Foetus in foetu.

Summary A case of foetus in foetu or included twin is presented. The operative findings and the anatomical features of the foetus are described in detail. An included twin is usually a monochorionic, diamniotic, monozygotic twin of its bearer, which was included within it during development. Hence, the correct age must be the age of the host as it starts its origin and the development at the same time as a host. Clinically a foetus in foetu usually presents as anabdominal mass with or without pressure symptoms. Radiographically a foetus in foetu may be diagnosed with ease. it should be different from soft tissue mass of renal origin such as Wilm's tumour hydronephrosis. Nephroblastomas and teratomas may contain calcification but they lack the organization of a foelus in foetu. A foetus in foetu should be removed because of the danger of infection or infarction if it is allowed to remain within its host. The mass may be removed in its entirety or the sac may be evacuated and left in situ.