Differentiating moles from melanoma

Differentiating moles from melanoma

14 July 2017

Melanomas are often hard to differentiate from moles, making early recognition a challenge for many doctors and patients. Surgery is in fact required to confirm a diagnosis of melanoma.

One way that melanoma is differentiated from moles is by observing a change in shape or colour, as melanoma cells are continuously dividing. When we monitor a lesion with close-up photography, known as dermoscopy, over three months most moles will not change whereas most melanomas will change. This technique is known as short-term dermoscopy digital monitoring.

A new technology for diagnosing melanoma has been developed to improve clinical accuracy. Electrical impedance spectroscopy (EIS) is a non-invasive diagnostic technique that evaluates the lesion by applying alternating electric current. There are electrical differences between benign well-organised moles and malignant chaotic melanomas.

Researchers at Melanoma Institute Australia recently evaluated this technology to see if a lesion with a low score using EIS could be dismissed as completely benign and not need monitoring. They also evaluated if a lesion with a very high score should be removed immediately, avoiding unnecessary and potentially dangerous delay.

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The researchers found that using EIS can avoid the need for follow up in just under half of all cases. They also noted that using EIS the first time a patient is monitored can enable early excision of a melanoma without the usual delay of 3-monthly monitoring. This was the case in 83% of all the melanoma cases studied.

Publication: Rocha L, Menzies SW, Lo S, Avramidis M, Khoury R, Jackett L and Guitera P. Analysis of an electrical impedance spectroscopy system in short-term digital dermoscopy imaging of melanocytic lesions. Br J Dermatol. 2017 Apr 19. doi: 10.1111/bjd.15595. [Epub ahead of print]