One patient with gallbladder mass had transient jaundice and was diagnosed with gallbladder carcinoma by abdominal ultrasonography， contrast-enhanced CT， MRCP， and PET-CT. Surgical exploration showed enlarged gallbladder and a mass in the neck of the gallbladder pressing against the hilum of the liver， with no manifestation of tumor invasion， and there were no signs of liver metastasis. Only cholecystectomy was performed for the patient. The pathological diagnosis was tubular adenoma of the gallbladder without carcinogenesis. This case is characterized by a large gallbladder tumor， without marginal infiltration on imaging or malignant transformation based on pathology.

Purpose To investigate the clinical pathology of SMARCB1/INI1-deficient poorly differentiated chordoma.Methods Ten patients with poorly differentiated chordoma were collected.The expression of CK,vimentin,INI1,and Brachyu-ry was detected using EnVision immunohistochemistry.Clinical characteristics,histopathological features,as well as related prognosis were analyzed and the literature was reviewed.Results Among the 10 cases,including 5 males and 5 females,the mean age of onset was 4 years.10 cases were located in the cliv-us and had bone invasion,3 involved the cervical spine(18.2％).In morphology,tumor cells showed sheet or nest mass growth,with epithelioid tumor cells.The nucleus was round or oval,with obvious atypia and visible nucleoli.Mitotic figures were active.Lymphocytic infiltration was noted in the stroma.Tumor cells in 10 cases were positive for CK,Vimen-tin,EMA and Brachyury with loss of SMARCB1/INI1 expres-sion.Ten patients were followed-up postoperatively.5 patients had tumor recurrence(median progression-free survival was 4 months)and 7 died(median overall survival was 5 months).Conclusion SMARCB1/INI1-deficient poorly-differentiated chordoma is a relatively rare bone tumor with poor prognosis and challenging diagnosis.Understanding the clinical pathological characteristics of this tumor has great significance for diagnosis and treatment.

Objective:To examine whether immunohistochemistry of methylthioadenosine phosphorylase (MTAP) and p16 could be used to predict the CDKN2A status in various brain tumors.Methods:A total of 118 cases of IDH-mutant astrocytomas, 16 IDH-wildtype glioblastoma, 17 polymorphic xanthoastrocytoma (PXA) and 20 meningiomas diagnosed at Xuanwu Hospital, Capital Medical University, Beijing, China from November 2017 to October 2023 were collected and analyzed. The CDKN2A status was detected by using fluorescence in situ hybridization or next-generation sequencing. Expression of MTAP and p16 proteins was detected with immunohistochemistry. The association of loss of MTAP/p16 expression with CDKN2A homozygous/heterozygous deletion was examined.Results:Among the 118 cases of IDH-mutant astrocytoma, 13 cases showed homozygous deletion of CDKN2A. All of them had no expression of MTAP while 9 cases had no expression of p16. Among the 16 cases of IDH wild-type glioblastoma, 6 cases showed homozygous deletion of CDKN2A. All 6 cases had no expression of MTAP, while 3 of these cases had no expression of p16 expression. Among the 17 PXA cases, 4 cases showed homozygous deletion of CDKN2A, and the expression of MTAP and p16 was also absent in these 4 cases. Among the 20 cases of meningiomas, 4 cases showed homozygous deletion of CDKN2A. Their expression of MTAP and p16 was also absent. Among the four types of brain tumors, MTAP was significantly correlated with CDKN2A homozygous deletion ( P<0.05), with a sensitivity of 100%. However, it was only significantly correlated with the loss of heterozygosity (LOH) of CDKN2A in astrocytomas ( P<0.001). P16 was associated with CDKN2A homozygous deletion in IDH-mutant astrocytoma and PXA ( P<0.001), but not with the LOH of CDKN2A. Its sensitivity and specificity were lower than that of MTAP. Conclusions:MTAP could serve as a predictive surrogate for CDKN2A homozygous deletion in adult IDH-mutant astrocytoma, PXA, adult IDH-wildtype glioblastoma and meningioma. However, p16 could only be used in the first two tumor types, and its specificity and sensitivity are lower than that of MTAP.

