What's the cyst on this woman's head?
This 82 year old woman was sceptical of doctors and Dr Mike Wyndham had rarely seen her over the years. But a cyst that bled when she brushed her hair brought her to the surgery
This 82 year old lady must have been one of the first patients I saw when I joined the practice. She was extremely single-minded and resented any intervention from the medical profession and I'd only seen her on a handful of occasions since. To get some idea of what she was like, she was a firm refuser of influenza jabs having never had the flu and thought that ‘this swine flu thing was a complete nonsense.'
So why had she come? Well, she'd noticed a cyst on her head which had been growing over the last year. It had not bothered her too much till recently but it was now becoming a nuisance. Every time she brushed her hair, the cyst would bleed and on the last occasion it had bled most profusely.
There was certainly a cystic lesion with a scab on the side. Presumably, the scab had formed where she had traumatised the lesion with her brush. Light exposure certainly predisposes men with their potentially balding heads to skin cancer but she had a good head of hair.
• Epidermoid cyst
• Squamous cell carcinoma of the skin
• Basal cell carcinoma
Epidermoid cysts certainly occur on the scalp but they are usually smooth and the surface of this skin lesion appeared to be irregular. Of course, the surface may have been damaged by the hair brush. Squamous cell carcinomas may develop in an actinic keratosis and so may be scaly initially. If left, they may go on to ulcerate and form a crust on the surface. Not quite the appearance of this lesion. Although the scalp may get a great deal of light exposure, particularly in the bald male, it is not a common place for a basal cell carcinoma to develop. There was certainly one telangiectasis present but it did not appear that nodular or pigmented.
The hidden clue
I felt it was going to be a challenge to get a sceptic like her to deal with her problem and so I set about giving her the differential diagnosis. I was only a little way into my explanation, when she interrupted me. ‘You know, as long as I can remember, there has been a mole on my scalp. It has never bothered me, so I left it alone.' I hadn't really seen this, and so I took another look at her scalp.
Getting on the right track
The lesion did seem to have a flatter component to it in the surrounds and there was little hair growing in this area. This suggested that the original underlying skin lesion was a sebaceous naevus. There is a definite risk of development of basal call carcinomas (bcc) in up to 25%. Patricia, surprisingly, was happy to accept my referral to a dermatologist who confirmed the BCC.
Dr Mike Wyndham is a GP in Edgware, north London