Context: A rare presentation of hypothalamic tumors in infants and young children is profound emaciation and generalized loss of sc adipose tissue, also known as "diencephalic syndrome." Similar loss of sc fat can be observed in children with acquired generalized lipodystrophy or congenital generalized lipodystrophy. Precise diagnosis may be challenging early in the course of the disease, especially in the absence of metabolic abnormalities.
Case description: We report three males who presented with poor weight gain and generalized loss of sc fat at birth to 3 years of age consistent with generalized lipodystrophy, with subsequent development of pilocytic astrocytoma. Two of them had hypothalamic tumors, and one had a multicentric tumor with a large right parietal mass. Our patients are unique because the onset of lipodystrophy occurred 2.5 to 7.3 years before the diagnosis of brain tumor, and all of them gained body fat or weight after surgical removal and/or chemotherapy. One patient had hepatosplenomegaly and impaired glucose tolerance, and another patient had severe hyperglycemia and hypertriglyceridemia during the course of the disease. Two patients presented with central precocious puberty and advanced bone age at the chronological age of 6 years.
Conclusions: It is likely that pilocytic astrocytoma may induce generalized lipodystrophy by paraneoplastic antiadipocyte antibody formation or by excessive hormones or cytokine secretion resulting in excess lipolysis from adipocytes. We conclude that young children presenting with idiopathic acquired generalized lipodystrophy or atypical congenital generalized lipodystrophy, with or without metabolic abnormalities, should prompt investigation for brain tumors.