Extramammary Paget's disease

Summary Extramammary Paget's disease remains a difficult clinical diagnosis and, though biopsy readily establishes the presence of a tumour with an intraepidermal spread, this needs further study so that other tumours with a similar pattern of spread may be excluded. We advocate the use of a panel of readily available peroxidase‐labelled antisera to cell markers and antigens in addition to conventional special stains to achieve this purpose. The disease often extends beyond the clinically abnormal area and an underlying sweat gland carcinoma may be present: this was so in five of the six cases presented. Wide surgical excision with a check on limits of clearance is recommended.