How should a suprasellar mass be evaluated and managed?

Management of a Suprasellar Mass

MRI with and without IV contrast using a dedicated pituitary protocol is the essential first imaging study, followed immediately by comprehensive endocrine testing and formal ophthalmologic evaluation to assess visual fields and acuity. 1

Initial Diagnostic Imaging

• Obtain high-resolution MRI of the sella with and without IV contrast using thin-section imaging (≤0.5 cm slice thickness) with pre- and post-contrast T1-weighted sequences if not already performed with a dedicated pituitary protocol 1, 2
• MRI is superior to CT for characterizing suprasellar masses, providing detailed visualization of the pituitary gland, infundibulum, optic chiasm, and cavernous sinus invasion 1, 3
• CT may be useful as a complementary study to identify calcifications (helpful in craniopharyngioma diagnosis) but should not replace MRI as the primary imaging modality 2, 3

Mandatory Concurrent Evaluations

Endocrine Assessment

• Perform comprehensive hormonal screening immediately, including: 1
  • Thyroid function tests (TSH, free T4)
  • Morning cortisol and ACTH
  • Sex hormones (LH, FSH, testosterone in men/estradiol in women)
  • Growth hormone/IGF-1
  • Prolactin level (critical to identify prolactinomas, which are managed medically rather than surgically) 1

Ophthalmologic Evaluation

• Obtain formal visual field testing and visual acuity assessment to document baseline function and identify optic chiasm compression 1, 4
• Visual symptoms occur in 58% of sellar/suprasellar masses and represent a surgical urgency 5

Differential Diagnosis Considerations

The imaging characteristics and clinical context help narrow the differential:

• Pituitary adenomas (most common): homogeneous enhancement, may have elevated prolactin from stalk compression 5
• Meningiomas: more vascularized, "dural tail" sign in one-third of cases, female predominance 6:1, mean prolactin 51.6 ng/ml when present 5
• Craniopharyngiomas: calcifications on CT, cystic components common 2, 6
• Rathke's cleft cysts: purely cystic, may coexist with pituitary microadenoma in 10% of cases 6
• Inflammatory lesions: can mimic tumors, require multidisciplinary evaluation including endocrinologic, neurologic, and ophthalmologic assessment 2

Advanced Diagnostic Testing

When to Perform Bilateral Inferior Petrosal Sinus Sampling (BIPSS)

• Perform BIPSS when: 1

  • Pituitary lesions are <6 mm on MRI
  • MRI is negative or equivocal despite biochemical evidence of pituitary hormone excess
  • Discordance exists between biochemical testing and imaging findings

• BIPSS is NOT necessary when: 2

  • A pituitary tumor ≥10 mm is detected on MRI AND dynamic testing is consistent with Cushing's disease
  • For tumors 6-9 mm, expert opinion varies, but the majority recommend BIPSS 2

Role of PET Imaging

• ¹¹C-methionine PET/CT can differentiate pituitary microadenoma from Rathke's cleft cyst when coexistence is suspected 6

Treatment Algorithm

Surgical Indications

Transsphenoidal resection is the mainstay of treatment for most sellar/suprasellar tumors except prolactinomas. 1

• Proceed urgently to surgery when: 1, 4

  • Mass effect on the optic chiasm is present (risk of permanent visual loss)
  • Documented tumor growth on interval imaging
  • Compression of the third ventricle (risk of hydrocephalus)
  • Visual symptoms are present (recovery becomes unlikely after one month postoperatively) 1

• Medical management is preferred for: 2

  • Prolactinomas (dopamine agonist therapy)
  • Inflammatory lesions (corticosteroids or immunosuppression)

Surgical Approach Selection

• Transsphenoidal approach (endoscopic or microscopic) is preferred for most sellar/suprasellar masses 1, 4
• Transcranial approaches are reserved for tumors with extensive bilateral cavernous sinus involvement or purely suprasellar location requiring inferior-to-superior viewing angle 7
• Avoid attempting complete resection of tumors enveloping major vessels or involving vital neural structures, as risks outweigh benefits 1

Critical Pitfalls to Avoid

• Do not delay surgical planning for resectable non-prolactinoma lesions causing visual symptoms, as visual recovery becomes unlikely after one month postoperatively 1
• Do not assume all sellar masses are pituitary adenomas: meningiomas account for 1% of sellar masses and are more vascularized and invasive, requiring different surgical planning 5
• Do not overlook the possibility of infection: rare infectious etiologies (e.g., Chagas' disease) can present as suprasellar masses with panhypopituitarism and rapid mortality 8
• Always obtain tissue diagnosis when the etiology is unclear, as the differential is broad and definitive diagnosis guides treatment 6, 8

Postoperative Management

Immediate Postoperative Care

• Plan for 2-day inpatient stay to monitor for complications including CSF leak, diabetes insipidus, electrolyte disturbances, and visual changes 4

Histopathological Assessment

• Obtain immunostaining for pituitary hormones and Ki-67 index, as Ki-67 ≥3% combined with local invasion predicts 25% recurrence rate 1

Surveillance Imaging

• Perform delayed surveillance imaging >3 months following transsphenoidal surgery for known subtotal resection or nonfunctioning adenomas, guided by tumor pathology and patient symptoms 2, 1

Long-term Endocrine Monitoring

• Lifelong endocrine surveillance is necessary, as hormonal deficiencies may develop or progress over time even after successful treatment 1
• Monitor for recurrence over several years due to high recurrence rates of cystic lesions and potential for malignant transformation 6