Objective To study the clinicopathological characteristics and diagnosis of hepatic perivascular epithelioid cell tumour (PEComa).Methods Retrospective analysis was made on the clinicopathological and immunohistochemical phenotype of the 9 PEComa cases.Results The average age was 39 years,male to female ratio was 1∶ 8.Tumours were grossly well-circumscribed and solid.The maximum diameter were from 1.0 cm to 9.0 cm,with the average of 3.6 cm.The tomours were of nested architecture and composed of uniform epithelioid cells with clear cytoplasm and round nuclei.A subset of tumours was dominated by spindle cells.Thick-wall blood vessels and fat cells were common.Tumour cells were positive for HMB45,MelanA,and SMA (8/8,7/7,4/4).Some of them were positive for S-100 (4/ 8).All of the 9 cases were negitive for hepatocyte (0/9).Ki-67 index of the tumours were below 10％ (9/ 9).All 9 cases were followed up from 3 months to 6 years,all were alive and recurrence free.Conclusion Hepatic PEComa is often seen in adult women with some specific histological patterns and immunophenotypes.Definite diagnosis of PEComa can be made by combining clinicopathological characteristics with a panel of immunohistochemical marks.PEComas grow slowly,often responds to surgical resection and rarely recur.

Objective:To study the clinical and pathologic factors of papillary thyroid microcarcinoma (PTMC) and its significance as a histopathologic subtype of papillary thyroid carcinoma (PTC).Methods:A retrospective study of 719 patients with non-high-risk PTMC who underwent surgery for the first time in the Peking University People′s Hospital from January 2007 to June 2019 was conducted, the relationship between clinicopathologic factors and lymph node metastasis, and the expression of four tumor markers CK19, HMBE1, Galectin-3 and CD56 by immunohistochemistry were evaluated. Some comparisons were made with PTC.Results:The peak patients′ age was 40-49 years for both non-high-risk PTMC and PTC; the lymph node metastasis rate was higher in the 30-39 years age group than the 50-59 years age group ( P<0.05); the lymph nodes metastasis rate was significantly higher for multiple lesions than for single lesion ( P<0.05). Lymph node metastasis rate of PTMC with capsular invasion was significantly higher than those without ( P<0.05). There was no significant correlation between lymph node metastasis of PTMC and patients′ gender, tumor location, tumor size, and lymphocytic thyroiditis. The expression rates of CK19, HMBE1 and Galectin-3 both in PTMC and PTC were 100%, and the expression rates of CD56 were 25.6% (85/332) and 20.0% (70/350) respectively. Conclusion:As the main pathologic subtype of PTC, a variety of clinicopathologic factors of PTMC are related to lymph node metastasis, and it is highly recommended to pay close attention to PTMC. The expression of tumor marker CD56 alone cannot be used as a basis to exclude PTMC and PTC.

Objectives: To study the significance of SATB2 expression in colon adenocarcinoma and its differential diagnosis function for ovarian metastatic adenocarcinoma. Methods: Immunohistochemistry was used to detect the expression level of SATB2 in 130 cases of colon adenocarcinoma. The relationship between the positive rate of SATB2 expression in colon cancer and clinicopathological factors was studied. Forty-seven cases of pancreatic ductal adenocarcinoma, 22 cases of cholangiocarcinoma, 46 cases of gastric adenocarcinoma, and 53 cases of ovarian mucinous adenocarcinoma were studied respectively. Results: The positive expression rate of SATB2 in 130 cases of colon adenocarcinoma is 73.8%. The SATB2 expression bears no correlation with gender, age, tumor size, location, histology type, lymph node metastasis, staging, local recurrence, distant metastasis, survival, Kras mutation, and microsatellite stability. The expression rate of SATB2 is significantly higher in well differentiated and moderately differentiated colon adenocarcinoma than that in poorly differentiated adenocarcinoma (χ²=12.804, P=0.002); the expression rate in the cases without tumor deposit is significantly higher than in cases with tumor deposit (χ²=6.485, P=0.011). There was no positive expression in all cases of pancreatic adenocarcinoma, cholangiocarcinoma, gastric adenocarcinoma, nor in ovarian mucinous adenocarcinoma. Conclusion The expression of SATB2 is associated with the differentiation of colon adenocarcinoma and the formation of tumor deposit. SATB2 can be used as an effective tumor marker for identifying colorectal cancer ovarian metastases.

Objective: To investigate the expression of immunomarkers CK7, CK20, CK17, CDX2, MUC1 and MUC2 in primary adenocarcinoma of the ampulla of Vater, to explore the role of these markers in the histopathologic subclassification of ampullary carcinoma; and to provide biologic basis for precision treatment of patients with different types of ampullary carcinoma. Methods: Forty-two cases of primary ampullary carcinoma were collected at Peking University People′s Hospital, from 2012 to 2018 year. There were 22 males and 20 females. Aged range 42 to 88 years old, with mean aged (62±11) years. Among the patients, 6 was high differentiation, 19 median differentiation, and 17 low differentiation. Immunohistochemical studies on the expression of CK7, CK20, CK17, CDX2, MUC1 and MUC2 were performed in 42 cases of primary ampullary carcinoma. The relationship between different ampullary carcinoma subtypes and clinicopathologic survival data was analyzed using SPSS 16.0 statistical software. Results: Three histopathologic subtypes were observed. Among 42 cases, 8(19.0%)were classified as intestinal subtype, which showed a positive expression rate of 8/8 for both CK20 and CDX2, and 5/8 for MUC2. Both CK7 and CK17 were weakly expressed in one case (1/8). No expression was observed for MUC1 in this subtype. Twenty-two (52.4%,22/42) cases were classified as pancreaticobiliary subtype, which showed a positive expression rate of 100.0%(22/22) for both CK7 and MUC1, and 90.9% (20/22) for CK17. No expression was observed for CK20, CDX2 and MUC2.The remaining 12 (28.6%) cases were classified as mixed subtype, which showed variable expression patterns. The expression frequencies of these 6 immunomarkers in different subtypes of ampullary carcinoma did not correlate with various clinicopathologic factors such as patient gender and age, tumor size, histologic differentiation, pancreatic and bile duct invasion, or the depth of duodenal invasion. However, stage Ⅲ+Ⅳ diseases were more commonly seen in pancreaticobiliary type (63.6%,14/22) than intestinal type (2/8) and mixed type (3/9; χ²=6.508, P=0.039). Follow-up data showed a trend of better survival rate for patients with intestinal subtype than those with mixed and pancreaticobiliary subtypes. Conclusions Ampullary carcinoma can be subclassified into three different subtypes using a panel of six immunomarkers, especially for the identification of subtypes of poorly differentiated carcinoma. CK7, CK17 and MUC1 are major markers of pancreaticobiliary subtype, whereas CK20, CDX2 and MUC2 are useful markers for intestinal subtype. The mixed subtype variably expresses these markers. The prognosis of patients with intestinal subtype appears better than that of pancreaticobiliary and mixed subtypes. Accurate subtyping of ampullary carcinoma is clinically important to patient management and prognosis assessment.