Cystadenoma with mesenchymal stroma (CMS) in the liver and bile ducts. A clinicopathologic study of 17 cases, 4 with malignant change

This study of 17 cases describes a homogeneous clinicopathologic group of tumors previously subsumed under the general term, hepatobiliary cystadenoma. This unique group of neoplasms that the authors have termed “cystadenoma with mesenchymal stroma” (CMS), occurred exclusively in women and showed two essential tumor components: (I) a cyst lining of columnar to cuboidal, much secreting epithelium; and (2) a moderately to densely cellular stroma composed of spindle (rarely oval) cells. The stromal element appeared similar to primitive mesenchyme, both on light and electron microscopic study, showing variable differentiation toward fibroblasts, smooth muscle, adipose tissue and capillaries. Cases of hepatobiliary “cystadenoma” in the literature with histology similar to CMS had similar sex and age incidences, while histologically dissimilar cases, lacking the mesenchymal stroma, had significantly different parameters. Four cases of CMS in this series showed malignant change that was manifested as papillary adenocarcinoma, suggesting the need for complete surgical removal of these premalignant neoplasms. Cancer 56:1434-1445, 1985. EPATOBILIARY CYSTADENOMAS are rare cystic tuH mors occumng in the liver parenchyma and bile ducts that grow to a large size and require surgical intervention. Most of the literature concerning these neoplasms consists of single case reports and literature reviews. The largest of the (rarely) reported series (seven cases) is that of Ishak ef al.’ The original suggestion that the term “cystadenoma” be confined to multilocular cystic tumors lined by mucin secreting columnar epithelium overlying a dense cellular (mesenchymal) stroma2 has proved to be inadequate as review of the literature reveals that a number of the reported cystadenoma cases lack at least the cellular (mesenchymal) stroma. We have now studied 22 cases of cystic hepatic tumors submitted as cystadenomas, 5 in males and 17 in females. All those in females had features meeting the original criteria,2 while the cystadenomas in males differed in that they all lacked mesenchymal stroma. Cystadenomas that are