CASE 68: A LUMP ON THE SKIN
History
A 66-year-old farmer is referred to a dermatologist for a lesion on his forearm. It is raised,
1.5 cm in diameter, with an irregular margin and a slightly ulcerated centre. It is painless
and has appeared over the last 6–8 months. Fifteen years earlier the patient had had a
cadaveric renal transplant for renal failure due to chronic glomerulonephritis caused by
immunoglobulin A (IgA) nephropathy. This has functioned well, and he has required con-
tinuous immunosuppression. Originally this was with prednisolone and azathioprine, but
later it was converted to ciclosporin. His only other medication is propranalol for hyper-
tension which he has taken for 20 years. There is no other relevant past or family history.
He has never smoked, and drinks 3–6 units of alcohol per week.
Examination
The lesion is as described on the right forearm and there are several solar hyperkeratoses
on his cheeks, forehead and scalp (he is bald). The blood pressure is 144/82 mmHg. No other
abnormalities are found apart from the transplant kidney in the right iliac fossa.
NormalHaemoglobin 15.4 g/dL 13.3–17.7 g/dL
White cell count 4.6% 109 /L 3.9–10.6% 109 /L
Platelets 356 % 109 /L 150–440% 109 /L
Sodium 141 mmol/L 135–145 mmol/L
Potassium 4.2 mmol/L 3.5–5.0 mmol/L
Bicarbonate 29 mmol/L 24–30 mmol/L
Urea 6.7 mmol/L 2.5–6.7 mmol/L
Creatinine 118 &mol/L 70–120&mol/L
Glucose 5.6 mmol/L 4.0–6.0 mmol/LUrinalysis'protein; no bloodINVESTIGATIONS
Questions
- What is the likely diagnosis of the lesion on the forearm?
- What factors have contributed to its development?