Hypothalamic–pituitary axis disorders - thyrotropinoma (TSH-oma)
Description
- TSH-secreting pituitary adenoma -> central (secondary) hyperthyroidism
- The pattern: high fT4 and fT3 with a TSH that is normal or high - i.e. unsuppressed
- Normal feedback would drive TSH to <0.01
- Rarest functioning pituitary tumour
- ~2/3 are plurihormonal - co-secrete GH (acromegaly) or prolactin most often
Before you call it a TSH-oma - exclude artefact and resistance
A single unsuppressed TSH with high free hormones is far more often an assay problem than a tumour.
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