1. Inner gray halo, a novel dermoscopic feature for the diagnosis of pigmented actinic keratosis: Clues for the differential diagnosis with lentigo maligna 
Mauricio M. Nascimento, MD, Danielle Shitara, MD, Milvia M.S.S. Enokihara, MD, PhD, Sergio Yamada, MD, Giovanni Pellacani, MD, PhD, Gisele G. Rezze, MD, PhD 
Journal of the American Academy of Dermatology 
Volume 71, Issue 4, Pages (October 2014)
DOI: /j.jaad
Copyright © 2014 American Academy of Dermatology, Inc. Terms and Conditions

2. Fig 1
Pigmented actinic keratoses (PAK) and lentigo maligna (LM). Dermoscopic aspects. A, PAK showing rhomboidal structures (asterisk) and inner gray halo (IGH) (yellow arrows). B, PAK with IGH. C, LM depicting IGH, rhomboidal structures, asymmetric pigmented follicular openings (arrowheads), and annular-granular pattern (black arrows). D, PAK showing rhomboidal structures, IGH, and annular-granular pattern.
Journal of the American Academy of Dermatology  , DOI: ( /j.jaad )
Copyright © 2014 American Academy of Dermatology, Inc. Terms and Conditions

3. Fig 2
Pigmented actinic keratosis (PAK). Dermoscopic image and schematic drawing of inner gray halo (IGH). A, Transverse (en face) drawing section of IGH: keratotic plug seen on dermoscopy (yellow); pseudonetwork (brown) and IGH (hatched gray). B, Dermoscopic image of PAK, showing multiple IGH. C, Magnified dermoscopic detail of IGH. D, Magnified image of IGH with superimposed matching IGH drawing, showing keratotic plug (yellow asterisk), IGH, and pseudonetwork (black arrow).
Journal of the American Academy of Dermatology  , DOI: ( /j.jaad )
Copyright © 2014 American Academy of Dermatology, Inc. Terms and Conditions

4. Fig 3
Pigmented actinic keratosis (PAK). Dermoscopic-histologic correlation of inner gray halo (IGH). A, Schematic drawing of PAK. Dermoscopic feature keratotic plug (yellow). Inverted cone of spared epidermis around the follicle (gray), which is the histologic counterpart of IGH; and pigmented anaplastic epidermis (actinic keratosis) (brown), which is the histologic correspondent of the pseudonetwork (adapted from Pinkus,15 © 1958 American Society of Clinical Pathologists). B1 and B2, Histologic demonstration of actinic damage sparing the umbrella-shaped follicular area of the same follicle shown in Fig 4, A-D. C, Transverse section showing no immunoexpression. D, Immunoexpression of epidermal keratinocytes. E, Perpendicular section showing melanin increase in basal keratinocytes spreading underneath the umbrella-shaped follicular area. (B1 and B2, Hematoxylin-eosin stain; C, immunohistochemistry HMB-45; D, immunohistochemistry AE1/AE3; E, Fontana-Masson stain; B-E, original magnifications: B-D, ×100; E, ×40.)
Journal of the American Academy of Dermatology  , DOI: ( /j.jaad )
Copyright © 2014 American Academy of Dermatology, Inc. Terms and Conditions

5. Fig 4
Pigmented actinic keratosis. Equivalent en face reflectance confocal microscopy (RCM) image of inner gray halo (IGH). A, Dermoscopic image of the lesion showing IGH (yellow square). B, Magnified dermoscopic detail of IGH. C, Magnified image of IGH with superimposed matching IGH drawing. D, RCM mosaic image, with selected area (yellow square) for step-sectioning images. E, Step image showing RCM counterpart of IGH: ring of normal honeycomb around the follicular area (yellow arrows) surrounded by disarranged bright keratinocytes. F, Deeper RCM step image of the same area at spinous-dermoepidermal junction layer level showing honeycomb disarrangement and ring of small polygonal bright cells surrounding the area of normal honeycomb around the follicles, following the follicular profile (yellow arrowheads), corresponding to the hyperpigmented basal keratinocytes seen on histology, which are responsible for the Tyndall effect seen on dermoscopy of IGH.
Journal of the American Academy of Dermatology  , DOI: ( /j.jaad )
Copyright © 2014 American Academy of Dermatology, Inc. Terms and Conditions