Sellar and suprasellar
| Lesion | Imaging | Pearls |
|---|---|---|
| Pituitary microadenoma (< 10 mm) | dynamic contrast‑enhanced MRI (IOC): hypoenhancing relative to the normal gland in the early phase, delayed enhancement; stalk deviation, sellar floor erosion | prolactinoma (commonest functioning), GH, ACTH (Cushing: may be tiny, petrosal sinus sampling) |
| Macroadenoma (≥ 10 mm) | snowman / figure‑of‑8 (waist at the diaphragma sellae), enlarges sella, cavernous sinus invasion (Knosp grade; > 67% ICA encasement), chiasm compression | bitemporal hemianopia; pituitary apoplexy (haemorrhage/infarct: sudden headache, visual loss) |
| Craniopharyngioma | adamantinomatous (children 5–14): cystic + solid + calcified (~90%), "machine‑oil" fluid (T1 bright); papillary (adults 40–60): solid, rarely calcified (BRAF V600E) | the "90% rule" (90% cystic, 90% calcified, 90% enhance) in children |
| Rathke cleft cyst | intrasellar/suprasellar, non‑enhancing cyst, intracystic nodule, no calcification | asymptomatic, incidental |
| Meningioma | tuberculum/diaphragma sellae, dural tail, separate from the gland | — |
| Aneurysm | flow void, laminated thrombus, pulsation artefact; CTA/MRA | never biopsy a "sellar mass" without excluding aneurysm |
| Germinoma | suprasellar + pineal (synchronous), DI in children | — |
| Hypothalamic/optic glioma | NF1 | — |
| Lymphocytic hypophysitis | thickened stalk, peripartum women | — |