Lumbosacral lipomas: in utero diagnosis and prognosis.

INTRODUCTION: For the purposes of prenatal counselling and prognostication, it is essential to keep in mind the key diagnostic criteria allowing recognition of the diverse forms of spinal dysraphism. DIAGNOSIS: It is most crucial not to confuse lipomas and myelomeningoceles, the former carrying a usually favourable prognosis, while the latter a high risk of serious neurological deficits. In our experience, these two conditions can be clearly distinguished on prenatal ultrasound and by fetal biology. Lipomas are skin-covered, which explains the normality of the amniotic fluid and probably that of the intracranial content (no Chiari, no hydrocephalus). These features are distinct from those observed in the case of myelomeningoceles. The distinction between a lipoma and a meningocele is more difficult. The prenatal ultrasound presentation of many lipomas actually resembles that of a meningocele. In a few cases, the diagnosis of lipoma can, however, be suspected by the presence of an abnormally thick skin covering and intradural echoic structures that evoke a low-lying cord.
CONCLUSIONS: However, the consequences of confusing a lipoma and most of the other types of occult dysraphism are minimal. Most of these lesions carry a favourable outcome.