Case discussion
01Clinical context
An adult presented with severe headache and dizziness. A sellar and parasellar mass identified on CT prompted dedicated pituitary MRI. The teaching question is how the direction of extension changes the interpretation of a large sellar lesion.
02Key imaging findings
• A sellar mass measures approximately 3.3 × 3.8 × 3.0 cm, with predominantly left-sided parasellar extension. • There is extensive bilateral cavernous sinus involvement and encasement of the cavernous internal carotid arteries, with preserved flow voids. • Inferior extension involves the sphenoid body and sinuses, with destructive bone changes. • The pituitary gland is not separately identifiable; the stalk is displaced rightward. • There is no significant optic chiasmal compression despite the extensive extrasellar growth.
03Diagnostic reasoning
The sellar epicentre and pattern of extension favour an invasive pituitary macroadenoma/PitNET as the leading imaging consideration. This remains an imaging interpretation rather than a histological diagnosis. Other skull-base lesions, including plasmacytoma, lymphoma and metastasis, remain differential considerations; chordoma is less favoured if the epicentre is sellar. The useful distinction is between size and direction: lateral and inferior growth can involve the cavernous sinuses and skull base without substantial upward compression of the optic chiasm. Preserved carotid flow voids should be reported as an imaging observation, not treated as proof of normal vascular function. Endocrine findings, histopathology and subsequent clinical outcome were not supplied for this teaching package.
04Questions for clinical practice
Does limited chiasmal compression mean limited local extension?
No. This case demonstrates extensive lateral and inferior involvement despite no significant optic chiasmal compression.
Is the lesion histologically confirmed as a pituitary tumour?
No histopathological result was supplied. An invasive pituitary macroadenoma/PitNET is the leading imaging consideration.
Does this case establish pituitary apoplexy?
No. Severe headache warrants clinical consideration, but the supplied material does not establish haemorrhage or infarction within the lesion.
What is the central teaching point?
Map the direction of growth and relationships to nearby structures, rather than relying on maximum diameter alone.
05Teaching point
Map the direction of growth, not just the maximum diameter. In an invasive sellar lesion, cavernous sinus relationships, carotid encasement and inferior skull-base extension can be the decisive planning findings even when chiasmal compression is not significant.
Shown for education. De-identified — no identifiable patient data. A radiology report is a specialist opinion and must be read with the full clinical context by the treating physician.