Clinicopathological features of cutaneous malignant melanoma

Background: Malignant melanoma is the leading cause of death among skin cancers in western countries. The incidence of melanoma has been steadily increasing over the last 20 years, and age and sex distribution, anatomic location, clinicopathologic subtypes, and prognostic factors of malignant melanoma are also well known. However, various clinicopathologic aspects such as incidence, clinicopathologic subtypes and tumor behaviors are quite different in Asian and black skin. Objective: The purpose of this study was to investigate the clinicopathologic behavior and statistics of malignant melanoma patients of Kyungpook National University Hospital, and to evaluate prognostic predictors. Methods: Of the 97 out of 103 patients diagnosed with malignant melanoma at the Department of Dermatology of Kyungpook National University Hospital over a 14 year period (1992-2006), we analyzed mean age of onset, gender, rumor location, duration, tumor number, color, tumor thickness, dark's level, pathologic ulceration, tumorinfiltration lymphocytes, clinicopathologic subtype, and clinical AJCC stage. Univariate analysis and multivariate analyses for survival, according to clinical and histologie tumor settings, were performed by means of the Cox proportional hazard model. Survival curves were plotted by the Kaplan-Meier method. Results: Ninety-seven melanomas were identified and analyzed by both clinical behavior and pathology. Of these, 44 were male and 53 were female patients and the mean age was 59.7 years. Most of the tumors were located on the hands and feet. Thin melanoma was the most common tumor and histologic ulcerations were observed in 37 out of 81 patients who were available for evaluation. For tumor-infiltrating lymphocytes (TIL), 22 out of 76 patients were confirmed with TIL in the pathologic review. Acral lentiginous melanoma was the most common type, followed by nodular melanoma, superficial spreading melanoma, and lentigo maligna melanoma. Univariate analysis for overall survival of melanoma revealed that thickness of tumor, the presence of ulceration, the presence of tumor-infiltrating lymphocytes, clinicopathological subtype, and clinical stage have a tendency for a poorer prognosis. Multivariate analysis demonstrated that advanced stages (III and IV) and tumor thickness were the independent risk factors for poor prognosis. Conclusion: Few similar large studies have been conducted to assess the prognostic factors of melanoma in Korea. Therefore, further prospective studies are needed to assess the biological behavior of malignant melanoma, of which the incidence has been steadily increasing in Korea.