival rates were 40.8% and 0.Multivariate COX regression analysis showed that age,histological grade,tumor necrosis,and nerve invasion were independent factors affecting the prognosis of ACC.[Conclusions]Light microscopy: the envelope of the tumor,the relationship between themarginal tumor nest and the host tissue,and the proportion of PRC in the tumor have a certain value in identifying ACC and BCA;in addition,the size of the cyst cavity/gland cavity and the content of the cavity are important for ACC and BCA Identification has a certain reminder effect.Immunohistochemistry: ACCKi67 is generally ≥ 5%,β-catenin and LEF-1 of tumor cell nucleus are not expressed,and interstitial does not express S100;while Ki67 of BCA is low(<3%),some tumor cell nucleus β-catenin,LEF-1 was positive,and tumor stromal S100 was positive.2.Immunohistochemistry: Ki67,β-catenin,LEF-1,and S100 have higher significance in the differential diagnosis of ACC and BCA,but CD117,P63,and CK19 have little significance in the differentiation of the two.3.Special staining: PASM staining can clearly show the BM situation around the tumor nest,and has a high application value in distinguishing ACC and BCA.4.Molecular pathology: MYB-NFIB fusion gene(57.14%)can appear in ACC,while BCA is negative.5.The prognosis of ACC and BCA is completely different.There is no recurrence and metastasis after BCA.The 8-year survival rate after ACC is26.4%,and the 5-year tumor-free survival rate is 40.8%;age,histological grade,necrosis and nerve Invasion is an independent factor that affects the prognosis of ACC. |
