Daily Radiology Case

Explanation

Thyrotroph adenomas make TSH on their own without responding to feedback, so free T4 and T3 go up while TSH stays normal or high instead of dropping, which rules out Graves but not resistance to thyroid hormone. Most are macroadenomas by the time they are found because these tumors tend to grow large and invasive on their own, and patients show up either with mass effect like visual loss or with thyrotoxic symptoms and a goiter. Surgery is first line with somatostatin analogs for anything left behind, and the mistake to avoid is calling it Graves and ablating the thyroid, which can make the pituitary tumor grow.

Source: Neuropathology R, Pituitary macroadenoma - pediatric TSH-secreting. Case study, Radiopaedia.org (Accessed on 31 Jul 2026) https://doi.org/10.53347/rID-24392

Hints

• A 13-year-old girl comes to the emergency department after several months of bumping into doorframes and missing objects off to either side of her.
• Vitals show a heart rate of 112, blood pressure of 138/72, and she has warm moist skin with a fine tremor of the outstretched hands.
• Labs show a free T4 of 3.1 and free T3 of 9.8 with a TSH of 4.6 that fails to suppress, TSH receptor antibodies are negative, and the alpha subunit to TSH molar ratio is elevated.
• Sagittal MRI shows a round, well defined mass filling the sella and widening it, and the mass looks the same all the way through with no cysts or bleeding inside, and it grows up out of the sella into the suprasellar cistern.
• After contrast the mass lights up evenly throughout, it pushes the optic chiasm up and flattens it, and it reaches over toward the left cavernous sinus but does not wrap around the carotid.