The Clinical Characteristics Of Patients With Sellar Germ Cell Tumor And Preliminary Exploration Of The Gene Expression Of Cerebrospinal Fluid Leukocyte Tumors In Sellar Disease

Part 1 Clinical characteristics summary of patients with germinomas in sellarObjective:Patients with central diabetes insipidus often have pituitary stalk thickening(PST)on imaging and the etiological identification of PST is challenging.This study summarized the clinicopathological features of patients with germinomas in sellar.Methods:To retrospectively analyze the clinical characteristics of germinomas patients with PST,admitted to Peking Union Medical Hospital from January 2008 to October 2018 and to involve langerhans cell histiocytosis(LCH)and autoimmune hypophysitis,AH)patients for comparison,providing clinical evidence for differential diagnosis.Results:A total of 85 cases of germinomas,65 cases of LCH,30 cases of AH patients were included,whose ratio of male to female is 0.7:1,1.5:1 and 0.5:1,respectively.The age of onset was AH>LCH>germinoma(38.7 years>20.1 years>12.0 years,P<0.001).The time interval between the onset and diagnosis of germinomas was longer than AH(2.0 vs 0.6 years,P=0.005).CDI was the most common primary chief complaint in three groups(66.7%?76.9%),the second common chief complaint of all groups was menstrual disorder.HPG axis was the most common type of pituitary function deficiency in all.The incidence of deficiency in HPA axis,HPT axis,HPG axis,GH-IGF1 axis and panhypopituitarism were highest in germinomas.The number of cerebrospinal fluid leukocytes(3*106/L vs 2*106/L)and monocytes(4*106/L vs 1*106/L)in germinomas were significantly higher than those in LCH(P<0.02),but lower glucose in germinomas compared with LCH(3.1mmol/L vs 3.3mmol/L,P=0.017)and AH(3.1mmol/L vs 3.3mmol/L,P=0.021).Cerebrospinal fluid and blood ?-HCG levels were significantly higher in germinomas than in LCH and AH(P<0.005).There was no significant difference in the transverse and anteroposterior diameter of pituitary stalk in three groups,with high ratio of invisible posterior pituitary bright spot in all groups(92.3%?100%).The cut-off cerebrospinal fluid ?-HCG of 4.9 mIU/ml had a sensitivity of 67.1%and a specificity of 75.0%for the presence of germinomas.The onset age was<20 years(OR=6.878,P<0.001),cerebrospinal fluid ?-HCG>4.9 mIU/ml(OR=8.325,P<0.001),panhypopituitarism(OR=6.954,P=0.005),cerebrospinal fluid glucose ?3.3mmol/L(OR=4.311,P=0.013)were risk factors of germinomas·Conclusions:Younger age of onset,panhypopituitarism,high level of cerebrospinal fluid ?-HCG,and low level of cerebrospinal fluid glucose are risk factors for germinomas.It is difficult to identify the etiology of PST by imaging examination.If necessary,biopsy should be considered to differetiate these causes apart.Part 2 Preliminary study on tumor gene expression of leukocytes in cerebrospinal fluid of saddle lesions.Objective:The tumor gene expressions of leukocytes in cerebrospinal fluid were detected by droplet digital PCR(ddPCR)and the differences in gene expression levels of several tumors in saddle were explored.Methods:CSF samples were collected from 14 cases of germinomas,4 cases of langerhans cell histiocytosis(LCH)and 3 cases of pituitary non-functioning adenomas patients,who were admitted at Peking Union Medical College Hospital from August 2018 to May 2019.Peripheral blood leukocytes of healthy people were used as control group.The results of CSF tests and clinical data were collected.One-step ddPCR was used for absolute quantification of eight germinoma-specific genes expression(PLAP?OCT3/4?SALL4?CD117?SOX9?NANOG?HCG?EMA)and eight LCH-specific genes expression(CD1a?S100?CD207?BRAF?CD40?CD45?CD68?CD163).The results were analyzed and compared between different diseases.The relationship between gene expression levels and leukocytes' numbers in CSF was explored.Results:The one-step ddPCR was recogniazed as a stable,reliable,highly repeatable method by detecting expression level of ?-actin in the high/low expression samples between batches.Both cerebrospinal fluid and peripheral blood leukocytes express specific genes for germinomas and LCH.For every tumor type,CD117 and SALL4 were not expressed or expressed at a low level,which were consistent with the expression of peripheral blood leukocytes in healthy people.Except for CD117 and SALL4,germinoma had the highest expressions of all markers among three groups with no statistical significance(P>0.05).There was a positive correlation between the number of leukocytes in the CSF and the median expression level of the 14 genes(rs=0.664,P=0.001).The expression levels of CD 1a,S100,CD207,BRAF,CD68,CD 163,PLAP,OCT3/4 and HCG were also positively correlated with the number of leukocytes in CSF(P<0.05).Conclusions:The stronger activation of the leukocytes in the cerebrospinal fluid was acquired in germinoma than the other two diseases.CD117 and SALL4 may be specific markers for germinoma in CSF.