statdx/docs_md/articles/sella-pituitary-normal-variants_ad280a2d-6df3-4f2d-a195-623332ca7634.md

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Sella/Pituitary Normal Variants	ad280a2d-6df3-4f2d-a195-623332ca7634	key value 318f80ab-6abb-4067-a809-2ebdaa5a30c9 Kalen Riley, MD, MBA key value 5cff4116-3654-4b3a-bb75-5ebe0b8c9850 Anne G. Osborn, MD, FACR key value 8d5254e9-8dda-478b-8f08-bdee97a32c79 Karen L. Salzman, MD, FACR	name slug treeNodeId Brain brain 6d8829f1-14d7-45af-8675-255189aa526a name slug treeNodeId Differential Diagnosis differential-diagnosis a7fdd139-664e-4bb8-8d18-400e4733ff60 name slug treeNodeId Sella/Juxtasellar, Pineal Region sellajuxtasellar-pineal-region 5e38b9c1-3137-47e3-aa83-1fc82cb4099a name slug treeNodeId Anatomically Based Differentials anatomically-based-differentials 7a51b2ca-8fee-4c16-aff3-b7189f68ea60 name slug treeNodeId Sella/Pituitary Normal Variants sellapituitary-normal-variants null	Brain	6f83a5f1-4d99-417f-bafe-faba264f4b2e	16	01/26/23	Sella/Pituitary Normal Variants	Brain, Differential Diagnosis, Sella/Juxtasellar, Pineal Region, Anatomically Based Differentials, Sella/Pituitary Normal Variants	Sella/Pituitary Normal Variants | STATdx	Sella/Pituitary Normal Variants	DDX	true	Brain Differential Diagnosis Sella/Juxtasellar, Pineal Region Anatomically Based Differentials Sella/Pituitary Normal Variants

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title: "Sella/Pituitary Normal Variants" docid: "ad280a2d-6df3-4f2d-a195-623332ca7634" authors:

• key: "318f80ab-6abb-4067-a809-2ebdaa5a30c9" value: "Kalen Riley, MD, MBA"
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ESSENTIAL INFORMATION

• Key Differential Diagnosis Issues

  • Prior to evaluating sella/pituitary, essential to know patient age, sex - Maximum height varies with age, sex - Children: 6 mm - Males, postmenopausal females: 8 mm - Young females: 10 mm; up to 12 mm may be normal - Pregnant/lactating females: 12 mm; up to 14 mm may be normal

• Helpful Clues for Common Diagnoses

  • Pituitary Hyperplasia (Physiologic) - Enlarged pituitary gland - 10-15 mm, convex upward margin - Enhances strongly, uniformly - Indistinguishable from pathologic hyperplasia from end-organ failure or neuroendocrine tumor - May be indistinguishable from macroadenoma, lymphocytic hypophysitis - Beware: Macroadenoma-appearing pituitary in young male patients may be physiologic hyperplasia, not tumor
  • Pituitary "Incidentaloma" - Pituitary lesions in 15-20% of asymptomatic patients - Cystic changes common, may be transient - May represent incidental nonfunctional microadenoma, Rathke cleft cyst, or pars intermedia cyst
  • "Empty" Sella - Rarely (if ever) truly empty, more often partially empty - Intrasellar CSF, pituitary gland flattened against sellar floor - Primary "empty" sella - Considered normal variant - Usually asymptomatic, incidental finding - 5-10% prevalence - Peak age: 40-49 years; 4:1 female predominance - Secondary "empty" sella - Surgery, radiation, bromocriptine therapy - Sheehan syndrome (postpartum pituitary necrosis) - Commonly associated with idiopathic intracranial hypertension

• Helpful Clues for Less Common Diagnoses

  • "Bright" Pituitary Gland - Neonate: Adenohypophysis large, hyperintense on T1 MR - Size, signal ↓ during first 6 weeks
  • Absent Posterior Pituitary "Bright Spot" - Neurohypophysis normally has T1 shortening - Found in up to 20% of normal patients - Commonly absent in central diabetes insipidus - Consider Langerhans cell histiocytosis, germinoma - May be associated with pituitary hypoplasia, look for ectopic posterior bright spot
  • Small Sella Turcica - Small or shallow bony sella can be normal - Causes pituitary gland to protrude upward

