Diagnostic approach in children with unusual symptoms of acquired hypothyroidism. When to look for pituitary hyperplasia?

Background: Pituitary hyperplasia secondary to primary longstanding hypothyroidism has been reported in the literature in adults and rarely in children. Methods: Here we present the clinical presentation and diagnostic procedures in eight children with pituitary hyperplasia due to autoimmune thyroiditis, highlighting common findings, such as growth delay, fatigue or gaining weight, but also exceptional findings such as pericardial effusion, rhabdomyolysis, isolated hypertrichosis, and Van Wyk-Grumbach syndrome, which have rarely or never been described. Results and conclusions: Surprisingly no thyroid enlargement was detected. We discuss the unusual presenting signs of autoimmune thyroiditis that should raise the suspicion of pituitary hyperplasia. We suggest that a more elaborate clinical assessment and even modification of the diagnostic approach to autoimmune thyroiditis is needed in order to avoid its serious complications.