A lipoma of the corpus callosum diagnosed by CT at 7 mos and mistaken for hemorrhage in a premature infant is reported from the Medical College of Pennsylvania, Philadelphia, PA. The Apgar scores were 3 at 1 and 5 min, and the infant had hyaline membrane disease that progressed to bronchopulmonary dysplasia. Cranial ultrasound at 10 hrs demonstrated a subependymal hemorrhage with unchanged appearance at 17 days. Seizures associated with bilateral temporal polyspike and sharp-wave EEG activity were controlled with phenobarbital. His head circumference was at the 75th percentile and disproportionately large. A repeat ultrasound at 7 mos showed increased echogenicity in the midline with normal ventricles, interpreted as blood in the third ventricle with calcification. CT showed a large midline area of decreased density extending into the lateral ventricles, consistent with a lipoma of the corpus callosum and calcifications. At 18 mos the head is large and development is delayed at the 12 mo level. 
COMMENT. Blood, fat, and calcium have similar echogenicity by cranial ultrasound, and all three media are hyperechoic when compared to the moderate echogenicity of cerebral white matter, low echogenicity of gray matter, and absent echogenicity of fluid-filled ventricles or cysts. Lipomas are characterized by hyperechoic densities on cranial sonograms.