Does Empty Sella Mean the Pituitary is Atrophied?
No, an empty sella does not necessarily mean the pituitary gland is atrophied—it indicates herniation of cerebrospinal fluid into the sella turcica with variable degrees of pituitary gland flattening, but the gland may retain normal or near-normal function in many cases. 1, 2
Understanding the Anatomic Finding
An empty sella is defined as a sella turcica that is completely or partly filled with cerebrospinal fluid, resulting from herniation of the subarachnoid space into the sellar region. 2 This creates compression and flattening of the pituitary gland rather than true atrophy in most cases. 2, 3
The key distinction is that "empty" refers to the radiographic appearance, not the complete absence of pituitary tissue. The gland is typically present but compressed and flattened against the floor of the sella. 2, 3
Clinical Significance and Hormonal Function
Prevalence of Pituitary Dysfunction
While the sella appears empty on imaging, pituitary function varies considerably:
- Approximately 30% of patients with empty sella demonstrate some degree of hypopituitarism upon testing, though most remain asymptomatic. 1
- The incidence of endocrine pituitary disorders (defined as at least one hormone deficit) ranges from 19% to 40% in clinical series. 3
- A pooled analysis found that 52% of patients with primary empty sella syndrome had some degree of pituitary insufficiency. 4
Why Function May Be Preserved
The majority of patients with empty sella never develop symptoms or significant hormonal dysfunction, indicating that the compressed pituitary tissue retains adequate function despite its altered appearance. 5, 3 This demonstrates that anatomic compression does not equate to functional atrophy.
Etiology Matters for Understanding the Finding
Primary Empty Sella
Primary empty sella occurs without any prior pituitary pathology and is often simply an incidental finding related to a congenitally deficient sellar diaphragm. 2 In these cases, the pituitary gland is compressed but not necessarily dysfunctional.
Secondary Empty Sella
Secondary empty sella may result from:
- Spontaneous necrosis of a previous pituitary adenoma (most common cause in clinical series) 6
- Previous surgical, pharmacologic, or radiation treatment of the sellar region 2
- Pituitary infectious or autoimmune processes 2
In secondary cases, the "empty" appearance may indeed reflect loss of pituitary tissue from the underlying pathology rather than simple compression. 6, 2
Recommended Clinical Approach
Initial Assessment
MRI using high-resolution pituitary protocols is the preferred diagnostic modality to characterize empty sella and can confirm the diagnosis even without IV contrast. 1, 7 This imaging helps distinguish between simple compression and actual tissue loss.
Hormonal Screening
Despite the variable risk of dysfunction, comprehensive hormonal screening is warranted:
- Basic hormonal screening should include thyroid function tests (TSH, free T4), morning cortisol and ACTH, sex hormones (testosterone or estradiol, FSH, LH), prolactin, and IGF-1. 7, 8
- This screening is justified because approximately 30% will have some hormonal abnormality, and identifying deficiencies (particularly cortisol and thyroid) is critical for patient safety. 1, 7
Follow-Up Strategy
- If no hormonal alterations are detected initially, careful reevaluation at 24-36 months is suggested given the low risk of progression to empty sella syndrome. 3
- Endocrinology referral is indicated if any hormonal abnormalities are detected or if symptoms suggestive of pituitary dysfunction develop. 7
Critical Pitfalls to Avoid
- Do not assume that an empty sella automatically means complete pituitary failure—many patients have normal or near-normal function. 5, 3
- Do not skip hormonal screening based on the absence of symptoms—up to 30% will have subclinical deficiencies that require treatment. 1, 7
- Do not attribute all symptoms directly to the empty sella without considering other etiologies, particularly when evaluating common complaints like headache. 7