Anaesthetic management of foetus in foetu: A rare entity.

Abstract

Sir, Foetus in foetu (FIF) is a congenital condition in which a malformed, parasitic foetus is located in the body of its twin. The incidence is 1 in 5,00,000 live births.[1] It was first described in the 1800s by Johann Friedrich Meckel. Less than 200 cases of foetus in foetu have been reported till now.[2] During the developmental stages, there is absence of independent circulatory systems, so the parasite undergoes the stage of primitive streak and it develops vertebral body and organ arranged around an axis differentiating it from a foetiform teratoma.[3] Teratoma is a differential diagnosis which is a type of germ cell tumour. Different organs seen in FIF are vertebral column (91%), limbs (82.5%) and central nervous system (55.8%).[4] 1 ½-year-old, 9-kg child presented with palpable mass in abdomen since birth, constipation and difficulty in passing urine since 3 months. Birth history was insignificant, child was immunised and had achieved milestones for age. General and systemic examination were normal except that a large, and painless mass of the size of a sweet lemon was felt per abdomen. Blood investigations, chest X-ray and echocardiography were normal. Beta-human chorionic gonadotropin and alpha-foetoprotein were negative. Abdominal sonography showed a retroperitoneal mass of 12×8×10 cm in the right suprarenal region extending to the right lumbar region, crossing the midline suggestive of teratoma or FIF. Computerised tomography (CT) abdomen showed a FIF in the retroperitoneal aortocaval region—a well-organised teratoma causing compression over the abdomen [Figure 1].Figure 1: CT Abdomen showing massNil by mouth status and consent was checked. Plan was general anaesthesia plus epidural analgesia. All standard American Society of Anesthesiologists (ASA) monitors attached. Pre-oxygenation was done, and premedication was given. Induction was done with intravenous (IV) propofol (2 mg/kg), IV fentanyl (2 µg/kg) and IV atracurium (0.5 mg/kg), intubated with 4.5 mm uncuffed endotracheal tube and maintained on atracurium, sevoflurane using pressure control mode. Right internal jugular vein was cannulated with 5F 8 cm triple lumen under ultrasonography guidance and fixed at 8 cm. Right radial artery was cannulated for arterial blood pressure (ABP). 19G epidural catheter was placed in left lateral position at L1-L2 space, fixed at 5 cm using saline technique. Infusion with Inj. Ropivacaine 0.2% was started at 2 ml/h and adjusted according to haemodynamics for adequate analgesia. 10F Ryles tube was inserted. Intraoperatively, it was found that the mass was adhered to the surrounding structures, inferior vena cava and aorta [Figure 2]. This led to increased blood loss during dissection causing fall in blood pressure and tachycardia. Beat-to-beat monitoring was done with ABP and central venous pressure; accordingly, fluid was replaced. Blood loss was replaced with packed red blood cells 15 ml/kg. Total fluid given was 900 ml crystalloids, blood loss was 200 ml and urine output was 300 ml. Body temperature was kept normal throughout the procedure. After 5 h duration of surgery, arterial blood gases were normal and patient was extubated uneventfully.Figure 2: Mass of foetus in foetuThe child was shifted to the paediatric intensive care unit for observation. Epidural 0.1% ropivacaine infusion was continued for analgesia and the child was discharged on day 15. The histopathology report showed FIF. FIF has been explained by two theories ‘Parasitic twin theory’ states that a normal foetus becomes enveloped inside the twin partner becoming dependent on its blood supply. As per ‘Teratoma theory’, it is a highly differentiated form of mature teratoma.[5] Conjoined twinning happens when the twinning event occurs at the primitive streak stage of development, 13–14 days after fertilisation, and is associated with the monoamniotic monochorionic type of placentation.[3] The presence of vertebral column differentiates between teratoma and FIF, and its presence was confirmed via CT abdomen in our case. FIF should be differentiated from a teratoma as teratoma has malignant potential.[6] According to Willis definition, FIF should have (a) separate vertebral column, symmetrical development around its axis, and (b) the organs should have developed in an organised manner with some degree of maturation,[3] all of which were present in our case. Meticulous preoperative optimisation, vigilant intraoperative monitoring and good post-operative care led to successful outcome of this rare and complicated case. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.