Extragonadal yolk sac tumor outside of the midline of the body: a case report of a child with a yolk sac tumor of the pontocerebellar angle.

Yolk sac tumor is a rare germ cell neoplasm occurring mainly in the gonads. Extragonadal yolk sac tumor is a very rare malignancy; its main distribution is along the midline of the body at three principal sites: mediastinum, central nervous system and retroperitoneum. Most yolk sac tumors are diagnosed between seven months and three years of age. We report a case of primary yolk sac tumor in a 13-month-old child. The tumor was located in the pontocerebellar angle, an atypical location that may not have suggested a yolk sac tumor as first diagnosis. We want to highlight the importance of performing tumor marker measurements during the first year of life, also for tumors located away from the midline.