 The investigators will use an advanced high resolution 3D optical coherence tomography OCT technology to observe skin tissue images in ex vivo culture. Parts of melanoma or benign pigmented lesions specimens derived from biopsy or surgical excision specimen will be observed by 3D optical tomography. A tiny tissue fragment of melanoma or benign pigmented lesions will be taken from surgical specimen without interference normal pathological evaluation. The location of melanocytic cells in melanoma or benign tissue fragments will be mapped by the 3D optical coherence tomography OCT. The 3D optic tomography system utilize a Ce:YAG optical fiber as light source and also combined with confocal microscopy. Taken together, these features made the 3D optic tomography system have very high resolution and suitable for single cell imaging. This study will not interfere with the normal medical practice and had no impact on patients safety and health. All of the materials will be destroyed once the experiments are done. The enrollment criteria will be dermatological patients who need to surgical intervention. 