[Clinicopathologic analysis of micro and mini parotid gland tumors].

OBJECTIVE: To investigate the clinicopathological characteristics of micro and mini parotid gland tumors and to provide reference for their clinical diagnosis and treatment. METHODS: Patients with parotid gland tumors treated in the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from December 2012 to April 2020 were selected. Relevant clinical data of the patients with tumor diameter ≤20 mm detected by preoperative CT were collected to analyze the clinicopathological characteristics and prognosis of micro and mini parotid gland tumors. And the collected data were divided into two groups with diameter 11-20 mm and diameter ≤10 mm according to tumor diameter measured by preoperative CT. The clinicopathological differences between the two groups were statistically analyzed. RESULTS: A total of 2 067 patients with primary epithelial parotid gland tumors were collected, and 685 patients with tumor diameter ≤20 mm were examined by CT, accounting for 33.1%. The ratio of male to female patients with micro and mini parotid gland tumors was 1 ∶1.93, the average age was (45.3±13.8) years (12-83 years), and the median course of disease was 12 months (1 week to 30 years). Among them, 635 cases (92.7%) were benign tumors, 50 cases (7.3%) were malignant tumors, and the ratio of benign to malignant was 12.7 ∶1. The most common benign tumor was pleomorphic adenoma, and the most common malignant tumor was mucoepidermoid carcinoma. The micro and mini parotid gland tumors were divided into 11-20 mm group (n=611) and ≤10 mm group (n=74), the clinical characteristics comparison of the two groups of gender ratio, average age, course of di-sease had no statistical difference (P>0.05). In the 11-20 mm diameter group, the percentage of benign and malignant tumor was 92.8% (567/611) and 7.2% (44/611) respectively, and the ratio of benign to malignant tumors was 12.9 ∶1. In the ≤10 mm diameter group, the percentage of benign and malignant tumor was 91.9% (68/74) and 8.1% (6/74) respectively, and the ratio of benign to malignant tumors was 11.3 ∶1. There was no significant difference between the two groups (P>0.05). Fifty patients with malignant tumor were followed up for the median follow-up period of 39.5 months (1-91 months). Local recurrence occurred in 2 patients with one death. The overall 2-year survival rate was 93.7% and the 5-year survival rate was 89.3%. CONCLUSION: The majority of micro and mini parotid gland tumors was benign lesion. There was a good prognosis for micro and mini parotid gland carcinoma. Early surgical treatment was recommended for micro and mini parotid gland tumors.

[Application of mixed reality technique for the surgery of oral and maxillofacial tumors].

OBJECTIVE: To explore the application of mixed reality technique for the surgery of oral and maxillofacial tumors. METHODS: In this study, patients with a diagnosis of an oral and maxillofacial tumor who were referred to Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from December 2018 to January 2020 were selected. The preoperative contrast-enhanced computed tomography data of the patients were imported into StarAtlas Holographic Medical Imaging System (Visual 3D Corp., Beijing, China). Three-dimensional (3D) model of tumor and key structures, such as skeleton and vessels were reconstructed to three-dimensionally present the spatial relationship between them, followed with the key structures delineation and preoperative virtual surgical planning. By using mixed reality technique, the real-time 3D model was displayed stereotactically in the surgical site. While keeping sterile during operation, the surgeon could use simple gestures to adjust the 3D model, and observed the location, range, and size of tumor and the key structures adjacent to the tumor. Mixed reality technique was used to assist the operation: 3D model registration was performed for guidance before tumor excision; intraoperative real-time verification was performed during tumor exposure and after excision of the tumor. The Likert scale was used to evaluate the application of mixed reality technique after the operation. RESULTS: Eight patients underwent mixed reality assisted tumor resection, and all of them successfully completed the operation. The average time of the 3D model registration was 12.0 minutes. In all the cases, the surgeon could intuitively and three-dimensionally observe the 3D model of the tumor and the surrounding anatomical structures, and could adjust the model during the operation. The results of the Likert scale showed that mixed reality technique got high scores in terms of perceptual accuracy, helping to locate the anatomical parts, the role of model guidance during surgery, and the potential for improving surgical safety (4.22, 4.19, 4.16, and 4.28 points respectively). Eight patients healed well without perioperative complications. CONCLUSION: By providing real-time stereotactic visualization of anatomy of surgical site and guiding the operation process through 3D model, mixed reality technique could improve the accuracy and safety of the excision of oral and maxillofacial tumors.

[An immunohistochemical study of CTHRC1,Vimentin,E-cadherin expression in papillary thyroid carcinoma].

Objective:To investigate the expression and significance of CTHRC1 in patients with papillary thyroid cancinoma.Method:We collected 63 specimens of papillary thyroid carcinoma tissue with 36 specimens of the adjacent normal thyroid tissue and 23 specimens of thyroid nodular goiter. The expressions of CTHRC1 protein in these tissues were detected by immunohistochemical staining. The correlations between the expressions of CTHRC1 with clinicopathologic features,E-cadherin and Vimentin expression were analyzed.Result:CTHRC1 protein expression levels in papillary thyroid carcinoma tissue were significantly higher than those in adjacent normal thyroid tissue and benign disease(P<0.01);CTHRC1 expression was significantly correlated with lymph node metastases(P<0.05). Moreover,CTHRC1 expression was correlated with the expression of E-cadherin and Vimentin(P<0.01).Conclusion:CTHRC1 is related with the occurrence and miligant transformation of papillary thyroid cancinoma. We speculated that CTHRC1 might play a role in the epithelial-mesenchymal transition of papillary thyroid cancinoma.

[Application of carbon nanoparticle in neck â ¥ lymph node dissection for papillary thyroid carcinoma].

Objective:To investigate the application value of carbon nanoparticle lymph tracer in Ⅵ lymph node dissection for papillary thyroid cancer.Method:One hundred and forty-eight patients with papillary thyroid cancer from October 2015 to May 2016 were enrolled into the retrospective analysis. Seventy-five cases with carbon nanoparticle injected in operation were divided into observation group, while the other seventy-three cases without lymph tracer were divided into control group. The number of neck Ⅵ lymph nodes and metastatic lymph nodes between the two groups were compared, as well as the incidence of parathyroid injury and postoperative hypocalcemia. Result:There were no significant difference in age, gender, tumor size, pathology or type of operation between the two groups(P>0.05). Parathyroid injury incidence in the observation group significantly lower than the control group (5.33% vs 5.33%, P< 0.05). There was significant difference in the number of neck Ⅵ lymph node dissection between the two groups (observation group: 6.51±4.65, control group: 4.42±3.10, P< 0.05).Conclusion:Carbon nanoparticle injected as a lymph tracer in thyroid surgery is helpful, the characteristics of the parathyroid gland negative imaging can effectively decrease the rate of parathyroid gland injury.