Immunohistochemical Study on Acral Lentiginous Melanoma / 대한피부과학회지

ABSTRACT

BACKGROUND: Although clinicopathologic characteristics of acral lentiginous melanoma (ALM) is well established, immunohistochemical study on ALM has rarely been reported. OBJECTIVE: Our purpose is to evaluate the usefulness of several immune markers in the diagnosis of ALM. METHODS: An immunohistochemical study was performed on paraffin sections of 20 ALMs using S-100 protein, HMB-45, vimentin, epithelial membrane antigen (EMA), and CAM 5.2. RESULTS: 1. Nineteen (95%) and 16 (80%) out of 20 ALM showed reactivity with S-100 protein and HMB-45, respectively. 2. Melanin bleaching was useful for diagnosing heavily pigmented ALM using both S-100 protein and HMB-45. 3. The immunoreactivity of S-100 protein and HMB-45 did not correlate with tumor thickness or level of invasion of ALM. The intensity of HMB-45 correlated well with the melanin content. 4. One and 2 out of 20 cases stained focally with EMA and CAM5.2 respectively, but these cases stained also with HMB-45 and/or S-100 protein. CONCLUSION: S-100 protein and HMB-45 were relatively sensitive markers for diagnosing ALM. Despite the occasional positivity for the epithelial markers in ALM, all epithelial marker-positive cases stained also with HMB-45 and/or S-100 protein. Therefore, S-100 protein and HMB-45 are very useful markers for diagnosing ALM.