Korean J Neurotrauma.  2014 Oct;10(2):142-145. 10.13004/kjnt.2014.10.2.142.

Encapsulated Unresolved Subdural Hematoma Mimicking Acute Epidural Hematoma: A Case Report

• Park SS
• Shin WR
• Kim HJ
• Kwon CY

• KMID: 2256254
• DOI: http://doi.org/10.13004/kjnt.2014.10.2.142

Abstract

Encapsulated acute subdural hematoma (ASDH) has been uncommonly reported. To our knowledge, a few cases of lentiform ASDH have been reported. The mechanism of encapsulated ASDH has been studied but not completely clarified. Encapsulated lentiform ASDH on a computed tomography (CT) scan mimics acute epidural hematoma (AEDH). Misinterpretation of biconvex-shaped ASDH on CT scan as AEDH often occurs and is usually identified by neurosurgical intervention. We report a case of an 85-year-old man presenting with a 2-day history of mental deterioration and right-sided weakness. CT scan revealed a biconvex-shaped hyperdense mass mixed with various densities of blood along the left temporoparietal cerebral convexity, which was misinterpreted as AEDH preoperatively. Emergency craniectomy was performed, but no AEDH was found beneath the skull. In the subdural space, encapsulated ASDH was located. En block resection of encapsulated ASDH was done. Emergency craniectomy confirmed that the preoperatively diagnosed AEDH was an encapsulated ASDH postoperatively. Radiologic studies of AEDH-like SDH allow us to establish an easy differential diagnosis between AEDH and ASDH by distinct features. More histological studies will provide us information on the mechanism underlying encapsulated ASDH.

Keyword

Hematoma epidural cranial; Hematoma subdural acute; Hematoma; Cerebral hemorrhage

MeSH Terms

Aged, 80 and over
Cerebral Hemorrhage
Diagnosis, Differential
Emergencies
Hematoma*
Hematoma, Subdural*
Hematoma, Subdural, Acute
Humans
Skull
Subdural Space
Tomography, X-Ray Computed

Figure

• 

  FIGURE 1 A: Incompletely resolved chronic subdural hematoma after burr hole trephination 4 years prior to admission. A thick-walled isodense lesion is seen in the left temporoparietal cerebral convexity. B: Preoperative computed tomography scan shows a lentiform lesion (8×3.8 cm) with high density partially mixed with isodensity to low density, in the left temporoparietal cerebral convexity. Large amounts of subdural fluid collection along both cerebral convexities are seen. C: Postoperative CT scan shows a newly developed hematoma. An acute subdural hematoma along the interhemispheric fissure and left cerebral convexity is seen.

• 

  FIGURE 2 Photograph of the encapsulated hematoma in the subdural space shows the dura mater (thin black arrow), outer/inner neomembrane (thick black arrow), solid fresh blood clots with old mud-like blood clots (white arrow), and an intact brain parenchyma.

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  FIGURE 3 Photograph of resected hematoma. The thick outer neomembrane shows hyaline degeneration, and the thin inner membrane has meningothelial cells and hemosiderin pigments produced by old hemorrhage. A: The dura membrane has plentiful vascular structures (arrow). B: Hemosiderin pigments (arrow). C: Meningothelial cells (arrow). Hematoxylin and eosin staining. Original magnifications are marked by bars.

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