The most probable diagnosis in the below specimen in a 20 year old female with mass abdomen, on removal of ovary shown below
Dysgerminoma:

It is the most common pure germ cell tumor of ovary.
Its solid, firm and non-cystic (solid tumor of young – first differential is dysgerminoma)
It corresponds to Seminoma.
It is common under the age of 20.
It is usually unilateral.
It is neutral.
It secrets placental alkaline phosphatase.
It may be associated is hypoplasia or aplasia of part of genital tract.
It is very radiosensitive.
It is potentially malignant with malignancy rate of 30-50%.

Endodermal sinus/yolk sac tumor is 2nd most common germ cell tumor.
Choriocarcinoma
Dysgerminoma
Embryonal cell tumor
Malignant teratoma