Primary retroperitoneal teratoma in adults: presentation of two cases and review of the literature.

Retroperitoneal teratomas are rare in adults; they are malignant in 25.8% of cases. The authors report two benign cases in which radiologic examination was essential in establishing the diagnosis. Irregular calcifications, which are visible in 61.5% of reported cases, cannot be considered a sign of benignity, since 12.5% of calcified tumors were malignant. Because of the indeterminate course of the disease, surgical removal is indispensable.