Editor,—The signet ring cell carcinoma of the eccrine sweat gland is a very rare tumour of the eyelid. Only six cases have been published up to now. There is a preponderance of males; only one woman was affected. The patients' ages ranged from 47 to 78 years. This tumour shares some histological features with breast carcinoma, the metastasis of which represents the most important differential diagnosis—Indian file formations, signet ring cells, and expression of oestrogen, as well as progesterone, receptors. One significant difference is that the positive staining for those hormone receptors is found mainly in the cytoplasm in signet ring cell carcinoma, in contrast with the nuclear staining of breast carcinomas cells.

Different treatment modalities have been applied in cases of eccrine sweat gland carcinoma. Our case demonstrates that tumour control can be achieved with radiotherapy alone despite extensive orbital involvement.