Line-field confocal optical coherence tomography of xanthogranuloma: Correlation with vertical and horizontal histopathology.

Line-field confocal optical coherence tomography (LC-OCT) is a new noninvasive technique for a real-time, vertical, and horizontal imaging of the skin at cellular resolution. A 47-year-old female presented with a 6-month history of an asymptomatic yellowish papule. LC-OCT evaluation was able to show the diagnostic microscopic features of xanthogranuloma and showed an excellent correlation with vertical and horizontal histopathological sections by revealing enlarged dermal papillae containing multiple, bright roundish giant cells, corresponding to foamy histiocytes, and giant cells characterized by a dark center surrounded by a highly hyper-refractile peripheral ring, corresponding to Touton cells. LC-OCT may represent a valid, noninvasive alternative to histopathological examination in clinically atypical cases of xanthogranuloma.