Ovarian hepatoid yolk sac tumours: morphological, immunohistochemical and ultrastructural features.

OBJECTIVE

The clinicopathological, immunohistochemical and ultrastructural features of two ovarian hepatoid yolk sac tumours (H-YST) from our files are reviewed.

RESULTS

Using avidin-biotin-peroxidase complex technique, the immunoprofile of these tumours was compared to that of a classic yolk sac tumour and to that previously reported for hepatocellular carcinomas. The clinicopathological and morphological features of our cases are similar to the seven previously reported ovarian cases. This rare germ cell tumour occurs in young females (mean age = 17.6 years) and presents most commonly with abdominal pain and a large ovarian mass (average size = 140 mm). Histologically, the tumours display a striking resemblance to hepatocellular carcinoma. The absence of an associated typical pattern of yolk sac tumour or other germ cell neoplasm may make it difficult to recognize the germ cell origin of this lesion. Our cases demonstrated positive staining for alpha-fetoprotein and alpha-1-antitrypsin. In addition, there was immunoreactivity with polyclonal carcinoembryonic antigen (CEA) antiserum in a canalicular pattern, focal staining for inhibin, oestrogen and progesterone receptors and absence of immunoreactivity for CK7 that contrasts with the immunophenotype of a usual yolk sac tumour.

CONCLUSIONS

Ovarian H-YST and hepatocellular carcinoma share a similar immunoprofile. Ovarian H-YST is a highly aggressive tumour, most patients exhibit recurrence or die of disease within 2 years of diagnosis.