Endocrine Abstracts

Introduction: Generalised lipodystrophy is clinically characterised by lipoatrophy, hepatomegaly, hypertriglyceridemia, insulin resistance and acromegaloid features. It is recognised that diencephalic syndrome is a rare presentation of hypothalamic tumours in infants and young children. Children with this disorder have profound emaciation and generalised loss of subcutaneous fat, growth acceleration, hyperkinesia and euphoria. Hypothalamic tumours, particularly pilocytic astrocytomas have also been recently reported to be associated with generalised lipodystrophy, a clinical picture that may be very similar to the diencephalic syndrome.

Case Report: We present an 18 month old boy that was referred with significant failure to thrive from the age of 6 months and clinical features suggestive of generalised lipodystrophy. Despite having good appetite and a hyper caloric diet (1800 calories per day), his weight at presentation was −5.2 SDS, height −2.1 SDS and head circumference −2.2 SDS. His examination showed generalised loss of subcutaneous fat with prominent musculature and subcutaneous veins, pale skin, triangular face and prominent forehead. He had no hepatosplenomegaly and his development and neurological examination were normal.

Investigations showed normal baseline pituitary function and normal metabolic profile with no dyslipidaemia or glucose intolerance. His liver ultrasound, however, demonstrated an 8 cm liver with diffuse fatty changes. He had a normal microarray and was negative for Russell-Silver syndrome. DNA sample was sent to the Institute of Metabolic Science in Cambridge to test for generalised congenital lipodystrophy. A brain MRI at the age of 2.5 years revealed a hypothalamic mass, currently awaiting histopathological diagnosis.

Our patient is distinct from those presenting with diencephalic syndrome because he did not have hyperkinesia or euphoria and there was evidence of fat deposition on the liver, despite loss of subcutaneous fat. Because of unexpected delays in performing the brain MRI, it is unclear if the onset of the lipodystrophy occurred prior to the development of the tumour, although unlikely in view of the tumour size.

Conclusion: Hypothalamic brain tumours should be considered in children with clinical features suggestive of generalised lipodystrophy, even without biochemical evidence metabolic abnormalities, normal pituitary function and normal neurological examination.