A 56-year-old man was referred for assessment of a pigmented lesion on his cheek that had been present for 7 years. Dermoscopy of the lesion revealed slate gray and brown dots, an annular granular pattern of gray dots, and asymmetric pigmented follicular openings. A biopsy determined the lesion was a pigmented actinic keratosis. Pigmented actinic keratosis can be difficult to distinguish from lentigo maligna based on clinical and dermoscopic features such as gray or brown dots and globules, and asymmetric pigmented follicles.

1. Pigmented actinic keratosis simulating a Lentigo maligna . F. Peral Rubio, M.D. Department of Dermatology Hospital Universitario Virgen Macarena, Seville, Spain

2. Pigmented actinic keratosis simulating a Lentigo maligna . A 56-years-old men. The patient was referred to us for the assessment of a pigmented lesion on the cheek 7 years previously.

8. Pigmented actinic keratosis simulating a Lentigo maligna The dermoscopy revealed: In the upper -Slate gray and brown dots . -Annular granular pattern of gray dots. - Asymmetric pigmented follicular openings In the middle and lower: - E rythematous pseudonetwork, in which there are prominent hair follicles surrounded by a white halo.

9. Annular granular pattern of gray dots

10. Slate gray and brown dots

11. Asymmetric pigmented follicular openings

12. E rythematous pseudonetwork

13. Pigmented actinic keratosis simulating a Lentigo maligna A biopsy was performed on the pigmented area and pathology revealed a pigmented actinic keratosis.

14. Pigmented actinic keratosis simulating a Lentigo maligna Dermoscopy of no pigmented actinic keratosis: Typical feature is a composite pattern named “strawberry ” characterized by: A erythematous pseudonetwork on facial skin, in which there are prominent hair follicles surrounded by a white halo. If the folllicle has a yellow central plaque they may look like a target.

15. Pigmented actinic keratosis simulating a Lentigo maligna Dermoscopy of pigmented actinic keratosis : Facial pigmented actinic keratosis is a differential diagnosis of lentigo maligna because it can have the same clinical and dermoscopic aspects: Gray or brown dots and globules. Asymmetric pigmented follicles. Annular-granular structures. Possible clues for pigmented actinic keratosis are scales and a superficial broken-up network usually not present in lentigo maligna.

16. Pigmented actinic keratosis simulating a Lentigo maligna Conclusions The dermatoscopical picture of pigmented actinic keratosis in this patient was practically indistinguishable from the early stage of Lentigo Maligna. Pigmented actinic keratosis has a striking similarity to lentigo maligna in clinical and dermatoscopic features, thus representing a diagnostic challange.

17. Pigmented actinic keratosis simulating a Lentigo maligna . F. Peral Rubio, M.D. Department of Dermatology Hospital Universitario Virgen Macarena, Seville, Spain