PMC8769470_01
Brain CT on day 1 (A) and day 7 (B) after admission. (C) Brain CT on postoperative day 1 showing hematoma disappearance and pseudoair hypoattenuation (*) estimated with lung windows (window widths of 1500). (D) Brain CT on postoperative day 5 indicating subfalcine herniation caused by the cyst in the hematoma cavity. CT: computed tomography.
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F1
Brain computed tomography (CT) revealed a subcortical hemorrhage in the right frontal lobe (hematoma volume: 35 mL) (Fig. 1A). His consciousness gradually decreased to Glasgow Coma Scale (GCS)-E2M5V3 due to brain edema (Fig. 1B). On postoperative day 1, brain CT showed pseudoair hypoattenuation, suggesting the presence of residual gelatin-thrombin matrix (Fig. 1C). Surprisingly, brain CT and magnetic resonance (MR) imaging revealed subfalcine herniation caused by the cyst in the hematoma cavity with worsening brain edema (Figs. 1D and 2A-2E).
(A-E) Brain MR imaging on postoperative day 5 demonstrating the cyst in the hematoma cavity. Diffusion-weighted image showing hyperintensity at the cyst wall (A). T1-weighted image showing isointensity (B). T2-weighted image showing hyperintensity (C). Cyst wall enhancement on axial (D) and coronal (E) MR images after gadolinium administration. (F) Intraoperative view indicating the whitish areolar tissue and fluid accumulation in the cyst. (G) Red-brown sterile fluid in the cyst. (H and I) Hematoxylin and eosin staining demonstrating eosinophilic acellular material and infiltration of inflammatory cells (H) and foam cell accumulation (I). Scale bar = 100 microm. MR: magnetic resonance.
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F2
Surprisingly, brain CT and magnetic resonance (MR) imaging revealed subfalcine herniation caused by the cyst in the hematoma cavity with worsening brain edema (Figs. 1D and 2A-2E). Red-brown sterile fluid accumulated in the hematoma cavity, and the cyst wall was composed of whitish areolar tissue (Fig. 2F-2G). Histological evaluation of the cyst wall revealed gelatin-thrombin matrix residue, inflammatory cell infiltration (Fig. 2H), and foam cell accumulation (Fig. 2I).
PMC8769470_02
Brain CT on day 1 after admission (A) and postoperative day 1 (B). (C) Brain CT on postoperative day 15 showing the cyst in the hematoma cavity. (D) Brain CT on postoperative day 25 indicating cyst shrinkage after steroid treatment. CT: computed tomography.
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F3
Brain CT revealed subcortical hemorrhage in the right frontal lobe (hematoma volume: 31 mL) (Fig. 3A). Front-parietal craniotomy and hematoma evacuation were performed on day 1 after admission (Fig. 3B). Surprisingly, brain CT (Fig. 3C) and MR imaging (Fig. 4A-4E) revealed cyst formation in the hematoma cavity with worsening brain edema. The cyst appeared to be responsive to steroid treatment on brain CT (Fig. 3D).
(A-E) Brain MR imaging on postoperative day 16 demonstrating the cyst in the hematoma cavity. Diffusion-weighted image showing hyperintensity on the cyst wall (A). T1-weighted image showing hyperintensity (B). T2-weighted image showing hyperintensity (C). Cyst wall enhancement on axial (D) and coronal (E) MR images after gadolinium administration. (F-J) Brain MR imaging on postoperative day 33 demonstrating cyst shrinkage after steroid treatment. Diffusion-weighted image (F). T1-weighted image (G). T2-weighted image (H). Axial (I) and coronal (J) MR images after gadolinium administration. MR: magnetic resonance.
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F4
Brain MR imaging indicated shrinkage of the cyst on postoperative day 25 (Fig. 4F-4J).