References

Selected References

1. Lubomirsky B et al: Sellar, suprasellar, and parasellar masses: imaging features and neurosurgical approaches. Neuroradiol J. 35(3):269-23, 2022
2. Shih RY et al: Primary tumors of the pituitary gland: radiologic-pathologic correlation. Radiographics. 41(7):2029-46, 2021
3. Go JL et al: Imaging of the sella and parasellar region. Radiol Clin North Am. 55(1):83-101, 2017
4. Seeburg DP et al: Imaging of the sella and parasellar region in the pediatric population. Neuroimaging Clin N Am. 27(1):99-121, 2017
5. Vasilev V et al: Management of endocrine disease: pituitary 'incidentaloma': neuroradiological assessment and differential diagnosis. Eur J Endocrinol. 175(4):R171-84, 2016
6. Sioshansi PC et al: considering the ectopic pituitary gland in evaluation of the nasopharyngeal mass. JAMA Otolaryngol Head Neck Surg. 141(7):649-53, 2015
7. Ranganathan S et al: Magnetic resonance imaging finding of empty sella in obesity related idiopathic intracranial hypertension is associated with enlarged sella turcica. Neuroradiology. 55(8):955-61, 2013
8. Hess CP et al: Imaging the pituitary and parasellar region. Neurosurg Clin N Am. 23(4):529-42, 2012

Images

Selected Images

Pituitary Hyperplasia (Physiologic) Sagittal T1 MR in a young, postpartum, lactating female shows an upwardly bulging pituitary gland related to physiologic pituitary hyperplasia with the gland measuring almost 12 mm in height. Physiologic hyperplasia is most common in young, menstruating females and postpartum/lactating women.

Pituitary Hyperplasia (Physiologic) Sagittal T1 MR in a young, postpartum, lactating female shows an upwardly bulging pituitary gland related to physiologic pituitary hyperplasia with the gland measuring almost 12 mm in height. Physiologic hyperplasia is most common in young, menstruating females and postpartum/lactating women.

Pituitary "Incidentaloma" Coronal T2 MR in an asymptomatic adult shows a hyperintense pituitary cyst , possibly a small Rathke cleft cyst or nonfunctioning cystic adenoma. Such findings are common at both imaging (15-20% of cases) and autopsy.

Pituitary "Incidentaloma" Coronal T1 C+ MR shows a pituitary "incidentaloma" as a small, nonenhancing lesion in the pituitary gland in an asymptomatic patient being evaluated for metastatic disease. This cyst remained stable for many years. Findings are likely related to a nonfunctioning pituitary microadenoma and requires no therapy.

"Empty" Sella Sagittal T1 MR shows marked flattening of the pituitary gland against the floor of the sella with associated enlargement of the suprasellar cistern CSF space in this young adult.

"Bright" Pituitary Gland Sagittal T1 MR in a newborn shows a large, hyperintense adenohypophysis , a normal finding.

Absent Posterior Pituitary "Bright Spot" Coronal T1 MR shows an ectopic posterior pituitary bright spot. The posterior pituitary gland is located at the median eminence of the hypothalamus in between the normal optic tracts . No normal infundibulum is seen in this patient. The median eminence is the typical location for an ectopic posterior pituitary gland. These patients often have short stature and midline CNS anomalies.

Small Sella Turcica Sagittal T1 C+ MR shows a small, shallow sella turcica . This causes the normal-sized pituitary gland to protrude superiorly, mimicking a macroadenoma. The overall height of the pituitary gland was normal at 10 mm in this young patient.

Paramedian ("Kissing") Internal Carotid Arteries Axial T1 MR shows the flow voids of both cavernous internal carotid arteries, which curve much more medially than usual . "Kissing carotids" are normal variants. The pituitary gland often appears enlarged in these patients given the decreased transverse dimension of the pituitary.

Additional Images

Pituitary Hyperplasia (Physiologic) Coronal T1 C+ MR in a young, postpartum, lactating female shows an upwardly bulging pituitary gland . Physiologic hyperplasia with gland measured almost 12 mm in height.

Pituitary Hyperplasia (Physiologic) Sagittal T1 C+ MR shows physiologic enlargement of the pituitary gland in a young, asymptomatic patient.

Pituitary Hyperplasia (Physiologic) Coronal T1 C+ MR in a young, menstruating female shows slight, inhomogeneous enhancement in this gland with mild upward bulging . No frank intrapituitary cysts are identified; the mild inhomogeneity in enhancement is normal.

Pituitary "Incidentaloma" Sagittal T1 C+ MR in an asymptomatic adult shows a nonenhancing pituitary cyst , possibly a small Rathke cleft cyst. Such findings are common at both imaging (15-20% of cases) and autopsy.

Pituitary "Incidentaloma" Coronal CECT in an asymptomatic patient shows a nonenhancing, hypodense focus in the pituitary gland. This lesion is likely related to a nonneoplastic pituitary cyst or a nonfunctioning microadenoma.

"Empty" Sella Sagittal T1 MR shows the expected findings of a secondary empty sella after transsphenoidal hypophysectomy. The enlarged sella is mostly filled with CSF .

Small Sella Turcica Sagittal T1 MR shows a small, shallow sella and pituitary in a patient with Kallmann syndrome with hypopituitarism. Small sella also occurs as a normal variant, indistinguishable on imaging alone.

Small Sella Turcica Coronal T1 C+ MR shows a flat, shallow sella turcica causing upward bulging of the pituitary gland . Gland height measured 9 mm, normal in this young woman.