PMC9271968_01
(A) Cranial CT, without contrast, axial cut, evidencing subgaleal hypoattenuating formation in the frontal region, noting in the same plane, but in intracranial and extra-axial situation, hypoattenuating lesion with expansive character associated with irregularities in the contours of the inner table of the adjacent frontal bone. (B) bone window, in the same plane of subgaleal and extra-axial lesions, evidencing in the frontal bone, especially in the internal table lytic destruction with bone discontinuity.
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F1
CT scan of the skull was performed, which showed an expansive hypodense lesion in the frontal region with intracranial extension associated with perilesional edema (Figure 1), and then transferred to the neurosurgery department with suspicion that the identified expansive formation would have neoplastic origin.
(A) Skull CT, without contrast, axial section, evidencing frontal extra-axial lesion, in left paramedian situation and hypoattenuation in the white matter of the left frontal lobe; (B) brain MRI, T2/FLAIR, axial, shows better the extra-axial expansive formation, located in the left anterior frontal pole, rounded, with apparent capsule, promoting compressive effect on the adjacent parenchyma, besides evidencing in adjacent frontal lobe small intraparenchymal lesion surrounded by important edema; (C) MRI of the brain, T1 after axial contrast, with important peripheral enhancement of both the extra-axial lesion (including with important enhancement of the locoregional meningeal plane) and intra-axial; (D) (DWI, axial section) evidences important central restriction of the extra-axial lesion with corresponding signal loss on the ADC Map (E) being compatible with empyema/abscess.
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F2
The patient underwent brain MRI, which revealed an expansive lesion in the frontal subcutaneous tissue, extending through a bone defect in the frontal sinus that communicated with an extra-axial nodular formation with intra-axial component and circumcision edema with important compressive effect, suggesting a complicated PET with concomitant cerebral abscess (Figure 2).
(A) Positioning for surgical approach and marking of the bicoronal incision, evidencing the protuberance of the forehead by progressive swelling. (B) Intraoperative image after craniotomy with emphasis on fistulous hole of communication with frontal sinus, enhanced.
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F3
Resected the residual abscess and capsule, a fistulous hole (Figure 3B) was verified communicating purulent contents of the frontal sinus with brain abscess.
Comparative study between MRI in axial, sagittal and coronal sections before and after the surgical approach.
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F4
MRI was performed, 28 days after surgery, and showed the surgical a marked reduction of the frontal extra-axial collection. Meningeal thickening and residual frontal abscess surround by perilesional edema were observed, as shown in the pre and postoperative comparative images in Figure 4.