Management of a Sellar Mass on MRI

Initial Diagnostic Workup

• The American College of Radiology recommends obtaining comprehensive hormonal screening and ophthalmologic evaluation immediately, followed by high-resolution MRI with and without contrast if not already performed, to guide definitive treatment planning 1, 2
• Comprehensive endocrine testing should include thyroid function tests (TSH, free T4), morning cortisol and ACTH, sex hormones (LH, FSH, testosterone/estradiol), and growth hormone/IGF-1 2, 3

Imaging Optimization

• 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 is recommended if the initial MRI was not a dedicated pituitary protocol 1, 2, 4
• MRI is superior to CT for characterizing sellar masses, providing detailed visualization of the pituitary gland, infundibulum, optic chiasm, and cavernous sinus invasion 1, 4

Treatment Algorithm

• Transsphenoidal resection is the mainstay of treatment for most sellar tumors except prolactinomas, with complete resection being the treatment of choice when feasible 2
• Avoid attempting complete resection of tumors enveloping major vessels or involving vital neural structures, as risks outweigh benefits 2

Specialized Testing Scenarios

• Bilateral inferior petrosal sinus sampling (BIPSS) should be performed when pituitary lesions <6 mm are detected, MRI is negative/equivocal, or there is discordance between biochemical testing and imaging 5
• Venous sampling of the cavernous sinuses is reserved for cases with definite pituitary hormone excess, failed medical management, and negative/equivocal imaging when surgery is planned 4, 6

Critical Pitfalls to Avoid

• Delaying surgical planning for resectable non-prolactinoma lesions causing visual symptoms should be avoided, as visual recovery becomes unlikely after one month postoperatively 2
• Lifelong endocrine surveillance is necessary, as hormonal deficiencies may develop or progress over time even after successful treatment 2

Postoperative Management

• Histopathological assessment including immunostaining for pituitary hormones and Ki-67 should be obtained, as Ki-67 ≥3% combined with local invasion predicts 25% recurrence rate in pediatric cases 2
• Delayed surveillance imaging >3 months following transsphenoidal surgery is recommended for known subtotal resection or nonfunctioning adenomas, guided by tumor pathology and patient symptoms 7