A 43-year-old man from a remote part of India (over 1800 km from our institution), presented with a headache of 3 years duration. He was of short stature, had delayed puberty and was mentally retarded. On evaluation he was detected to have primary hypothyroidism with markedly elevated thyroid-stimulating hormone titres. A CT of the brain revealed a large sellar mass with suprasellar extension into the third ventricle causing obstructive hydrocephalus. Surgical intervention was deferred due to absence of visual impairment and the presence of gross hypothyroidism. The clinical diagnosis of congenital hypothyroidism was confirmed by the absence of radioiodine uptake in the thyroid bed. With thyroid hormone replacement therapy, the 'tumour' underwent significant reduction in size with the resolution of hydrocephalus thereby favouring a potential pituitary pseudotumour. This was an unusual situation of a giant pituitary pseudotumour detected in an adult with untreated congenital hypothyroidism.
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