Asymmetric conjoined twins: pyopagus parasite.

Parasitic conjoined twins are rare variations of abnormal conjoined twinning. A case of asymmetric conjoined twins is presented in which the incomplete parasite was attached to the sacrococcygeal region of the normal twin (autosite). The parasitic twin had a rudimentary bony hemipelvis, both lower limbs with gross deformities of right lower limb covered with intact skin, intergluteal fold without anal orifice, partial gastro-intestinal system and a rudimentary bladder. The parasitic twin was excised on the third day of life and the normal twin was discharged. Postnatal follow-up after one month showed a healthy infant with normal growth pattern.