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

Abstract

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.

Keywords: Touton cells; foamy histiocytes; histopathology; line-field confocal optical coherence tomography; xanthogranuloma.

FIGURE 1

Xanthogranuloma. A, Clinical presentation. B, Polarized dermoscopy (×10) showing yellowish clods on an orange‐yellowish background

FIGURE 2

Line‐field confocal optical coherence tomography (LC‐OCT) examination of the central portion of the lesion. Vertical (A, field of view: 1200 × 250 μm) and horizontal (B, field of view: 1200 × 500 μm) sections showing enlarged dermal papillae (DP) containing roundish bright giant cells (yellow arrows) and giant cells showing a dark center surrounded by a highly hyper‐refractile peripheral ring (green arrows). The white squares indicate the same giant cell, measuring about 50 μm, located at the intersection of vertical and horizontal sections. The blue line in A corresponds to the level of the horizontal cut shown in B. The red line in B corresponds to the level of vertical cut shown in A. Insert: Dermoscopy of the examined lesion; the blue rectangle corresponds to the area shown in B (field of view: 1200 × 500 μm)

FIGURE 3

A, Line‐field confocal optical coherence tomography (LC‐OCT) vertical section showing a normal epidermis (EP), and enlarged dermal papillae (DP) appearing as darker areas containing roundish bright giant cells (yellow arrows) and giant cells showing a dark center surrounded by a highly hyper‐refractile peripheral ring (green arrows). B, Corresponding vertical histopathology section showing a dense inflammatory infiltrate of the superficial and mid dermis, mainly composed of foamy histiocytes (yellow arrow) with scattered Touton giant cells (green arrow) (H&E, original magnification ×200)

FIGURE 4

A, Line‐field confocal optical coherence tomography (LC‐OCT) horizontal section showing enlarged dermal papillae (DP) appearing as roundish areas separated by thin septa and containing roundish bright giant cells (yellow arrows), and giant cells showing a dark center surrounded by a highly hyper‐refractile peripheral ring (green arrows). B, Corresponding horizontal histopathology section at the dermoepidermal junction level revealing the presence of enlarged dermal papillae filled with multiple foamy histiocytes (yellow arrow) and Touton giant cells (green arrow), and surrounded by thinned rete ridges (H&E, original magnification ×200)