Malignant cervical teratoma (MCT) usually appears in newborns as an enlarging mass of the neck that causes respiratory distress, requiring prompt airway control. We report a case of MCT in an infant electively delivered at 32 weeks to prevent airway impairment. At first, the preoperative diagnosis was hygroma of the neck, and a surgical excision was performed when the newborn was 9 days old. Diagnosis was benign extragonadic immature teratoma, but it was changed in MCT when cervical metastases appeared and the alpha-fetoprotein (AFP) level increased. Subsequent surgical procedures and chemotherapy were necessary. The child has been free from disease and healthy for 7 years since the last surgery. The preoperative diagnosis of MCT is difficult because of its rarity and non-specific clinical findings. Surgical excision is required for an adequate cure and airway repair; a long-term follow-up is mandatory to promptly treat any recurrence.