Objective:To analyze the clinical features and mutation of myeloid differentiation factor 88 (MYD88) L265P in patients with diffuse large B-cell lymphoma (DLBCL) of central nervous system (CNS).Methods:The clinicopathological materials of 45 cases of DLBCL of CNS were retrospectively collected in Xuanwu Hospital, Capital Medical University from September 2014 to February 2017. The clinicopathological data were retrospectively analyzed, combined with immunohistochemistry, EB virus in situ hybridization, imaging and medical history. The mutation of MYD88 L265P gene was detected by pyrosequencing and its clinical significance was analyzed. Results:The age of the patients ranged from 42 to 82 years [(57.6±8.8) years], including 24 males and 21 females. Totally 93.3% (42/45) of the patients had supratentorial tumours, which were single or multiple. The cerebral hemisphere (31/45, 68.9%) was the most common involved site, and 21 cases (21/45, 46.7%) had multiple lesions. Histologically, DLBCL in the CNS showed diffuse infiltration of tumor tissue, some of which grew around blood vessels in a "sleeve" arrangement. CD 20 and CD 79a were diffusely and strongly positive. Thirty-nine cases (39/45, 86.7%) were non-germinal center B cell (non-GCB) subtype and 6 cases (6/45, 13.3%) were germinal center B cell (GCB) subtype. MYD88 L265P mutation was found in 64.4% (29/45) patients. There was statistically significant difference between non-GCB type (71.8%, 28/39) and GCB type DLBCL (1/6, P=0.017). Compared with the operation/biopsy group without chemotherapy, operation+chemotherapy, biopsy+chemotherapy, operation/biopsy+chemotherapy+stem cell transplantation can improve the survival and prognosis ( HR=0.05, 95% CI 0.01-0.33 , P=0.002; HR=0.04, 95% CI 0.01-0.36 , P=0.004; HR=0.01, 95% CI 0.00-0.17 , P=0.001; respectively). Conclusions:DLBCL of the CNS is aggressive tumor with poor prognosis, the clinical manifestations are complex and diverse, and the diagnosis is challenging. MYD88 L265P is a common and specific gene mutation in primary CNS lymphoma(PCNSL), which is of great significance in the diagnosis and treatment of lymphoma. The MYD88 L265P mutation was more frequently detected in non-GCB than GCB subtype. Chemotherapy can improve the survival rate of PCNSL patients. If chemotherapy achieves complete remission and autologous hematopoietic stem cell transplantation is performed, there may be a chance of long-term survival.

Objective:To analyze the clinicopathological and molecular features and prognostic implications of adult isocitrate dehydrogenase wild type (IDH-wt) diffuse gliomas.Methods:A total of 87 cases of adult IDH-wt diffuse gliomas from 2016 to 2020 in Xuanwu Hospital of Capital Medical University were retrospectively collected. The clinicopathological characteristics and prognosis were analyzed. Molecular characteristics were also analyzed using Sanger sequencing and next generation sequencing.Results:There were 53 males and 34 females, aged from 19 to 78 years (mean 53 years). Histopathologically, there were 63 (72.4%) glioblastomas, 16 (18.4%) anaplastic astrocytomas, six (6.9%) diffuse astrocytomas, and one (1.1%) each of anaplastic oligodendrocytoma, and anaplastic oligodendroglioma. Common molecular genetic changes in IDH-wt gliomas included TERT promoter mutation which was found in 60 cases (69.0%); MGMT promoter methylation in 43 cases (49.4%); EGFR mutation in 38 cases (43.7%); PTEN mutation in 35 cases (40.2%) and TP53 mutation in 32 cases (36.8%). In addition, PDGFRA mutation was detected in 17 cases (19.5%), CDK4 amplification in 15 cases (17.2%) and MDM2 amplification in 11 cases (12.6%). In IDH-wt diffuse gliomas, there was no significant difference in the overall survival between TERT promoter, EGFR, PTEN, TP53, PDGFRA, CDK4, MDM2 mutations and the wild-type, since these gene mutations could co-occur in any case ( P>0.05). Also there was no significant difference in the overall survival between the WHO grade Ⅱ/Ⅲ gliomas and glioblastoma patients with these gene mutations ( P>0.05). Conclusions:TERT promoter, EGFR, PTEN, TP53, PDGFRA, CDK4 and MDM2 gene mutations are common molecular genetic changes in adult IDH-wt gliomas, and are associated with poor prognosis. It is suggested that these genes are potentially useful for predicting the prognosis and should be tested in adult IDH-wt gliomas.

