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Treat pigmented skin lesions with care

01 August 2003

Mr F was a forester in his forties. He went to see Dr N, his GP, for advice about two skin lesions – one appeared to be a sebaceous cyst on the left shoulder, the other a pigmented lesion on his chest. Dr N booked Mr F in to have the lesions removed on the minor-surgery list at the practice.

The surgery was carried out a month later. The sebaceous cyst was removed in its entirety, and the lesion on the chest cauterised, in the belief that it was a naevus. No samples were sent for histology.

A year later, Mr F returned to the surgery where he consulted another of the practice partners. He had developed a swollen, inflamed cyst at the site of the original lesion on his chest. It was treated as an infected cyst and Mr F was given antibiotics and referred to the general surgical unit the next day to have the cyst removed.

Unfortunately, it transpired that the lesion was in fact a malignant melanoma. There was evidence of metastatic spread to lymph nodes in the axilla, and more distantly, confirmed by a CT scan. Despite treatment, Mr F died two years later.

An action against Dr N alleged sub-standard clinical management for cauterising a pigmented lesion which, it was claimed, was known to have bled.

Expert opinion

According to experts we consulted, the lesion should have been excised with a margin and sent for histological analysis, rather than cauterised.

One expert commented, ‘It has certainly been the case in the past that lesions sent down with a benign diagnosis have been found on histology to be malignant. I therefore believe that all GPs who carry out minor surgery should send all lesions removed for histology.’

The case was settled, and an award made on the basis that Mr F’s chances of 10-year survival of his melanoma had been reduced from about 50% when initially seen, to about 15% when the diagnosis was finally made.

Learning points

Skin cancers can present with a variety of atypical appearances, making diagnosis difficult. As this case demonstrates, it is wise to obtain a histological diagnosis after excision with a margin. Any pigmented skin lesion for excision, regardless of how long it is purported to have been present, should be treated as a potential melanoma. This is especially true if the lesion has bled, crusted, been itchy or developed satellite lesions.