Background: Yolk sac tumor (YST) of the ovary is a rare neoplasm typically affecting children and young women. We describe the cytomorphology of this tumor in ascitic fluid and discuss its differential diagnosis from other neoplasms.
Case: Smear preparations of the ascitic fluid showed a predominance of clusters of malignant cells with vacuolated cytoplasm, mimicking a mucinous adenocarcinoma, and fewer syncytial-like and glandular structures.