Objective:To analyze the clinicopathological features of chordoid glioma.Methods:A total of 12 cases of chordoid gliomas from 2009 to 2020 in Xuanwu Hospital of Capital Medical University and General Hospital of Chinese People′s Liberation Army were retrospectively analyzed. The clinical and imaging characteristics, pathologic and molecular characteristics were analyzed, and the relevant literature was reviewed.Results:All 12 patients (4 males and 8 females) aged from 25 to 67 years (mean 39 years) and mainly had a history of headache or/and vision loss. MRI showed that the lesions located in the third ventricle, and they showed abnormal enhancement. Pathologically, these 12 cases displayed the morphologic characteristics of chordoid gliomas, including papillary structures in two cases. Immunohistochemically, GFAP and vimentin were expressed in all 12 cases (12/12). TTF1 was also expressed in all cases (10/10). CD34 and CKpan were seen in 11 cases (11/12). EMA with dot-and/or-ring like positivity was seen in 9 cases (9/10). Tissues were available in nine chordoid gliomas for Sanger sequencing to detect PRKCA and IDH gene mutation, and eight cases (8/9) showed PRKCA gene D463H mutation. None of these cases showed IDH1 R132 and IDH2 R172 mutation. All 12 patients underwent surgery, and four were lost to follow up. The remaining eight patients were progression or recurrence free at last follow-up in January 2021.Conclusions:Chordoid gliomas have relatively distinguishing clinical and histopathological features. PRKCA gene mutation in chordoid gliomas can be considered as a biomarker for the diagnosis and differential diagnosis of chordoid gliomas, and may provide a direction for future targeted therapy.

Objective:To investigate the clinicopathological features, diagnosis and prognosis of diffuse leptomeningeal glioneuronal tumor (DLGNT).Methods:Five cases of DLGNT diagnosed from January 2016 to January 2020 were collected from Xuanwu Hospital, Capital Medical University. The clinical features, histopathologic characteristics, immunohistochemical and molecular genetic findings and prognosis were analyzed and the relevant literature was reviewed.Results:The five patients (two males and three females) were aged 2 to 52 years (median 11 years), and had history of increased intracranial pressure (headache and vomiting) or limb weakness. Three of them were younger than 16 years of age. The imaging studies showed diffuse intracranial and intraspinal nodular leptomeningeal thickening and enhancement, with or without parenchymal involvement. At times there were associated small cyst-like lesions. Imaging interpretations were inflammatory lesions in three cases and space occupying lesions in two. Microscopically, in three cases the tumors showed low to moderate cellularity, consisting of relatively monomorphous oligodendrocyte-like cells arranged in small nests or diffusely distribution. No mitosis and necrosis were observed. In two cases there were increased cellularity with a diffuse honeycomb pattern. The tumor showed mild to moderate polymorphism with hyperchromatic nuclei. Mitosis, endothelial vascular proliferation and glomeruloid vessels were seen. Necrosis was absent. The tumor cells in all five cases were positive for synaptophysin,Olig2 and negative for IDH1 and H3 K27M. GFAP was focally positive in four cases and only one case expressed NeuN partly. The Ki-67 labeling index was 1%-35%. BRAF fusion was detected in four cases. Genetic analysis showed solitary 1p deletion in two cases (2/5), while all cases were negative for 1p/19q co-deletion (0/5). The five patients were followed up for 13 to 28 months (median 15 month). One patient died after 27 months. There was no evidence of tumor progression in the remaining four patients.Conclusions:DLGNT is rare and easily confused with other central nervous system tumors and inflammatory lesions. Therefore, the diagnosis of DLGNT should be made based on comprehensive information including imaging, morphologic and corresponding immunohistochemical examinations and molecular genetics to avoid misdiagnosis and delay in management.

