[د / أحمد محمد باذيب]

Obstetric

Fetus In Fetu: A Case Report
SV Phatak, PK Kolwadkar, MS Phatak

Ind J Radiol Imag 2003 13:1:93-94

Key Words: Fetus in Fetu, teratoma
INTRODUCTION

Fetus in fetu is a surgico pathological curiosity, wherein a vertebrate fetus is included within the abdomen of its partner. Masses containing bones, cartilage, teeth, central nervous system tissue, fat and muscle may be found in the abdomen of newborns and children termed `Teratomas'. They are defined as fetus in fetu if there is a recognized trunk and limbs, seemingly an abortive twinning. Although rare they should be removed because of potential effect on normal renal function and slight malignant potential. [1]

Fig 1 a: Radiograph of abdomen AP showing fetal parts skull and limb bones.
Fig 1 b: Radiograph of abdomen lateral showing fetal parts skull and teeth

Fetus in fetu is a term coined by Meckel in the early nineteenth century. It is an extremely rare condition estimated to occur once in 500,000 deliveries [2]

Case Report

A nine-year old girl presented with distension of the abdomen. On physical examination a large lump in the abdomen was found. Radiology of the abdomen (Fig. 1a, 1b) showed identifiable fetal parts like skull, teeth, and limb bones. Diagnosis of Fetus in fetu was given. At surgery the mass was removed from the retroperitoneum . A radiograph of the surgical specimen (Fig. 2) was also taken which clearly showed a skull, vertebrae, and malformed upper and lower limbs.

Fig 2: Radiograph of the surgical specimen showing fetal parts skull, spine and malformed upper and lower limbs

DISCUSSION

Fetus in fetu is a very rare condition in which a malformed parasitic twin is found inside the body of its partner as an abdominal fetiform calcified mass. They are typically located in the retro-peritoneum. Symptoms relate to the mass effect. It represents an abortive attempt of identical twinning where one fetus (the parasite) is drawn to the abdominal cavity of the host fetus (the auto site) in early intrauterine life and is attached retroperitoneally with blood supply to the former supplied by the host superior mesenteric vessels [1]. There exists much controversy whether a fetus in fetu is a well-formed teratoma (tumor composed of three germ layers) or not. The distinction between the two is based on the "willis criteria" which stress on the development of an axial skeleton with vertebral axis (having passed through the primitive streak stage) and an appropriate arrangement of other organs and limbs with respect to the axis. To be called fetus in fetu the mass must demonstrate true organogenesis [3]. Non-visualization of vertebral axis on radiography or CT Scan does not exclude fetus in fetu as the pathologist can see it. Fetu masses show varying degrees of organ system differentiation and deformity. Symmetric arrangement with respect to a vertebral axis is required for diagnosis. The masses are often enclosed within membranes resembling amnion [4] Short umbilical cord like structure attached to the mass have been described in several reports [5] Frequently vascular anastomoses with host vessels are identified. [6] The fetus is usually single but multiple fetuses [4] up to five have been reported. The weight of the fetus reported varies from 13 Gms. to 1.8 Kg. Remarkably confirmation of heart tissue is not mentioned in this case) Absence of independent circulatory system could account for fetal growth retardation in all cases. [7] Brain tissue and intestine were detected in half the cases, other uncommon organs reported are thyroid, parathyroid, pancreas, spleen, kidney, adrenal, testis, ovaries, urinary bladder, tongue, salivary glands, lymphnodes, trachea, and teeth. [7]

REFERENCES

1. John caffey retroperitoneal teratomas In Pediatric X ray diagnosis volume II, seventh edition yearbook medical publishers 1978:1805
   
   
2. Carles D, Alberti EM, Serville F etal: Fetus in fetu and acardiac monster: can the similar patterns of these two malformations be explained by a common morphological mechanism? Arch Anat cytol pathol 1991; 39:77-82
   
   
3. Hopkins KL, Dickson PK, Ball TT, Ricketts RR, O'shea PA, Abramowsky CR: fetus in fetu with malignant Recurrence. J. Pediatr. Surg 1997; 32 (10): 1476-9
   
   
4. Eng HL, Chuang JH, Lee TY etal: Fetus in fetu a case report and review of literature J Paediatr Surg 1989; 24:296-299
   
   
5. Grosfeld JL, Stepita DS, Nance WF etal: fetus in fetu an unusual cause for abdominal mass in infancy Ann Surg 1974; 180:80-84
   
   
6. Sutherland SF, Singh S: Fetus in fetu Paediatr sur Int 1988; 3:368-372
   
   
7. C.L. Thakral, DC Maji, MJ sajwani Fetus in fetu: a case report and review of the literature J Pediatr Surg 1998; 33:1432-1434