Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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March 21, 2019
Pituitary Abscess
- Background
- Pituitary abscess is a rare, but potentially life threatening condition unless promptly diagnosed and treated, and it accounts for less than 1% of all pituitary diseases.
- Given the rare incidence and vague symptoms accompanying the disease, the majority of cases are diagnosed either post mortem or post operatively.
- Pituitary abscesses may occur in a normal pituitary gland in 70% of cases, or secondary to a preexisting lesion, such as craniopharyngioma, adenoma, or a Rathke cleft cyst.
- It can be due to hematogenous spread of infection or direct spread such as from meningitis or sinusitis.
- Clinical Presentation
- Patients may present with headache, anterior pituitary dysfunction, diabetes insipidus, visual disorders, dizziness, fever, and non specific signs of infection.
- Key Diagnostic Features
- On CT, there may be enlargement of the sella turcica with a round, low attenuation mass with a peripheral rim of enhancement.
- The MRI findings are a cystic sellar mass that is isointense or hypointense on T1 weighted images and isointense or hyperintense on T2 weighted images.
- After contrast administration, there is a peripheral rim of enhancement.
- The mass shows restricted diffusion.
- Differential Diagnosis
- Cystic pituitary adenoma: A cystic pituitary adenoma may mimic a pituitary abscess but should not show diffusion restriction.
- Rathke’s cleft cyst or intrasellar craniopharyngioma: Both craniopharyngiomas and Rathke’s cleft cysts may contain nodules which would help differentiate from a pituitary abscess.
- Craniopharyngiomas typically are lobulated cystic/nodular masses. They may show instrinstic T1 hypersignal. They may have peripheral contrast enhancement but should not have diffusion restriction.
- Rathke’s cleft cysts may rarely have a rim of enhancement on post contrast images but should not have diffusion restriction. They may be T1 hyperintense and may have an internal low T2 signal nodule.
- Pituitary apoplexy: Pituitary apoplexy may be indistinguishable from pituitary abscess but both would be treated surgically. Pituitary apoplexy may show heterogeneous internal signal and restricted diffusion due to blood products, and may have peripheral contrast enhancement.
- Treatment
- Surgical drainage and antibiotic therapy
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