Abstract
Teratoma is a congenital neoplasm deriving from one or more embryonic layers. Fetiform teratoma is a highly differentiated rare type of teratoma. The authors present a 1-day-old neonate for a lumbar region mass, grossly appearing like an extremity. CT scan was performed showing a highly organized extremity skeleton in the lumbar region consisting of flat, long and short bones. Fetiform teratoma should be differentiated from a fetus in fetu, as the former lacks axial skeleton while it is the main feature of the latter, respectively. Both have different prognostic implications, and surgical excision is the treatment of choice.