Abstract: Objective: To explore the clinicopathologic features of primary subungual malignant melanoma. Methods: The clinicopathologic and prognostic information of 28 cases of subnail malignant melanoma in our hospital from January 2013 to June 2022 were analyzed respectively. Results: Of 28 cases, 12 were male and 16 were female, the average age was 50 years old, and the lesions most occurred on the thumb, with clinical manifestations such as black line of the nail, nail destruction, etc. The width of the black line was greater than 3 mm, and 9 cases were positive for Hutchinson. The histological type was mainly of the limb freckle-like nevus type, and the cellular composition was mainly of epithelioid cells. The positivity rate of immunohistochemistry was higher in the expression of SOX10 than that of S100. Sixteen cases were followed up, including 7 cases were treated with extended resection, eight with local amputation, and one died after chemotherapy, and 12 cases were lost to follow up. Conclusion: Subungual malignant melanoma has different clinicopathologic characteristics from malignant melanoma in other parts of the body, and is easy to be misdiagnosed both clinically and pathologically. For patients who are older than 50 years old, with clinical manifestations of black nail lines, width >3mm, and Hutchinson's positivity should be alerted to subnail malignant melanoma, and pathological examination should be done in time.

Key words: nail')">">nail, malignant melanoma, clinicopathologic analysis