In vivo detection of mucosal healing-involved histiocytes by confocal laser endomicroscopy

Figure 1 Endoscopic and endomicroscopic characterization of the sigmoid colon in the context of a post-infectious mucosal healing process. A: White light colonoscopy shows mild atrophy and reduced vascular pattern in the sigmoid colon; B: Fluorescence-guided confocal laser endomicroscopy reveals large polyclonal cells (red arrowheads) with copious cytoplasm in the lamina propria - near two crypts (Cr) - corresponding morphologically to foamy histiocytes; C: In an enlarged manner the aggregated histiocytes with large fluorescence-negative nuclei (yellow arrowheads) and foamy cytoplasm (blue arrowheads) defining their appearance and nomenclature.

Figure 2 Histopathologic confirmation of the endomicroscopic findings. A-C: Large polyclonal histiocytes between mucosal crypts (arrows) are highlighted in the hematoxylin-eosin stain (A) as well as in Periodic acid-Schiff stain after diastase predigestion (B) and image (C) (CD68 immunostaining) with a CD68-positive cytosol, overall confirming the endomicroscopical findings.