Objective:To investigate the clinicopathological features, immunophenotype, molecular genetics and prognosis of extraskeletal mesenchymal chondrosarcoma in central nerve system (CNS).Methods:The clinicopathological findings, immunohistochemistry and genetic analysis of four cases of extraskeletal mesenchymal chondrosarcoma in Xuanwu Hospital between 2014 and 2019 were reviewed and followed up.Results:The ages of patients ranged from 20-35 years. Three patients had intracranial lesions and one had intradural tumor. The characteristic histologic features were undifferentiated small cells together with scattered islands of hyaline cartilage. There was hemangiopericytoma-like pattern with calcification and ossification. The tumor cells were positive for VIM and SOX9; and the small cells were positive for CD99, NSE and NKX3.1. The cells in chondroid matrix were positive for S-100. All tumor cells were negative for markers including CKpan, EMA and desmin. At molecular analysis, HEY1-NCOA2 fusion transcripts were identified in three patients. The fusion points were between exon 4 of HEY1 and exon 13 of NCOA2 . Follow-up information was obtained in two patients, and both were free from recurrence or metastasis at 8 and 20 months. Conclusions:Extraskeletal mesenchymaI chondrosarcoma is a rare CNS disease with poor prognosis. In addition to SOX9, NKX3.1 can be another useful antibody for the differential diagnosis. The combination of pathological characteristics, immunophenotype and genetic profile of tumor is essential for diagnosis.

Objective:To investigate the clinicopathological and molecular genetic characteristics of tall cell variant and hobnail variant of papillary thyroid carcinoma (PTC).Methods:Twenty-one cases of tall cell variant (TCV-PTC) of PTC (TCV-PTC) and ten cases of hobnail variant of PTC (HV-PTC), as the highly aggressive group, were collected from Xuanwu Hospital from August 2009 to August 2015. Twenty-two cases of follicular variant and 21 classical PTC cases were included as control. Relevant clinical and pathologic data were obtained, and in some cases, paraffin samples were selected for gene mutation spectrum analysis using second generation sequencing.Results:There were 18 males and 56 females; 57 patients were younger than 55 years of age, and 17 patients were 55 years or older. The mean tumor size was 1.6 cm for the high-aggressive group (TCV-PTC and HV-PTC), 1.1 cm for the follicular subtype, and 1.6 cm for the classical type. There were 54 cases with thyroid capsule invasion, 24 cases with extra-thyroidal invasion, and 45 patients with lymph node metastases. Regional recurrence occurred in 7 cases, no recurrence in 54 cases, and 13 patients were lost to follow-up. The highly aggressive group was more likely to show extra-thyroidal invasion, lymph node metastases and recurrence than those with classical PTC ( P<0.05). Within this cohort, BRAF V600E mutation was detected in 53 cases and TERT promoter mutation in 6 cases. Compared with the single mutation group and no mutation group, BRAF and TERT promoter co-mutation group was more commonly detected in older age, male, larger tumor size and more prone to extra-thyroid invasion ( P<0.05). In addition, among BRAF and TERT co-mutation cases, the highly-aggressive group accounted for the highest proportion (5/6). Conclusions:TCV-PTC and HV-PTC, as highly-aggressive variants of PTC, show more aggressive biologic behavior (more lymph node metastasis, external thyroid invasion and recurrences) than the classical and follicular variants of PTC. Coexisting BRAF and TERT promoter mutations may be associated with invasive biologic behavior.

Objective: To summarize the clinicopathological features of cystic meningioangiomatosis. Methods: The clinical manifestations, imaging characteristics and pathological features of a case of cystic meningioangiomatosis were analysed, and the relevant literature was reviewed. Results: A 16-year-old male patient from Xuanwu Hospital, Capital Medical University had a history of epileptic seizures for more than three months. Magnetic resonance imaging (MRI) demonstrated a cystic mass in the left frontal lobe with long T₁ and long T₂ signals. Extensive resection of the upper frontal gyrus was performed. The excised lesion presented with a cystic shape after incision and contained colorless translucent liquid. Microscopic examination of the lesion showed that the number of blood vessels in the local cortex of the brain tissue was increased and the vessels appeared to be branching. The blood vessel walls were surrounded by proliferative spindle cells, which were arranged in concentric circles. Immunohistochemical study revealed that those spindle cells and the cyst wall were vimentin positive. These cells had a rich reticular fibers. Ten months after the operation, the general condition of the patient was good, no epileptic seiƶure was observed, and the follow-up MRI did not reveal any residual lesion. Conclusions MRI of cystic meningioangiomatosis shows cystic space occupying. Pathological findings show typical features of meningioangiomatosis and cystic space formation. Cystic meningioangiomatosis has good prognosis after surgical resection.