Fetus in Fetu in an Adult Female and Brief Review of Literature

Abstract

Fetus in fetu (FIF) is a very rare condition in which malformed fetus is found within the body of a living twin, most commonly within the retroperitoneum. It is a parasitic fetal twin of a diamniotic, monozygotic type. It should be differentiated from teratoma by the presence of organized vertebral column and appropriately arranged other organs or limbs around it. There is no such axial arrangement in teratoma, which has also got definite malignant potential. We report a case of FIF in a 21-year-old lady who presented late with nonspecific abdominal symptoms. Preoperative diagnosis of FIF in this case was made on computed tomography, and the patient underwent exploratory laparotomy with complete excision of mass. The excised mass in a sac was proven to be FIF on the basis of gross and histopathological examination. Surgical excision is the ideal treatment even teratoma being the differential diagnosis.

Figure 1

Abdominal computed tomography shows a large heterogeneous retroperitoneal mass with cystic, calcified, soft tissue and lipomatous components (a). Large cystic component (b). Well-formed vertebral body with surrounding lipomatous tissue (c). Well-formed ribs and long bone (d). Inferior displacement of the right kidney by mass.

Figure 2

Three-dimensional reconstruction CT image showing bony outlines of fetus in fetu.

Figure 3

(a, b) Gross postoperative specimens showing heterogeneous soft tissue mass containing fatty areas and bony and cartilaginous tissues.

Figure 4

(a) Microscopic section showing well-formed cartilaginous tissue (H and E, ×100). (b) Microscopic section showing well-formed skeletal muscle tissues (H and E, ×100).