Infection of a Rathke Cleft Cyst: A Rare Cause of Pituitary Abscess

Secondary hypophysitis associated with Rathke's cleft cyst resembling a pituitary abscess

Background

Although rare, cases of hypophysitis resembling a pituitary abscess (PA) have been reported. Differential diagnosis between hypophysitis and PA is crucial as the two diseases require different treatments.

Case Description

A 38-year-old woman with headaches underwent head magnetic resonance imaging (MRI), which revealed an 11-mm mass lesion in the sella turcica. Due to breastfeeding, contrast-enhanced MRI was avoided. Pituitary adenomas and Rathke's cleft cyst (RCC) were suspected, and she was initially treated conservatively. Five months later, she acquired syndrome coronavirus two infections, and while the fever subsided with acetaminophen, the headache persisted. One month later, the headache worsened, followed by fever and diabetes insipidus. MRI revealed a pituitary cystic mass with ring-shaped contrast enhancement on T1-weighted MRI and increased signal intensity on diffusion-weighted imaging (DWI). PA was suspected, and emergency endoscopic transsphenoidal surgery was performed. The microbiological examination of the yellowish-brown content drained from the cystic mass was negative. Microscopically, the cystic lesion was covered with ciliated columnar epithelium and stratified squamous epithelium, with a dense inflammatory cell infiltrate consisting mainly of lymphocytes and plasma cells observed around the cyst. This supported the diagnosis of secondary hypophysitis associated with RCC without PA.

Conclusion

We report a case of hypophysitis secondary to RCC resembling PA with ring-shaped contrast enhancement on MRI and increased signal intensity on DWI. This case emphasizes the need for cautious diagnosis of secondary hypophysitis due to RCC in individuals with MRIs and clinical manifestations resembling an abscess.

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

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.

Rathke's Cleft Cyst Abscess with a Very Unusual Course

Infected Rathke's cleft cysts (RCC) are extremely rare with only a few published cases. We report the case of a 31-year-old man who presented with headaches, visual disturbance, and hypopituitarism secondary to an infected RCC with extension of abscesses along the optic tract. Magnetic resonance imaging showed ring enhancing cystic lesions within an expanded sella with suprasellar and intraparenchymal extension. The radiological appearance suggested a high-grade optic glioma, but an endoscopic transsphenoidal biopsy revealed frank pus in the pituitary fossa, which subsequently grew Staphylococcus aureus . Pathological examination of the cyst wall showed an inflamed RCC. Following a prolonged course of intravenous antibiotics, the infection resolved and vision improved. RCC abscesses are rare and the intracranial extension of the infection in our case makes it unique.

Typing of inflammatory lesions of the pituitary

Inflammatory pituitary lesions account for 1.8% of all specimens from the German Pituitary Tumor Registry. They occure in 0.5% of the autoptical specimens and in 2.2% of the surgical cases. Women are significantly more often affected than men and are often younger when first diagnosed. In general, primary and secondary inflammation can be distinguished, with secondary types occurring more frequently (75.1%) than idiopathic inflammatory lesions (15.4%). In primary inflammation, the lymphocytic type is more common (88.5%) than the granulomatous type of hypophysitis (11.5%). The most common causes of secondary inflammation are Rathke's cleft cysts (48.6%), followed by tumors (17.4%) such as the craniopharyngioma (9.1%), adenoma (5.5%) or germinoma (2.0%). More causes are tumor-like lesions (7.1%) such as xanthogranuloma (3.5%) or Langerhans histiocytosis (3.5%), abscesses (5.5%), generalized infections (5.1%), spreaded inflammations (4.7%) and previous surgeries (4.0%). In 1.6% of all specimens the reason for the inflammation remains unclear. The described classification of hypophysitis is important for specific treatment planning after surgery.

Primary Sellar Abscesses: A Systematic Review and 2 Rare Observations

BACKGROUND

Abscesses of the chiasmatic-sellar region are quite rare and are often a result of surgical intervention, trauma, or tumor growth. Primary abscesses are extremely rare and represent a group of abscesses the occur because of internal microbial seeding. Primary abscesses are rarely reported. We present 2 clinical cases featuring primary abscesses of the chiasmal-sellar region. To put into perspective the rarity of these findings, we performed a systematic review of existing clinical reports regarding this pathology.

METHODS

A systematic review of literature was conducted to gather existing clinical reports on primary abscesses of the chiasmatic-sellar region. Two personal findings are added to the literature review, including a 13-year-old girl and a 58-year-old man who presented with chiasmal-sellar region primary abscesses. The diagnostic aspects, treatment strategy, and outcomes are discussed.

