Encapsulated acute subdural hematoma mimicking acute epidural hematoma on computed tomography

The interdural hematoma: A subtype of convexity subdural/dural hematoma with specific radioanatomical characteristics

Background

Rare cases of biconvex hematomas splitting the convexity dura mater were reported and denominated interdural hematoma (IDH). Due to their rarity, little is known about their radiological characteristics, and in most cases, their invasive management with craniotomy and dural membrane excision is unnecessary.

Case Description

We report here a case of single burr-hole endoscopic evacuation of an IDH and its complete resolution after the 6-month follow-up imaging. The literature review reveals 11 reported cases of IDH. Most of them are male and the mean age is 65 years (range 51-90). Most of the reported IDHs were misdiagnosed as epidural hematoma or meningioma, and therefore, they have been managed invasively through craniotomy with dural excision. Diagnosis of the interdural nature was confirmed macroscopically during surgery in all cases and histology was reported for 6 cases. Image analysis found a double dural beak sign and biconvex shape on coronal planes, subarachnoid space enlargement at the collection extremities, and irregular thick inner wall as common radiological aspects of the IDH.

Conclusion

IDH is a rarely reported and often misdiagnosed dural hematoma subtype. Its invasive treatment through craniotomy is likely related to its unknown radiological characteristics. We review and raise awareness about potentially unique radiological anatomy that could avoid unnecessary invasive treatment. Moreover, we report the first case of endoscopically evacuated IDH with long-term follow-up imaging showing complete resolution.

Spontaneous Development of Encapsulated Subdural Hematoma in the Posterior Cranial Fossa after Cardiac Surgery: A Case Report

We report a case of an encapsulated subdural hematoma in the posterior cranial fossa, showing spontaneous development and rapid increase in size after cardiac surgery. An 86-year-old woman underwent aortic valve replacement for aortic valve stenosis, followed by anticoagulant therapy with heparin. Three days after the cardiac surgery, she complained of headache. Computed tomography revealed development of a subdural hematoma in the posterior cranial fossa. The hematoma rapidly increased in size within 7 days. Eleven days after cardiac surgery, she underwent removal of the subdural hematoma by craniotomy. Intraoperatively, the subdural hematoma was covered by a thick granulomatous capsule, with histopathological findings similar to those of a chronic subdural hematoma. She was discharged 2 weeks after the craniotomy without any neurological deficits. Encapsulated subdural hematoma in the posterior cranial fossa is rare and its etiology is unknown. In this case, postoperative anticoagulant therapy can promote the rapid growth of thick hematoma capsule. It is possible that previously reported cases of "posterior fossa chronic subdural hematoma" contain similar lesions to that in our patient.

Chronic encapsulated intraventricular hematoma in a pediatric patient: case report

Chronic encapsulated intraventricular hematoma (CEIVH) is a rare, intraventricular, nonneoplastic mass lesion that can become symptomatic from mass effect or obstructive hydrocephalus. Only 5 cases have been reported in the literature, and only one of these occurred in a pediatric patient and dates back to the pre-modern neuroimaging and pre-microsurgical era of neurosurgery. Imaging features can mimic those of many more common intraventricular lesions, such as choroid plexus tumors or cavernous malformations. In all reported symptomatic cases, resection was safely performed and led to a cure and symptom resolution. Here, the authors present a case of CEIVH in a pediatric patient, describe the operative techniques of resection, review the available literature, and discuss current understanding of the pathophysiology, making this the most comprehensive report on this disease entity to date. The case is a 14-year-old boy who presented with headaches and emesis. Computed tomography showed a hyperdense mass in the trigone of the right lateral ventricle. Magnetic resonance imaging showed a contrast-enhancing well-circumscribed mass. Right temporal craniotomy utilizing a posterior middle temporal gyrus transcortical approach was performed, and gross-total resection was achieved. Pathology revealed a CEIVH. The boy's postoperative course was uncomplicated, and he was discharged 2 days after surgery.

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

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.