Hepatobiliary cystadenoma with mesenchymal stroma: expression of oestrogen receptors in formalin-fixed tissue.

We report three cases of hepatobiliary cystadenoma with mesenchymal stroma in which oestrogen receptor immunostaining was carried out, after using a microwave method of antigen retrieval. In one of the tumours immunoreactivity for oestrogen receptors was demonstrated within the mesenchymal stromal cells. The presence of oestrogen receptors supports the theory that oestrogens act as tumour promoters and may explain the female predilection.