FOETUS-IN-FETU, A PAEDIATRIC RARITY IN AN INFANT AT IRRUA SPECIALIST TEACHING HOSPITAL, IRRUA, NIGERIA

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A. Eighemhenrio¹, O. Owolabi¹, E. Odefiagbon¹, W. Akerele¹, S. Okogbenin², O. Dawodu³, T. Azeke⁴, E. Okogbenin⁵, A. Dongo⁶, O. Aweh⁷

1. Paediatric Surgery Unit, Department of Surgery, Irrua Specialist Teaching Hospital, Irrua ,Edo State Nigeria.
2. Department of Obstetrics and Gynecology, Irrua, Specialist Teaching Hospital Irrua, Edo State, Nigeria.
3. Department of Paediatrics, Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria
4. Department of Anatomic Pathology, Irrua Specialist Teaching Hospital, Edo State, Nigeria
5. Department of Psychiatry, Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria
6. General Surgery Unit, Department of Surgery, Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria
7. Plastic Surgery Unit, Department of Surgery, Irrua Specialist Teaching Hospital, Edo State, Nigeria

Abstract

Introduction: Fetus in fetu is a paediatric rarity. It involves the presence of a mass resembling a fetus inside the body of a child or an adult. It is described as a twin growing inside the body of the other. It can be located in different parts of the body but commonly the retroperitoneum. It is usually benign.

Case presentation: The patient was a 4 month old male infant who presented to the hospital with complaints of abdominal distention. The distention was noticed two months prior to presenting to our hospital. The distension was generalized and has been progressively increasing until presentation. There was no associated abdominal pain and no other abdominal symptoms.

Conclusion: Treatment is by complete excision for histological examination.

Keywords: Fetus-in-fetu (FIF), Twin, Retroperitoneum

Introduction

Fetus-in-fetu (or foetus in fetus) is a rare developmental abnormality in which a mass of tissue resembling a fetus forms inside the body of its twin.¹ Fetus-in-fetu has been defined as the presence of one of the twins in the body of the other. It is most frequently located in retroperitoneal area; however, it has been reported in other locations as well.² An early example of the phenomenon was described in 1808 by George William Young.³ This rare congenital anomaly, has been reported around 100 times since its first definition in the nineteenth century.⁴ Clinical manifestations vary. Detection is most often in infancy, the oldest reported age being 47 years.⁵ Foetus in fetu is differentiated from the teratoma by the presence of vertebral column often with an appropriate arrangement of other organs or limbs around it. Unlike teratomas, fetus-in-fetu is a benign disorder.6 Despite the requirement of the presence of a vertebral column for diagnosis; there are reports of cases without a vertebral column.⁶ Fetus in fetu most frequently (80%) inhabits the retroperitoneal region. However, there have been few reports of FIF location in the head, sacrum, scrotum and the mouth. Different organs can be seen in foetus in fetu, including vertebral column (91%), limbs (82.5%), central nervous system (55.8%), gastrointestinal tract (45%), vessels (40%), and genitourinary tract (26.5%).6 In order to qualify as a foetus-in-fetu, one of the following characteristics must be present: a mass enclosed within a distinct sac, partially or be completed covered by skin, grossly recognizable anatomic features and attached to the host by a pedicle containing a few

We report a case of foetus-in-fetu in a 4 month old male infant who presented with abdominal distension. Preoperative diagnosis of foetus in fetu in this case was made on Magnetic Resonance Imaging, and the patient underwent exploratory laparotomy with complete excision of mass. The excised mass in a sac was proven to be foetus in fetu on the basis of gross and histopathological examination.