MEGALENCEPHALY, HYDROCEPHALUS AND CORTICAL DYSPLASIA IN SEVERE DWARFISM MIMICKING LEPRECHAUNISM

This report concerns an autopsy case of megalencephaly exhibiting a un ique combination of physical and brain malformations. A 4-year-old boy had a peculiar face, a severe reduction of subcutaneous adipose tissu e, severe growth failure and frequent hypoglycemic episodes. These cli nical features were compatible with leprechaunism; however, the absenc e of hyperinsulinemia and insulin resistance prevented the diagnosis o f leprechaunism. The autopsy disclosed complex cardiac and brain malfo rmations. Although hydrocephalus coexisted, the brain weight after com plete removal of the cerebrospinal fluid was 2260 g, which was greater than the average brain weight of normal Japanese children of the same age. The neuronal density in the cerebral cortex was decreased, while the surface area of the cerebral cortex and white matter were greater than those in an age-matched control. There was cortical dysplasia in the frontal and parietal lobes. Endocrine tests and immunohistochemic al analysis of the brain did not demonstrate any abnormalities in the hypothalamus-pituitary system. Megalencephaly can be associated with d warfism, and this case is important for consideration of the interrela tionship between neuronal proliferation and physical growth.