Palo Seetu, Mangla Mishu, Motwani Rohini, Gabbeta Spandana, Mishra Monica, Kanikaram Poojitha Kalyani
Department of Pathology and Laboratory Medicine, All India Institute of Medical Sciences, Bibinagar, Hyderabad, Telangana, India.
Department of Obstetrics and Gynaecology, All India Institute of Medical Sciences, Bibinagar, Hyderabad, India.
Pediatr Surg Int. 2025 Jun 14;41(1):170. doi: 10.1007/s00383-025-06087-7.
Fetiform teratomas are rare tumors mimicking malformed fetuses, posing diagnostic challenges especially when differentiating them from fetus-in-fetu. Fetiform teratomas result from neoplastic processes of germ cells, while fetus-in-fetu arises from aberrant embryogenesis, specifically the inclusion of a parasitic monozygotic twin. This review systematically examined 17 cases of fetiform teratoma identified through strict criteria, excluding cases with vertebral columns or long bones. A thorough search of multiple electronic databases, using the keywords 'fetus-in-fetu,' 'fetus-ex-fetus,' 'homunculus,' or 'fetiform teratoma' was conducted to identify relevant studies published till December 2024. Common locations of fetiform teratoma included the ovaries, retroperitoneum, and sacrococcygeal region, with clinical presentations varying from neonatal masses to pelvic pain in adults. Imaging typically revealed complex masses with solid-cystic components and calcifications, while histopathology demonstrated tissues from all three germ layers, including rare elements like thymic or retinal tissue. Accurate diagnosis relies on integrating imaging, histopathology, and ideally, cytogenetic studies, considered the gold standard for differentiating these entities based on genetic makeup. Surgical excision remains the primary treatment. Post-operative follow-up is recommended due to a small risk of recurrence or malignant transformation. This review underscores the need for standardized diagnostic criteria, primarily focusing on the absence of a vertebral column and long bones for fetiform teratomas. The study's limitations include the small sample size and lack of molecular or genetic data, highlighting the need for further research into the pathogenesis and genetic characteristics of these rare entities.
胎儿样畸胎瘤是一种罕见的肿瘤，形似畸形胎儿，尤其是在与胎内胎鉴别时会带来诊断挑战。胎儿样畸胎瘤由生殖细胞的肿瘤性过程形成，而胎内胎则源于异常胚胎发育，具体是包含一个寄生性单卵双胎。本综述系统检查了17例通过严格标准确定的胎儿样畸胎瘤病例，排除了有脊柱或长骨的病例。通过使用关键词“胎内胎”“胎外胎”“小人儿”或“胎儿样畸胎瘤”对多个电子数据库进行全面检索，以识别截至2024年12月发表的相关研究。胎儿样畸胎瘤的常见部位包括卵巢、腹膜后和骶尾部区域，临床表现从新生儿肿块到成人盆腔疼痛不等。影像学检查通常显示为具有实性-囊性成分和钙化的复杂肿块，而组织病理学显示来自所有三个胚层的组织，包括胸腺或视网膜组织等罕见成分。准确诊断依赖于整合影像学、组织病理学，理想情况下还包括细胞遗传学研究，细胞遗传学研究被认为是基于基因构成区分这些实体的金标准。手术切除仍然是主要治疗方法。由于存在复发或恶性转化的小风险，建议术后进行随访。本综述强调了标准化诊断标准的必要性，主要侧重于胎儿样畸胎瘤不存在脊柱和长骨。该研究的局限性包括样本量小以及缺乏分子或基因数据，这突出了对这些罕见实体的发病机制和基因特征进行进一步研究的必要性。
