Expression of estrogen and progesterone receptors and inhibin-alpha in hepatobiliary cystadenoma: an immunohistochemical study.

To further characterize the immunohistochemical features of hepatobiliary cystadenoma with mesenchymal stroma, a battery of stains was performed on nine typical cases. All nine tumors had been resected from female patients who ranged in age from 30 to 59 years. Freshly cut sections were stained with antibodies to estrogen receptor (ER), progesterone receptor (PR), alpha-smooth muscle actin (SMA), inhibin-alpha, and cytokeratins (CK) 7, 8, 18, and 19. Nuclear staining of the mesenchymal stromal cells for ER and PR was present in all and seven out of nine cases, respectively. A strong cytoplasmic staining of the mesenchymal stromal cells for SMA was seen in all cases. A patchy pale cytoplasmic staining of the tumor epithelium for ER and PR was seen in five out of nine and four out of nine cases, respectively. Immunoreactivity of luteinized stromal cell for inhibin-alpha was documented in three out of nine cases. All tumors (nine out of nine) demonstrated strong cytoplasmic positivity of the epithelial lining of the cysts to CK7, CK8, CK18, and CK19, typical of biliary-type epithelium. The expression of ER, PR, and inhibin-alpha in the ovarian-like stroma supports the likely hormonal dependence of this tumor and probably explains its almost exclusive occurrence in women.