The presence of different types of intermediate filaments (IMF) was studied in normal ovarial tissue and in ovarian
tumors. The coelomic epithelium contained both
prekeratin and
vimentin, but the graafian follicle cells and stromal cells contained only
vimentin. In normal ovaries,
desmin positivity was confined to the arterial walls.
Tumors derived from surface epithelium, including Brenner
tumors, expressed
prekeratin in the epithelial cells, whereas
sex cord-stromal tumors showed only
vimentin-type IMF. Germinal
tumors also showed only
vimentin-type IMF, whereas differentiated
teratomas expressed the IMF of the corresponding differentiation line, as recognized by light microscopy. Thus, the skin, skin appendages, and other epithelial components of
dermoid cysts showed
prekeratin; mesenchymal components showed
vimentin (but smooth muscle cells,
desmin), and glial-like areas showed
glial fibrillary acidic protein. The results suggest that expression of IMF in ovarian
tumors corresponds to the filament expression of the parental tissues and that the typing of IMF can be used in the differential diagnosis between ovarian
tumors of different histogenesis.