Sacrococcygeal Yolk Sac Tumor in a Two-Year-Old Girl With Multiple Metastases: A Case Report

Sacrococcygeal yolk sac tumor (YST) is an infrequent extra-gonadal malignant germ cell tumor (GCT) that occurs exclusively within the first two years of life. A two-year-old girl came with a massive mass on her left buttock, which continued to grow, and within three months had become extremely large and hindered her from walking. Physical examination revealed a sacrococcygeal mass of 15 cm in diameter. Multislice CT showed an intraluminal inferior cava vein mass extending into the pelvic cavity with coccygeal osseous destruction, pulmonary metastasis, and multiple hepatic metastases. Laboratory data revealed elevated tumor marker values for alpha-feto-protein (AFP), lactate dehydrogenase (LDH), and Ca-125. Cytopathology following fine needle aspiration biopsy evaluation of the smear sample revealed a cellular tumor with pseudo glandular, microcystic, and solid patterns. The cytopathology did not show pathognomic findings. An immunocytochemistry (IHC) examination of the cell block showed a positive result for anti-AFP antibody. The patient was diagnosed and treated with chemotherapy for a sacrococcygeal YST. Clinical follow-up on the fourth month showed that the tumor had shrunk to 4 cm in size. Laboratory follow-up data after four months showed significant improvement. Unfortunately, the patient passed away on the seventh cycle of chemotherapy due to lung and hepatic metastases.