Malignant struma ovarii with ascites: a clinicopathological and electron microscopical study

Summary

An ovarian mass in association with gross ascites proved to be a malignant struma ovarii in a cystic tratoma. The tumour consisted of follicular structures containing colloid, and of sheets of cells forming abortive follicles without colloid. Capsular and vascular invasion and atypical cell changes indicated malignancy. Well developed functional complexes between tumour cells and fenestrated endothelial walls in the capillaries of the tumour stroma were electron microscopical features confirming the presence of thyroid tissue No light or electron microscopical features of carcinoid tumour were found.