HEPATOBILIARY CYSTADENOMA AND CYSTADENOCARCINOMA - A LIGHT-MICROSCOPIC AND IMMUNOHISTOCHEMICAL STUDY OF 70 PATIENTS

Fifty-two hepatobiliary cystadenomas and 18 hepatobiliary cystadenocar cinomas were drawn from the files of the Armed Forces Institute of Pat hology and Rhode Island Hospital and studied in an attempt to correlat e light microscopic features of the tumors with immunohistochemical an d follow-up data. The cystadenoma patients ranged in age from 2 to 87 years at the time of initial diagnosis (mean, 45 years). All the cysta denomas were multilocular with benign cuboidal to columnar epithelium, and 44 (85%) had densely cellular spindle cell (''ovarian-like'') str omata; 96% were female. Fifty-one cystadenomas were macrocystic lesion s, typically lined by mucinous epithelium; one of the benign lesions w as a serous cystadenoma (microcystic adenoma) reminiscent of the more commonly encountered pancreatic lesion of the same name. The cystadeno carcinoma patients ranged in age from 24 to 90 years at the time of fi rst diagnosis (mean, 59 years); eight patients (44%) were male. All bu t one of the lesions were multilocular with malignant in situ (one cas e) or invasive tubulopapillary (15 cases), solid (one case), or adenos quamous (one case) epithelial components. Areas of preexisting benign cystadenoma were found in six (33%), an observation suggesting that be nign lesions may evolve into malignant ones in some patients. Most cys tadenomas and cystadenocarcinomas arose in the liver, a few in the ext rahepatic biliary system (including the gallbladder). On follow-up, th e cystadenoma patients in general were successfully treated by surgica l excision of the lesions in tote; patients treated by subtotal resect ion often had persistent symptomatic disease. Four cystadenocarcinoma patients died of their tumors; another two patients were alive with pe rsistent disease at last follow-up. In both the benign and the maligna nt lesions, most tumor cells were positive on immunohistochemical stai ning with antibodies to cytokeratin, epithelial membrane antigen, and carcinoembryonic antigen; scattered chromogranin-positive cells also a ppeared in a few tumors of both types. Immunohistochemistry did not yi eld a diagnostic immunoprofile to distinguish cystadenoma from cystade nocarcinoma or from other epithelial lesions arising within the abdomi nal cavity. At least two types of cystadenocarcinoma exist, one develo ping exclusively in female patients, usually accompanied by an ''ovari an-like'' stroma, which follows an indolent course; and the other, lac king the distinctive cellular stroma, seen in males, follows a more ag gressive course and is more likely to result in the patient's death fr om tumor. It remains an open question whether the cystadenocarcinomas lacking a mesenchymal stroma, which arise in women, will follow the sa me aggressive course as similar lesions arising in men.