Solid teratomas and mixed müllerian tumors of the ovary: a clinical, histological, and immunocytochemical comparative study.

The differential diagnosis between solid teratomas and malignant mixed Müllerian tumors (MMTs) can be difficult, because both tumours have an epithelial as well as a mesenchymal component. Sometimes an MMT is incorrectly diagnosed as a solid teratoma. This has prognostic and therapeutic consequences, because MMTs have a worse prognosis. In this study 20 solid ovarian teratomas and 15 MMTs of the ovary have been compared according to their clinical, histomorphological, and immunocytochemical characteristics. Teratomas occur in the younger age group and are characterized by the presence of argyrophil cells which are immunoreactive to a wide range of neurohormonal peptides and are in addition characterized by the presence of GFAP immunoreactive tissues (glial fibrillar acidic protein). MMTs occur in the older age group and are characterized by the presence of sarcomatous elements and by the absence of an organoid arrangement, neuroectoderm, skin, argyrophilia, and immunoreactivity to GFAP and neurofilament.