The hunt for baby melanomas: a prospective study of the dermoscopy features on 100 small melanoma cases with in vivo surface diameters up to a maximum of 6mm.

John Pyne; Sarah MacDonald; Susan  Beale; Esther  Myint; Wei Huang; Simon Clark; Andrew  Trang

doi:10.5826/dpc.1204a197

The hunt for baby melanomas: a prospective study of the dermoscopy features on 100 small melanoma cases with in vivo surface diameters up to a maximum of 6mm.

Authors

John Pyne Faculty of Medicine, The University of New South Wales, Sydney, Australia
Sarah MacDonald Faculty of Medicine, The University of New South Wales, Sydney, Australia
Susan Beale Faculty of Medicine, The University of New South Wales, Sydney, Australia
Esther Myint Faculty of Medicine, The University of New South Wales, Sydney, Australia
Wei Huang Faculty of Medicine, The University of New South Wales, Sydney, Australia
Simon Clark Faculty of Medicine, The University of New South Wales, Sydney, Australia
Andrew Trang Faculty of Medicine, The University of New South Wales, Sydney, Australia

Keywords:

early small melanoma, dermoscopy, confocal microscopy, pigmented hair follicles, pseudopods, polygons.

Abstract

Background:: Early diagnosis can improve melanoma prognosis. Dermoscopy can enhance early melanoma recognition.

Objectives: Examine the dermoscopy features of early melanoma up to a maximum surface diameter of 6mm.

Methods: Consecutive melanoma cases were collected from two medical practices in Sydney, Australia 2019-2021. Dermoscopy features were recorded for melanomas by maximum surface diameter, to the nearest 0.1 mm, to a limit of 6mm.

Results: Total cases numbered 100; with males (n=48) and females (n=52), melanoma in situ (MIS, n=96) and invasive (n=4). The most frequent anatomic sites on both males and females were back (males n=20, females n=16) then knee or leg (males n=8, females n=12). Minimum respective MIS diameters for males/females was 1.2/2.0mm and for invasive cases 2.0/3.4mm. Highest frequency dermoscopy features were: light brown, dark brown, grey and asymmetric melanoma shape. Brown pigment in hair follicles were more frequent on legs compared to other anatomic sites [OR 14.6, 95%CI (1.29-165.17), p 0.03]. Pseudopods were substantially increased in frequency comparing diameters less than 4mm with 4 up to 6mm [OR 8.81, 95%CI (1.05-73.9), p 0.004]. Structureless area cases recorded increased grey [OR 7.08, 95%CI (1.61-31.11) p=0.01]. Melanomas with edge angulation were noted in 20-50% of cases across diameters 1-6mm, less frequent were pigmented circles and polygons.

Conclusion: Watch out! MIS presented with a surface diameter of just 1.2 mm and invasive melanoma 2.5mm. Pseudopods were a strong clue to melanomas with a surface diameter less than 5mm. We found melanomas on leg sites displayed more frequent pigmented hair follicles.

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