[Merkel cell carcinoma: a clinicopathological study of 10 cases].

Objective: To investigate the clinicopathological features, differential diagnosis and prognosis of Merkel cell carcinoma (MCC). Methods: The clinical and pathological data of 10 patients with MCC were collected at the 940th Hospital of PLA. The histological characteristics were examined. Immunohistochemical EnVision method was used to detect thyroid transcription factor-1 (TTF1), broad-spectrum cytokeratin (CKpan), CK20, S-100, Ki-67, CD56, chromogranin A, synaptophysin and other markers in the 10 cases. Results: Intradermal MCC of the skin showed a nested, cord-like, cribriform distribution, polygonal cells, uniform size, and lack of cytoplasm. Tumor cell nuclei were large and round, with clear nuclear membranes, fine and scattered chromatin, absence of nucleoli, and mitotic figures of 10 per 50 high power fields. Among them, one patient had sarcoma and squamous cell carcinoma in situ, one patient had squamous cell carcinoma in situ, and one patient had unique cell morphology. Immunohistochemical staining showed that all cancer cells expressed CKpan, synaptophysin and CD56. There were seven cases with perinuclear dot-like positivity of CK20. Six MCCs expressed chromogranin A to varying degrees, while 2 MCCs were weakly positive for p63. The nuclear positive index in the Ki-67 hotspot area was 60%. Conclusion: The histology of MCC varies. Rendering a correct diagnosis of MCC requires adequate sampling, close correlation with clinical history and rational use of immunohistochemical staining. The treatment requires standardized surgery, postoperative radiotherapy and multimodal chemotherapy. Immunotherapy may replace the traditional treatment in the future.

[Investigation of epidemiological characteristics and influencing factors on dust-exposed working age of pneumoconiosis cases in a city].

Objective: To investigate epidemiological characteristics and influencing factors on dust-exposed working years of pneumoconiosis cases in Yantai. Methods: In January 2020, By Cluster sampling way, Using descriptive statistics to analyze dust-exposed working years of the reported 3307 new cases of pneumoconiosis from 2009 to 2019 in Yantai. Analyzing the variation trends by the chi-square trend test. Analyzing single fator by chi-square test. Using multiple classification Logistic Regression analysis to analyze multiple influencing factors. Results: The dust-exposed working age of pneumoconiosis cases decreased by years (P<0.05) . The starting age of dust exposure of cases increased year by year, while positively correlated with the dust-exposed working age (r=-0.217, P<0.05) . The years of dust exposure, starting age of dust exposure, industry, type of economy and scale of enterprise were main influence factors on the dust-exposed working age of pneumoconiosis cases. Conclusion: We should strengthen the management on prevention and control condition of pneumoconiosis in metal smelting and processing industry and privately-owned, small and micro enterprises, and pay attention to workers starting exposed to dust in the age of ≥28 years old.