Digging for gold in a dermatology clinic

Abstract

Conflict of interest: none declared. An 85‐year‐old woman with a history of habitual excessive sun exposure presented with a lesion on her right eye. On physical examination, a nodule was seen on the right inner canthus (Fig. 1), which was diagnosed as a suspected basal cell carcinoma (BCC). As the lesion was at the same site of a previous BCC that had been treated with radiotherapy over 50 years previously, it was therefore suspected to be a local recurrence. The lesion was excised, but there was no evidence of any dysplasia or BCC, but scarring tissue was seen, which was found to contain a 5‐mm gold‐seed rod (Fig. 2). This gold seed was the permanent implant used (gold‐198) to treat the patient’s BCC over 50 years ago. Such an implant has a short irradiation half‐life of only a few days. A BCC is a slow‐growing malignant tumour, also known as a ‘rodent ulcer’. The first description of a rodent ulcer was made by Jacob in 1827, who stated: ‘The characteristic features of this disease are the slowness of its progress, the peculiar condition of the edges and surface of the ulcer, and the comparatively inconsiderable suffering produced by it, its incurable nature except by extirpation, and it not contaminating the neighbouring lymphatic glands’.1 Gold‐seed implants were used for the treatment of BCCs in the first half of the 20th century, and there were two types: ‘threaded’ or ‘ordinary’ implants. The ‘threaded’ implants used threaded gold seeds, which were removed after a period of 5–7 days, whereas the ‘ordinary’ implants were permanently placed, as in our patient. The advantages of gold‐198 over other radioisotopes such as radium‐222 in the treatment of BCCs were its low gamma energy (411 KV) and short half‐life (2.7 days).2