Giant clear cell acanthoma

Sir, Clear cell acanthoma is a benign tumour first described in 1962.1 There have been two previous reports of giant clear cell acanthoma,2,3 one of these on the buttock. There has also been a report of a clear cell acanthoma arising in a plaque of psoriasis on the buttock.4 A 78‐year‐old woman presented with an acute myocardial infarction and was treated with thrombolysis. She had a 20‐year history of psoriasis which had been controlled for the last 5 years with oral methotrexate 12·5 mg weekly. While in hospital she developed blood‐stained serous discharge from a lesion on the buttock which had slowly grown over 12 years. It was a pink, cerebriform lesion measuring 60 × 40 × 20 mm, with a velvety surface and sharply demarcated edges (Fig. 1a). The rather unusual appearance of this lesion made the initial clinical diagnosis difficult although a very well differentiated squamous cell carcinoma was considered.