medwireNews: A large study confirms that craniopharyngioma (CP) should be considered in children with failure to thrive.

The researchers note, however, that diencephalic syndrome (failure to thrive due to tumour located in the diencephalon) is a rare manifestation of CP; it occurred in just 21 (4.3%) of 485 patients studied.

These 21 patients all had a body mass index (BMI) standard deviation score (SDS) below –2, and 11 were found to have hypothalamic involvement by the tumour. Of the remaining patients, three did not have hypothalamic involvement, three were not evaluable for this factor, and four patients had alternative explanations for failure to thrive (prematurity or congenital heart failure).

All 11 children with hypothalamic involvement had symptoms of increased intracranial pressure, such as headache and vomiting, but failure to thrive was the trigger for investigation in six of the children.

The first symptoms of failure to thrive appeared at a median age of 5 years, which the researchers say is similar to the age at which the obesity, the more typical presentation of CP with hypothalamic involvement, occurs. CP itself was diagnosed at a median of 8.3 years.

“Clearly, the damage of hypothalamic structures has impact on weight development”, say Hermann Müller (Klinikum Oldenburg, Germany) and study co-authors.

All the children underwent surgery, with or without irradiation. During up to 12 years of follow-up, the researchers found that underweight at presentation did not protect against later obesity. In the whole cohort, patients who were underweight at presentation gained weight in a similar fashion to those who were of normal weight at CP diagnosis, with both groups eventually attaining a similar weight to those who were obese at diagnosis, with a median BMI SDS of +3.98.

So despite their initial failure to thrive, these patients will “eventually develop obesity and are at high risk for obesity-related comorbidities”, writes the team in the Journal of Clinical Endocrinology & Metabolism.

The researchers also examined tumour properties on magnetic resonance imaging (MRI) scans, finding that patients with diencephalic syndrome tended to have less visual tract oedema than obese patients. They also had a trend towards less infiltrative growth within the hypothalamus; rather they had a slightly higher frequency of displacement of hypothalamic structures.

“However, the high quality of MRI scans necessary to make an informed neuroradiological reference assessment was limited to only a few scans”, say Müller and team, adding that this should be a priority for future research.

By Eleanor McDermid, Senior medwireNews Reporter

J Clin Endocrinol Metab 2014; Advance online publication

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