What is partial empty sella (sella turcica)?

Partial Empty Sella: Definition, Diagnosis, and Clinical Implications

Partial empty sella is a radiographic finding characterized by herniation of cerebrospinal fluid into the sella turcica with partial compression (<50% filling) of the pituitary gland, which remains >2mm in thickness. 1 This condition occurs when the subarachnoid space extends into the sella turcica, partially compressing the pituitary gland against the sellar floor.

Types and Etiology

Partial empty sella can be classified as:

1. Primary (Spontaneous) - No identifiable cause, though often associated with:

   • Pituitary hyperfunction (75.6% of cases) 2
   • Idiopathic causes (14.6% of cases) 2

2. Secondary - Due to identifiable causes:

   • Previous pituitary surgery
   • Radiation therapy
   • Neurological causes (9.7%) including head trauma, venous sinus thrombosis, or hydrocephalus 2
   • Pituitary apoplexy with subsequent necrosis 3

Diagnostic Imaging

MRI is the gold standard for diagnosis, showing:

• Cerebrospinal fluid within the sella turcica
• Partial compression of the pituitary gland
• Pituitary thickness >2mm
• Less than 50% filling of the sella with CSF 1

CT imaging is less sensitive than MRI for detecting pituitary abnormalities 4.

Clinical Significance and Hormonal Implications

Most cases of partial empty sella are asymptomatic and discovered incidentally during imaging for unrelated conditions 5. However, clinical vigilance is important because:

• Up to 30% of patients with empty sella may demonstrate some degree of hypopituitarism upon testing 6
• Secondary adrenal insufficiency and hypogonadism are significantly more common in complete empty sella compared to partial, but still occur in partial empty sella 1
• Comprehensive hormonal evaluation is necessary as up to 40% of patients may have at least one hormone deficiency 4

Recommended Evaluation

For patients with partial empty sella, the following evaluations are recommended:

1. Endocrine Assessment:

   • Morning ACTH and cortisol
   • TSH and free T4
   • FSH, LH, estradiol (females), testosterone (males)
   • Prolactin
   • Growth hormone and IGF-1 1

2. Ophthalmologic Examination:

   • Visual field testing
   • Assessment for papilledema 4

3. Blood Pressure Measurement and assessment for symptoms of hormone deficiencies 4

Management Considerations

• Most patients with partial empty sella have a good prognosis and remain asymptomatic 5
• Hormone replacement therapy should be initiated based on specific deficiencies:
  • Levothyroxine for hypothyroidism
  • Cortisone acetate for hypoadrenalism
  • Growth hormone replacement if deficient
  • Sex hormone replacement for hypogonadism 4
• Surgical intervention is rarely necessary but may be considered in cases with progressive visual disturbances 7

Important Clinical Pitfalls

1. Overlooking hormonal deficiencies: Up to 30% of patients with hypopituitarism requiring treatment may be missed without comprehensive evaluation 4

2. Misdiagnosis: Partial empty sella may be confused with other sellar pathologies; MRI is essential for accurate diagnosis

3. Failure to recognize underlying causes: In many cases, partial empty sella is secondary to pituitary hyperfunction or neurological conditions that require specific management 2

4. Inadequate follow-up: Regular endocrine evaluation is necessary, particularly if symptoms develop over time