What is a partially empty sella?

Partially Empty Sella Syndrome: Diagnosis and Management

A partially empty sella is a condition where the sella turcica (the bony structure that houses the pituitary gland) is partly filled with cerebrospinal fluid, causing the pituitary gland to be flattened against the sellar floor. This condition can be either primary (idiopathic) or secondary to previous pituitary pathology or treatment 1.

Pathophysiology and Classification

Partially empty sella occurs when cerebrospinal fluid from the subarachnoid space herniates into the sella turcica, causing variable degrees of pituitary gland flattening 2. It can be classified as:

• Primary partially empty sella: Occurs without any history of previous pituitary disease, surgery, or radiation therapy. It's considered an anatomical variation that may be associated with idiopathic intracranial hypertension 2.

• Secondary partially empty sella: Results from previous treatment of pituitary tumors (surgery, medication, radiation), spontaneous necrosis of pituitary adenomas, infectious processes, autoimmune diseases, or brain trauma 2, 3.

Diagnostic Imaging

• MRI with high-resolution pituitary protocol is the gold standard for diagnosis 1. It provides detailed visualization of:

  • Pituitary gland flattening against the sellar floor
  • Pituitary stalk position
  • Optic chiasm
  • Herniation of subarachnoid space into the sella turcica

• CT scan may be used if MRI is contraindicated, though it's less sensitive for detecting pituitary abnormalities 1. CT is useful for evaluating bony structures of the sella.

Clinical Presentation

Most cases of partially empty sella are asymptomatic and discovered incidentally on imaging studies 4. However, when symptomatic (empty sella syndrome), patients may present with:

• Headaches
• Hormonal disturbances
• Visual disturbances
• Non-traumatic CSF rhinorrhea (rare)
• Obesity (in some cases) 4

Hormonal Assessment

Up to 40% of patients with empty sella syndrome may have at least one hormone deficiency 1, with some studies suggesting rates as high as 52% 5. A comprehensive hormonal evaluation should include:

• Growth hormone
• Thyroid function (free T4)
• Adrenal function (fasting cortisol)
• Gonadal hormones (estradiol or testosterone)
• Prolactin 1, 5

Management

1. Asymptomatic cases:

   • No specific treatment required
   • Periodic follow-up recommended 4

2. Hormonal deficiencies:

   • Hormone replacement therapy based on specific deficiencies:
     • Levothyroxine for hypothyroidism
     • Cortisone acetate for hypoadrenalism
     • Growth hormone replacement if deficient
     • Sex hormone replacement for hypogonadism 1

3. Surgical intervention is indicated for:

   • CSF rhinorrhea
   • Progressive visual disturbances
   • Severe increased intracranial pressure 4, 6

   When surgery is required, endoscopic transsphenoidal approaches may be used to elevate the sella with various materials 6.

Important Clinical Considerations

• Avoid assuming all empty sella cases are benign incidental findings as up to 30% of patients may have hypopituitarism requiring treatment 1.

• Distinguish between primary and secondary empty sella as the underlying cause of secondary empty sella requires specific attention 1.

• A multidisciplinary approach involving endocrinology, neurology, and ophthalmology is recommended for proper diagnosis, management, and follow-up 2.

• The discrepancy between reported high prevalence of pituitary insufficiency in clinical studies versus lower rates in epidemiological studies suggests possible selection bias in published literature 5.