Definition : a primitive germ cell tumor, similar to testicular seminoma.
Synopsis :
90% are apparently unilateral, but occult foci of dysgerminoma can be detected by biopsy of the contralateral ovary in 10% of cases
monotonous proliferation of primitive germ cells
connective tissue septa containing variable amounts of chronic inflammatory cells
Immunohistochemistry :
most are vimentin + and PLAP + (placental-like alkaline phosphatase)
CD117 (c-kit) +
inconstant + to : cytokeratins, desmin, GFAP, CEA and S-100 protein
Etiology and evolution :
the vast majority have no precursor lesion
may arise from gonadoblastoma
may be a precursor to other primitive germ cell tumors