Clear cell hidradenocarcinoma--a case report with unusual in situ malignant changes.

Clear cell hidradenocarcinoma is a rare tumour, the histogenesis of which has been much debated in the past. However, it is now considered a tumour of sweat gland origin. Presented herewith is a report of a case with unusual histological features of in situ malignant changes within sweat glands. These changes very closely simulate lobular cancerisation of the breast. On reviewing the English literature on the histopathology of sweat gland tumours, we have not found similar histological findings. These histological findings provide supportive evidence of the sweat gland origin of these tumours.