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 6 mm

INTRODUCTION: 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 6 mm. 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 6 mm. 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 1.2/2.0 mm and for invasive cases 2.0/3.4 mm. Highest frequency dermoscopy features were: light brown, dark brown, gray and asymmetric melanoma shape. Brown pigment in hair follicles were more frequent on legs compared to other anatomic sites (odds ratio [OR] 14.6; 95% CI 1.29–165.17, P 0.03). Pseudopods were substantially increased in frequency comparing diameters less than 4 mm with 4 up to 6 mm (OR 8.81; 95% CI 1.05–73.9, P 0.004). Structureless area cases recorded increased gray (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 1–6 mm, less frequent were pigmented circles and polygons. CONCLUSIONS: Watch out! MIS presented with a surface diameter of just 1.2 mm and invasive melanoma 2.5 mm. 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.