Objective: To describe the features of facial seborrheic keratosis, verruca plana, and nevus pigmentosus by dermatoscopy and reflective confocal microscope (RCM).
Study design: Cross-sectional observational study.
Place and duration of study: Dermatology Department of The Affiliated Hospital of Xuzhou Medical University from January 2017 to January 2019.
Methodology: Patients of either gender and age, clinically diagnosed as seborrheic keratosis, verruca plana, and nevus pigmentosus without any prior treatment, were enrolled. Patients with extremities and trunk involvement were excluded. One typical skin lesion was chosen from each patient and subjected to dermatoscopy and RCM separately; imaging features were recorded and analysed.
Results: A total of 402 patients (183 men and 219 women) between 6 and 88 years of age (mean age 41.8 years) were inducted. The duration of disease was between one week and 10 years. Seborrheic keratosis on dermatoscopy presented as acne-like openings (122/172; 70.93%, milia-like cysts (113/172; 65.70%), hairpin-like vessels (108/172; 62.79%, brain-like structures (103/172; 59.88%, worm-like pharyngeal margins (17/172; 9.88%), and fingerprint-like structures (8/172; 4.65%). On RCM, it showed epidermal cerebral gyrus structure (165/172; 95.93%), superficial vasodilatation and hyperemia (81/172; 47.09%), and keratinous cysts (73/172; 42.44%). Verruca plana on dermatoscopy showed a number of punctate hemorrhages scattered against a light-red background (108/114; 94.74%); on RCM it showed rose-like concentric structures (89/114; 78.07%). The features of nevus pigmentosus observed by dermatoscopy were homogeneous mode (23/52; 44.23%), light brown color (30/52; 57.69%) for intradermal nevus; mesh mode (18/41; 43.90%, dark brown color, little black dots and spherical structure (both 18/41; 43.90%) were visible for junctional nevus; globular mode, reticular and cobblestone structures (both 11/23; 47.83%) for compound nevus. On RCM, there were a few nevus cells visible within the dermal papilla (52/52; 100%) for intradermal nevus; bright pebble-like structures accumulated in the basal layer, nested round and elliptical nevus cells (40/41; 97.56%) for junctional nevus; nevus cells in the epidermis and dermis (21/23; 91.30%) for compound nevus.
Conclusion: Used in combination with clinical manifestations, the application of dermatoscopy and RCM may help distinguish seborrheic keratosis, verruca plana, and nevus pigmentosus on the basis of their respective dermatoscopic and RCM features. Key Words: Dermatoscopy, Reflective confocal microscope, Seborrheic keratosis, Verruca plana, Nevus pigmentosus, Brain-like structures, Rose-like structure.