RESULTS

Both patients included in the report had positive outcome. The pediatric patient developed a recurrence of the abscess and was treated accordingly. Overall, 41 cases of primary abscesses of this region have been reported in literature, of which 6 are in children under 18 years of age. The main nonspecific clinical manifestations include headaches, visual impairment, and endocrine pathology. Acute inflammatory responses are rarely seen, despite infectious genesis. Transnasal endoscopic surgical treatment offers diagnostic and treatment advantages.

CONCLUSIONS

Proper diagnostic procedures can aid in correct treatment strategy and improve overall outcome.

Primary pituitary abscess in an adolescent female patient: case report, literature review, and operative video

PURPOSE

Primary pituitary abscesses are extraordinarily rare lesions, especially in pediatric populations, with very few cases described in the literature. Here we review this rare condition and discuss its management.

METHODS

We report a case of a previously healthy 12-year-old female patient who presented with vomiting and meningismus. We review the literature on pediatric patients presenting with pituitary abscesses and the described treatments. An operative video demonstrating our surgical technique is provided.

RESULTS

Magnetic resonance imaging of the brain revealed a rim-enhancing, diffusion-restricting sellar lesion concerning for abscess. No sinus disease or other structural cause of intracranial infection was identified. An endoscopic transsphenoidal approach was used to visualize the endonasal structures, and microscopic guidance was used for evacuation of the abscess. Purulent material was drained immediately upon entry into the lesion. Tissue cultures grew Cutibacterium acnes. Postoperatively, the patient was hypocortisolemic but otherwise endocrinologically normal. She was discharged four days later on oral hydrocortisone and intravenous ceftriaxone without any neurologic deficit.

CONCLUSION

To the best of our knowledge, this is the second report in the literature of a primary pituitary abscess due to C. acnes infection.

MRI and pathological features of Rathke cleft cysts in the sellar region

The aim of the present study was to investigate the MRI and pathological features of Rathke cleft cysts (RCC) in the sellar region. A total of 45 RCC cases were retrospectively analyzed. RCC size, location, intracyst nodules and general signals, as well as the posterior pituitary bright spot (PPBS) were analyzed using MRI-T1 weighted images (T1WI) and T2WI. The relationship between the presence of PPBS and histopathological features was additionally evaluated. On T1WI, there were 18 cases of isointense signal, 16 cases of hyperintense signal, 9 cases of hypointense signal, 1 case of heterogeneous signal and 1 case with a stratification effect, with isointense signal in the upper part and hyperintense signal in the lower part. On T2WI, there were 5 cases of isointense signal, 27 cases of hyperintense signal, 11 cases of hypointense signal and 1 case of the stratification effect. There were 10 cases of PPBS+ and 35 cases of PPBS-. There were no significant differences in the age, sex, cyst location and size between PPBS+ and PPBS- cases. However, PPBS+ cases had significantly lower inflammation than PPBS- cases. A total of 20 cases of intracystic nodules were identified on MRI scans, most of which exhibited T2 -hypointense signals. The shape of RCC nodules varied and there were 17 cases where the nodules were non-adherent to the cyst wall. The MRI signals of RCCs varied and most nodules were floating within cysts. Intracystic nodules are characteristic features of RCCs when observed by MRI and thus are of high diagnostic value. Most patients with RCC were also PPBS-, which may be associated with an increased inflammatory response.

Rathke cleft cyst masquerading as pituitary abscess: A case report

BACKGROUND

Rathke cleft cyst (RCC) is a rare cystic sellar entity, which is usually small in size and asymptomatic in most patients. RCC presenting panhypopituitarism and a cystic lesion with rim enhancement on magnetic resonance imaging is extremely rare. Therefore, it is easy to be misdiagnosed as pituitary abscess because of the similar clinical manifestations and neuroimaging changes.

CASE SUMMARY

We report a rare case of RCC masquerading as pituitary abscess clinically and radiologically with no evidence of central nervous system infection. The patient was initially suspected to be diagnosed with pituitary abscess, which was denied by the histopathological findings of RCC with no intraoperative drainage of abscess.We present an uncommon case of RCC masquerading as pituitary abscess in a 62-year-old Chinese male patient. The patient was admitted to Peking Union Medical College Hospital complaining of severe frontal pulsatile headache, visual acuity deficit, polyuria, polydipsia, and slight disturbance of consciousness. The biochemical and endocrinological examinations revealed severe hyponatremia and panhypopituitarism. Magnetic resonance imaging showed a sellar lesion with the apparent cystic change and rim enhancement. Accordingly, pituitary abscess was misdiagnosed at the beginning.The patient received hormone replacement therapy and underwent a trans-sphenoidal surgery. The surgical findings were uneventful. The histopathological examinations showed no infiltration of inflammatory cells or pus, and proved the lesion to be RCC.

CONCLUSION

Through this rare case, we aim to emphasize that the differential diagnosis of sellar lesions requires constant vigilance and that RCC may lead to clinical and radiological changes similar with pituitary abscess.