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CT with 3D reformats..Multiple brain abscesses in the setting of a congenital sinus frontalis defect.

Study the images and decide for yourself and give your comments in the comment section

Fig.1: CT without contrast.

Fig.2: CT Bone windows with 3D reformats.

Fig.3: T1-SE-weighted axial image post IV contrast. 4 days post initial CT scan.

Fig.4: T1-SE-weighted axial image post IV contrast. 18 days post initial CT scan.

Fig.5: T1-SE-weighted axial image post IV contrast. 2 months post antibiotics therapy and hyperbaric oxygenation.
Patient Hx

10 year-old boy with changes in behaviour for 8 days noticed by parents. Since the day before hospital admission, the boy had a fever of 39.5°C. Admission to the hospital and CT performed with the concern for brain hemorrhage.
Differential Diagnosis

* Multiple brain metastases
* Glioblastoma
* Pilocytotic astrocytoma.


Final Review

Final Diagnosis

Multiple brain abscesses in the setting of a congenital sinus frontalis defect.
Method

Noncontrast enhanced CT in brain window, bone window and 3D reformation.
Description of Findings

Image 1 (CT 1): Without contrast media (question of a brain hemorrhage!): Demonstrated are round hypodense areas in the frontal lobes bilaterally.

Image 2 (CT 2): 2 days after initial CT scan. Bone window images (upper left) and 3-D reformations (lower right) demonstrate the frontal sinuses: Evidence of a bony defect of the posterior wall of the right frontal sinus.

Image 3 (MRI 1): 4 days after initial CT scan. T1-SE-weighted axial image after IV contrast administration: Depiction of two large fluid formations with rim enhancing walls in both anterior frontal lobes. Marked meningeal enhancement, especially frontal.

Image 4 (MRI 2): 18 days after initial CT scan. T1-SE-weighted axial image after IV contrast administration: Depiction of two large fluid formations with rim enhancing walls in both anterior frontal lobes. Worsening of the surrounding edema (only shown here on T1). Persistent meningeal enhancement, especially frontally.

Image 5 (MRI 3): T1-SE weighted axial image after contrast media: 2 months after beginning therapy with antibiotics and hyperbaric oxygenation: The previously large frontal fluid formations on both sides are significantly reduced in size. Patient is asymptomatic.
Discussion

The etiology of bacterial cerebral abscesses can be hematogenic (often endocarditis), after trauma or can be due to direct extension from a neighbouring infectious process. A common cause is sinusitis with a concurring bony defect in the posterior wall of the frontal sinus (as in this case). In immune-competent patients, fungal pathogens should also be considered besides a bacterial infection.

Clinically it often starts subtly. Commonly, there is only a moderate leucocytosis. In chronic courses and a thick abscess membrane, it might be mistaken with a glioblastoma multiforme, since both changes commonly show a perifocal edema.
Authors

Roland Talanow, MD, PhD.
References

1. Talanow R, Hirsch W. Congenital frontal sinus defect complicated by multiple brain abscesses PedRad.info, 2002 Dec {Online}. URL: www.PedRad.info/?search=20021227193320
2. Giannoni C, Sulek M, Friedman EM. Intracranial complications of sinusitis: a pediatric series. Am J Rhinol. 1998 May-Jun; 12(3):173-8.
3. Lee GY, Daniel RT, Brophy BP, Reilly PL. Surgical treatment of nocardial brain abscesses. Neurosurgery. 2002 Sep; 51(3):668-71.

Notes

Several surgeries in the region of the right frontal sinus. A drainage of the abscesses was not done (reason?). After further 3 months (images not shown), only inactive scar tissue seen on the FLAIR-sequence.

URL of the original case: www.PedRad.info/?search=20021227193320