Pituitary abscess: a case report and systematic review of 488 cases

Abstract

Background Pituitary abscess (PA) is a rare condition and not well understood. We aimed to describe a case and perform a comprehensive systematic review to explore presenting symptoms, radiological findings, endocrine abnormalities and mortality. Aim To identify presenting symptoms, radiological findings, endocrinological abnormalities and predictors of mortality for PA. Methods We systematically reviewed the literature to identify all case reports of PA. Data regarding presentation, mortality, radiological findings, endocrinological abnormalities and treatment was extracted. Results We identified 488 patients from 218 articles meeting the inclusion criteria. Mortality was 5.1%, with days to presentation (OR 1.0005, 95% CI 1.0001–1.0008, p < 0.01) being the only identified independent predictor of mortality. Mortality rates have decreased over time, with cases published prior to 2000 having higher mortality rates (OR 6.92, 95% CI 2.80–17.90, p < 0.001). The most common symptom was headache (76.2%), followed by visual field defects (47.3%). Classical signs of infection were only present in 43%. The most common imaging feature on magnetic resonance imaging (MRI) was high T2 and low T1 signal of the pituitary gland with peripheral contrast enhancement. Over half (54.8%) were culture negative, with the most common bacterial organism being staphylococcus aureus (7.8%) and fungal organism being aspergillus (8.8%). The most common endocrine abnormality was hypopituitarism (41.1%), followed by diabetes insipidus (24.8%). Whilst symptoms resolved in most patients, persistent endocrine abnormalities were present in over half of patients (61.0%). Conclusion PA is associated with significant mortality, with delayed presentation increasing risk of mortality. Ongoing endocrinological abnormalities are common. Given the non-specific clinical presentation, the appearance of high T2, low T1 and peripheral contrast enhancement of the pituitary on MRI should prompt consideration of this rare disease.

Primary Pituitary Abscess: Two Case Reports

“…Prior reports have demonstrated that up to 50% of pituitary abscesses yielded negative culture results, indicating the presence of a sterile abscess. 1 9 Interestingly, a previous study found a differential rate of sterile abscesses in primary versus secondary abscesses with rates of 15% versus 35%, respectively. 8 Some surgeons attribute the high frequency of sterile abscesses to the view that those abscesses may not be abscesses at all; rather, sites of aseptic, liquefactive necrosis due to a previously infarcted pituitary gland or tumor.…”

“…In the majority of reports, headache is the most common presenting symptom of pituitary abscess with the most recent review demonstrating a frequency of 76.2%. 1 Despite being the most common symptom, however, the location of reported headaches can be variable, including bifrontal, retroorbital, and vertex headaches. 9 Due to the lack of a characteristic pattern, presence of a headache may not be a helpful tool for diagnosis of a pituitary abscess, and both clinical features, as well as laboratory results reflective of pituitary hypofunction, may be more useful to aid in diagnosis.…”

“…Less than 500 cases have been reported in the literature to date, accounting for approximately 1% of all pituitary lesions. 1 The majority of cases are considered to be primary pituitary abscesses, which are the result of infection in an otherwise healthy pituitary gland. The infection can reach the central nervous system via three primary routes: hematogenous seeding from an extracranial location (such as an upper respiratory tract infection), a direct extension from a contiguous extracranial region, or by being introduced by a previous neurosurgical procedure.…”

“…Key radiological features on magnetic resonance imaging (MRI) include hypointensity or isointensity on T1-weighted imaging, hyperintensity or isointensity on T2-weighted imaging, and rim enhancement after gadolinium-based contrast injection. 1 7 8 …”

The brain region that is least prone to abscess: pineal gland

“…The structure in question is situated in a deep region of the brain, resulting in a somewhat secluded position that offers protection against typical sources of infection. This is in contrast to the pituitary gland, which is more exposed and hence more prone to infections 3 , 4 . Pineal infections can still occur infrequently in this area for a variety of causes, such as direct extension from adjacent tissues or hematogenous dissemination.…”