Small melanomas: a clinical study on 270 consecutive cases of cutaneous melanoma

The ABCD (asymmetry, border, colour, dimension) criteria represent a commonly used clinical guide for the diagnosis of early cutaneous melanoma (CM). This guide stipulates that CMs usually are more than 6 mm in diameter. The purpose of this retrospective study was to establish the frequency of occurrence of small (< or =6 mm) melanomas in a clinical context. Our series consisted of 270 consecutive CMs (39 in situ and 231 invasive) in 267 patients. Of these 270 lesions, 47 (17%) were small lesions, ranging from 2 to 6 mm in maximum linear extent, with a median value of 5 mm. Of these small lesions, 14 were in situ and 33 Invasive CMs. The median thickness of the 33 small invasive lesions was 0.31 mm. The clinical features of CMs were sufficiently distinctive to suggest a diagnosis of CM in half of the cases, irrespective of the invasiveness or not of the lesions. Dermatoscopy was performed on 36 of the small lesions and achieved a correct diagnosis in 72% of the cases. The combination of simple visual examination with dermatoscopy allowed a higher rate of recognition (86%) than when the two methods were considered separately. Results of our study show that small CMs represent a considerable clinical subset of all CMs. Clinicians must be aware of this fact in their diagnostic activity.