Pituitary region masses include lesions in the sella turcica, suprasellar cistern, parasellar region include cavernous sinuses, and basisphenoid/clivus. Several mnemonics have been popularized, including SATCHMO.
A more comprehensive list includes the following, along with differentiating features:
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tumors
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intrasellar
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pituitary neuroendocrine tumor (PitNET) (commonest in adults)
pituitary macroadenoma: ≥10 mm, sellar and suprasellar extension sometimes with snowman sign, remodeling of the sella
pituitary microadenoma: <10 mm, confined to the pituitary gland/sella, delayed/lower enhancement compared to the remaining gland
metastatic PitNET (pituitary carcinoma): rare, spread elsewhere in the CNS or body
pituicytoma: arise from the neurohypophysis and infundibulum, indolent, often absent pituitary bright spot, T2 hypo-isointense with prominent flow voids
granular cell tumor: arise from the posterior pituitary and infundibulum, can be indistinguishable from pituicytoma but often heterogeneously enhancing, hyperdense on CT
spindle cell oncocytoma: indistinguishable from macroadenoma, shows intense and early heterogenous enhancement
pituitary metastases: from breast, lung, kidney, gastrointestinal tract and nasopharynx 3 : involve the pituitary gland (grows rapidly: normal size pituitary fossa, osseous destruction) or the infundibulum (can have an absent bright spot)
pituitary lymphoma: rare, vivid possibly heterogenous enhancement, restricts diffusion
pituitary blastoma: rare, infants and young children
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suprasellar/parasellar
meningioma: homogeneously enhancing, dural tail, hyperostosis, can narrow cavernous ICA
craniopharyngioma (adamantinomatous or papillary): heterogeneously enhancing sellar/suprasellar mass with cystic areas and calcifications, separate from a normal pituitary gland
hypothalamic/optic chiasmatic astrocytoma/glioma: T2 hyperintense, variable enhancement, often associated with neurofibromatosis type 1
hamartoma of tuber cinereum: follows grey matter on all sequences, gelastic seizures, precocious puberty 3
germinoma: hypercellular tumor (low ADC, hyperdense on CT), commonly in younger patients <20 years of age
dermoid/epidermoid/teratoma: restrict diffusion (epidermoid), incomplete FLAIR suppression (epidermoid)
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sphenoid/clival
chordoma: T2 hyperintense, commonly in patients from 20-40, arise from the clivus
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cellular infiltrates
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Langerhans cell histiocytosis (most common)
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hypophysitis including infundibuloneurohypophysitis
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other lesions
berry aneurysm: parasellar/suprasellar, flow void, pulsation artifact, may be peripherally calcified
Rathke cleft cyst: intrasellar, non-enhancing cystic lesion, cyst with a dot sign
lipoma: suprasellar, fat signal lesion
mucocoele: centered in the sphenoid sinus, no solid enhancement
pituitary abscess: peripheral enhancing cystic lesion that restricts diffusion
pituitary stone: low signal, enlarged sella turcica
See also
It is also helpful to consider differentials narrowed by pattern of MRI appearance.