1. Dermoscopy of acral pigmented lesions
Kat Nightingale
Associate Specialist
Bristol Royal Infirmary

2. Acral melanoma ALM – 2-3% of all melanomas
1.8 per million person years
36% of melanomas in black skin
<1% of melanomas in white skin
5 year survival 80.3%
10 year survival 67.5%
Feet >hands

3. Acral skin structure Thick compact cornified layer
Dermatoglyphics – ridges and furrows
Absent hair follicles
Well developed eccrine ducts
2 types Rete ridges - Crista profunda limitans - furrow
Crista profunda intermedia – ridge
Melanocytes distributed mainly in the CPL

5. Acral dermoscopy patterns – acquired
Parallel furrow %
Lattice – 15% arch area
Fibrillar – 10-20% Pressure bearing areas
Parallel ridge - melanoma
Globular
Acral reticular
Homogenous
Transition

9. Ink Furrow test

10. Lattice pattern – 15%
Peripheral palms and soles
Where typical parallel pattern lost

11. Artifactual modification of the parallel furrow pattern
Artifactual modification of the parallel furrow pattern. Obliquely organised cornified layer due to body wt. Very rarely found on palmar skin.

12. Benign homogenous, globular, atypical and reticular acral dermoscopy patterns

13. Transition zone patterns
Prominent proliferation of meloncytes in solitary units within the epidermis. Miimics melanoma in situ. Densly arranged branching or reticular pigmentation.

14. Acral dermsocopy patterns - congenital
Parallel furrow
Crista dotted
Peas-in-a-pod – combination of above
Crista reticulated

15. From: Dermoscopic Characteristics of Congenital Melanocytic Nevi Affecting Acral Volar Skin
Arch Dermatol. 2011;147(7): doi: /archdermatol
Crista dotted and peas in a pod

18. Peas in a pod

19. Acral melanoma patterns
Parallel ridge- 89% sensitive 99% specific (Significance of dermoscopic patterns in detecting malignant melanoma on acral volar skin: results of a multicenter study in Japan.Saida T, Miyazaki A, Oguchi S, Ishihara Y, Yamazaki Y, Murase S, Yoshikawa S, Tsuchida T, Kawabata Y, Tamaki K Arch Dermatol Oct;140(10): )
Multicomponent - irregular diffuse pigmentation, abrupt edges, serrated pattern, peripheral irregular dots and globules, and/or blue-white veil.
Advanced- changes similar to non-acral skin
Sensitive- 89% specificity 99%

20. The 3-step dermoscopic algorithm
Step 1 – The lesion is examined for the presence of the parallel ridge pattern. If the parallel ridge pattern is found in any part of the lesion, the lesion should be biopsied regardless of the size. If the lesion does not show the parallel ridge pattern, proceed to Step 2.
●Step 2 – The lesion is examined for the presence of one or an orderly combination of the typical benign dermoscopic patterns (ie, typical parallel furrow pattern, typical lattice-like pattern, regular fibrillar pattern). If the lesion shows one or a combination of two or three typical benign patterns, further dermoscopic follow-up is not needed. If the lesion shows equivocal dermoscopic features (ie, absence of any typical/regular patterns) proceed to Step 3.
●Step 3 – The maximum diameter of lesions that do not show typical benign patterns is measured. Lesions >7 mm should be excised or biopsied for histopathologic evaluation. Lesions ≤7 mm should be monitored clinically and dermoscopically at three- to six-month intervals.

22. References
Saida T, Miyazaki A, Oguchi S, Ishihara Y, Yamazaki Y, Murase S, Yoshikawa S, Tsuchida T, Kawabata Y, Tamaki K: Significance of dermoscopic patterns in detecting malignant melanoma on acral volar skin: results of a multicenter study in Japan. Arch Dermatol 2004, 140:
Altamura D, Altobelli E, Micantonio T, Piccolo D, Fargnoli MC, Peris K: Dermoscopic patterns of acral melanocytic nevi and melanomas in a white population in central Italy. Arch Dermatol 2006, 142:
Malvehy J, Puig S: Dermoscopic patterns of benign volar melanocytic lesions in patients with atypical mole syndrome. Arch Dermatol 2004, 140:
Miyazaki A, Saida T, Koga H, Oguchi S, Suzuki T, Tsuchida T: Anatomical And histopathological correlates of the dermoscopic patterns seen in melanocytic nevi on the sole: a retrospective study. J Am Acad Dermatol 2005, 53: