Abstract
Fetiform teratoma is a rare highly developed mature teratoma with organoid differentiation although it is not as developed as fetus in fetus which is the only differential diagnosis of this entity. It should be distinguished from the fetus in fetu by absence of the axial skeleton. A 6-month-old baby girl with a lumbar lump underwent ultrasonography, CT-scan and surgery. On imaging, a sac-like structure was noted in the lumbar region containing bowel segments, mesentery-like structure and few lymph nodes. The patient underwent surgery. The entire sac with its content were completely excised. Very few cases of fetiform teratoma have been reported in English literature however to the best of our knowledge lumbar fetiform teratoma has not been reported up to now. Highly developed teratoma is a diagnostic dilemma as it resembles fetus in fetu. The absence of a spinal axis differentiates this entity from the fetus in fetu.