title: Differentiating intratumoral melanocytes from Langerhans cells in nonmelanocytic pigmented skin tumors in vivo by label-free third-harmonic generation microscopy.
abstract: Morphology and distribution of melanocytes are critical imaging information for the diagnosis of melanocytic lesions. However, how to image intratumoral melanocytes noninvasively in pigmented skin tumors is seldom investigated. Third-harmonic generation (THG) is shown to be enhanced by melanin, whereas high accuracy has been demonstrated using THG microscopy for in vivo differential diagnosis of nonmelanocytic pigmented skin tumors. It is thus desirable to investigate if label-free THG microscopy was capable to in vivo identify intratumoral melanocytes. In this study, histopathological correlations of label-free THG images with the immunohistochemical images stained with human melanoma black (HMB)-45 and cluster of differentiation 1a (CD1a) were made. The correlation results indicated that the intratumoral THG-bright dendritic-cell-like signals were endogenously derived from melanocytes rather than Langerhans cells (LCs). The consistency between THG-bright dendritic-cell-like signals and HMB-45 melanocyte staining showed a kappa coefficient of 0.807, 84.6% sensitivity, and 95% specificity. In contrast, a kappa coefficient of −0.37, 21.7% sensitivity, and 30% specificity were noted between the THG-bright dendritic-cell-like signals and CD1a staining for LCs. Our study indicates the capability of noninvasive label-free THG microscopy to differentiate intratumoral melanocytes from LCs, which is not feasible in previous in vivo label-free clinical-imaging modalities.
authors.affiliation: National Taiwan University, Molecular Imaging Center, No. 1, Section 4, Roosevelt Road, Da'an District, Taipei 10617, TaiwanbHarvard Medical School, Department of Biomedical Informatics, 10 Shattuck Street, Boston, Massachusetts 02115, United States.
authors.forename: Wei-Hung
authors.initials: WH
authors.lastname: Weng
authors.affiliation: National Taiwan University, Molecular Imaging Center, No. 1, Section 4, Roosevelt Road, Da'an District, Taipei 10617, TaiwancNational Taiwan University Hospital and National Taiwan University College of Medicine, Department of Dermatology, No. 7, Zhongsha.
authors.forename: Yi-Hua
authors.initials: YH
authors.lastname: Liao
authors.affiliation: National Taiwan University, Molecular Imaging Center, No. 1, Section 4, Roosevelt Road, Da'an District, Taipei 10617, Taiwan.
authors.forename: Ming-Rung
authors.initials: MR
authors.lastname: Tsai
authors.affiliation: National Taiwan University, Molecular Imaging Center, No. 1, Section 4, Roosevelt Road, Da'an District, Taipei 10617, Taiwan.
authors.forename: Ming-Liang
authors.initials: ML
authors.lastname: Wei
authors.affiliation: National Taiwan University Hospital and National Taiwan University College of Medicine, Department of Pathology, No. 7, Zhongshan S Road, Zhongzheng District, Taipei 100, Taiwan.
authors.forename: Hsin-Yi
authors.initials: HY
authors.lastname: Huang
authors.affiliation: National Taiwan University, Molecular Imaging Center, No. 1, Section 4, Roosevelt Road, Da'an District, Taipei 10617, TaiwaneNational Taiwan University, Department of Electrical Engineering and Graduate Institute of Photonics and Optoelectronics, No. 1, S.
authors.forename: Chi-Kuang
authors.initials: CK
authors.lastname: Sun
mesh_terms: D003952:Diagnostic Imaging / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D007801:Langerhans Cells / Q000166:cytology*; D008544:Melanocytes / Q000166:cytology*; D008853:Microscopy; D012878:Skin Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology