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.

The Relationship Between Hematoma and Pachymeninges in an Interdural Hematoma: Diagnosis and Surgical Strategy

BACKGROUND

The exact location of a hematoma in relation to the pachymeninges contributes to typical radiographic presentations. However, because of the complexity of hematoma evolution and neomembrane formation, an unexpected intraoperative finding can lead to a change of surgical strategy. In addition, the concentration of hemoglobin and its degradation products, the integrity of red blood cells, and the infiltration of fibroblasts, polymorphonuclear neutrophils, and macrophages are factors that affect the imaging characteristics on computed tomography and magnetic resonance imaging as the hematoma ages.

CASE DESCRIPTION

An interdural hematoma (IDH)-a hemorrhage that splits the periosteal dura mater from the meningeal dura mater-is an extremely rare occurrence, and the diagnosis requires confirmation by surgical or pathologic findings. By presenting a case of an IDH that was misdiagnosed as a chronic subdural hematoma before surgery, and reviewing the literature, we propose the radiologic characteristics of presenting both dural border sign and dural beak sign on magnetic resonance imaging as a specific indicator for IDH preoperatively.

CONCLUSIONS

A careful evaluation of cerebral expansion before membranectomy was mandatory intraoperatively. For IDH, wide inner membranectomy (i.e., excision of meningeal dura mater) should not be necessary. An IDH should be considered as a distinct disease category when evaluating an extra-axial hematoma despite its rarity, because the characters of radiologic, histopathologic findings are different. In addition, surgical strategy varies for epidural or subdural hematoma in different hematoma stages.

A blackhole over brain: Interdural hematoma - A challenging diagnosis

Hematoma in between two dura leaves, named as 'interdural hematoma', is a very rare entity in adulthood. Interdural hematoma may emerge spontaneously or secondary to coagulopathies. A 61-year-old male patient, who had a medical history of alcoholic cirrhosis, presented with interdural hematoma. The case has been discussed with a literature review about diagnostic and therapeutic approaches in this pathology.