Abstract：
BACKGROUND Fetus in fetu (FIF), or parasitic fetus, is a rare malformation that typically occurs in the retroperitoneum, but can be found in other unusual locations, such as the skull, sacrum, and mouth. The presence of a spine is necessary for diagnosis. CASE REPORT Intracranial FIFs were retrospectively studied. Abnormalities were detected in the fetal head during a 33-week prenatal examination; however, MRI could not provide more information, due to space occupation. A baby girl was born via cesarean delivery at 37 weeks, with a large head circumference. She had delays in motor skills and speech development, only able to say \"mom\". There was a large mass in the cerebral hemisphere, with a 13-cm maximum diameter, smooth boundary, and internal bone structure visible on head CT scan. Both ventricles and third ventricle had hydrops, with a fetal shape at a continuous level, along with apparent compression near the cerebral parenchyma. After performing preoperative examinations, laboratory tests, and surgical planning, craniotomy was performed on the FIF, under general anesthesia. Following complete mass resection, mouth, eye, arm, and hand shapes could be observed. The patient was unconscious after surgery and had seizures that were difficult to control. She died 12 days after surgery. Teratomas can be distinguished based on anatomy and imaging. Surgical resection is the only curative treatment and its prognosis is poor. CONCLUSIONS Intracranial FIF cases are rare and require early diagnosis and surgical treatment. Differentiating between FIF and teratoma is crucial, and monitoring alpha-fetoprotein levels after surgery can help detect recurrence.
摘要：
背景胎儿胎儿（FIF），或者寄生胎儿，是一种罕见的畸形，通常发生在腹膜后，但可以在其他不寻常的地方找到，比如头骨，骶骨,和嘴。脊柱的存在对于诊断是必要的。病例报告对颅内FIF进行了回顾性研究。在33周的产前检查中，在胎儿头部发现了异常；但是，核磁共振无法提供更多信息，由于空间占用。一名女婴在37周时通过剖腹产出生，头围大。她在运动技能和言语发育方面有延误，只能说“妈妈”。大脑半球有一个很大的肿块，最大直径为13厘米，平滑边界,头部CT扫描可见的内部骨骼结构。心室和第三脑室都有积水，具有连续水平的胎儿形状，伴随着大脑实质附近的明显压迫。在进行术前检查后，实验室测试,和手术计划，在FIF上进行了开颅手术，全身麻醉。完整的肿块切除后，嘴，眼睛,手臂,可以观察到手形。患者在手术后失去知觉，癫痫发作难以控制。她在手术后12天死亡。畸胎瘤可以根据解剖学和影像学来区分。手术切除是唯一的治疗方法，预后较差。结论颅内FIF病例很少见，需要早期诊断和手术治疗。区分FIF和畸胎瘤至关重要，手术后监测甲胎蛋白水平可以帮助检测复发。
