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What is this rapidly growing lesion on this man’s face?

When this man presented with a ‘nasty’ looking lesion on his face, Dr Keith Hopcroft initially thought that the most likely diagnosis was basal cell carcinoma, but could it be something else?

The patient

The 62-year-old man had hardly attended in 15 years, so I was expecting some significant pathology when he arrived in surgery and the problem was apparent the moment he sat down.

‘It started as a tiny lump four weeks ago,’ he explained, pointing to the lesion on his face. ‘And it’s grown to this size over three or four weeks.’ It wasn’t painful, there were no skin lesions elsewhere, and he was otherwise well.

First instinct

Given the context, the look of the lesion and its rapid growth, I immediately assumed I was dealing with a skin malignancy. A brief examination did nothing to steer me away from this conclusion. It looked ‘nasty’, with obvious central ulceration, and was in a sun-exposed area – though there were no regional lymph nodes palpable.

Differential diagnosis

• Basal cell carcinoma

• Squamous cell carcinoma

• Keratoacanthoma

• Cutaneous horn

• Seborrheic wart

• Skin metastasis

The look of the lesion – with the central ulceration and rather rolled, pearly edges – suggested BCC as the most likely diagnosis. But the rapid onset and impressive size of the lesion seemed atypical. Which raised the possibility of a SCC – this was a better fit with the history, and the appearance was certainly suggestive.

Another malignant possibility was a skin secondary – but as there was no past history or suggestive symptoms of a primary, and he remained well, this seemed unlikely.

Which left some benign skin lesions in the differential. A cutaneous horn or seborrheic wart seemed unlikely, unless they had been significantly traumatised, perhaps through shaving. Besides, the rapid onset wasn’t typical of either lesion – though it did suggest that a keratoacanthoma should be included in the differential. The appearance was suggestive, too.

The hidden clue

Pondering the precise diagnosis seemed academic, as it was clear that this patient needed to see a dermatologist – under the two-week rule, given the distinct possibility of SCC.

So when the patient reappeared on my list a month or so later, I fully expected him to have a scar on his face where the lesion had been. Unfortunately, due to an appointment mix-up, the excision planned by the dermatologist had been delayed.

In fact, the patient had attended to ask whether it was necessary at all – because, as he correctly pointed out, the lesion seemed to be shrinking.

This pretty much gave the diagnosis away: apparent involution would clearly be an odd pattern of growth for a malignancy, but absolutely typical of a keratoacanthoma.

Getting on the right track

Despite the apparent improvement, I encouraged him to attend for the planned surgery. Excision tends to give a better cosmetic appearance than allowing a keratoacanthoma to resolve spontaneously – and it provides histology to help eliminate the tiny residual doubt about malignancy.

Another few weeks later, the patient did present with a scar, to enquire after his results – which confirmed a keratoacanthoma.

Dr Keith Hopcroft is a GP in Laindon, Essex

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