Fetus in Fetu ... A Rare Case Report ! !

Fetus in fetu is a rare congenital anomaly, commonly of monozygotic twin, in which one fetus grows inside another fetus. It is a parasitic twin, usually presents as an abdominal mass. Most common site is retro peritoneum but it can present anywhere. It should be differentiated from teratoma which has no axial arrangement and has got definite malignant potential. Different imaging modalities can help in diagnosis. Complete excision is curative. Here we present a case of fetus in fetu which was diagnosed in antenatal period. After delivery diagnosis confirmed and complete surgical excision done. Case Report: A 30-year-old primigravida, presented to the O&G OPD at 36 weeks gestation for routine antenatal check up. Her USG showed a fetus of 36weeks gestation with cephalic presentation , AFI 10,placenta fundal with a well defined solid cystic lesion of 6.8 x 5.3cm seen in left suprarenal area of fetus along with multiple well formed bony structures like femur and pelvic bone within the solid component. No significant vascularity was seen. Provisional diagnosis of fetus in fetu was made .On routine blood investigation she was found to be anaemic with peripheral smear showing microcytic hypochromic anaemia. She was sickling +ve. There was no history of any maternal illness during pregnancy, no history of any radiation or drug intake during pregnancy. She was planned for elective caesarean section keeping blood ready. Intraoperative period was uneventful.She delivered a male baby which was immediately handed over to paediatrician. Baby was kept under observation. X ray abdomen showed a soft tissue mass in left renal area with areas of irregular calcification, displacing bowel loops to right.USG abdomen showed a left suprarenal mass with a provisional diagnosis of fetus in fetu. CT scan showed a suprarenal mass of 7x 6.7 x 6.8cm with irregular calcification displacing spleen anteriorly and left kidney inferiorly with no lymphadenopathy. Laparotomy was done by left upper transverse incision .A cystic lesion was noted in the left retroperitoneum with structures resembling thigh, leg and bones of lower limb. Mass was displacing the left kidney downwards . Mass was excised, and sent for HP study. Biopsy revealed brain like tissues, limbs and gut like structures. Diagnosis of fetus in fetu was