Radiological classification of meningiomas with hemorrhagic onset and its clinical significance.

Meningiomas are the most common benign intracranial tumors and frequently present with a gradual onset of neurological deficits; conversely, their acute presentation with hemorrhagic onset appears to be a rare event. Nonetheless, as early surgical evacuation is the foundation of treatment, a timely diagnosis of this rare type of intracranial hemorrhage is necessary. The purpose of the present single-center study was to investigate the radiological characteristics and propose a new bleeding classification for guiding the diagnosis and treatment. A total of 19 patients consecutively diagnosed with hemorrhagic meningioma were enrolled in this retrospective study. Intracranial extra-axial mass, tumor-associated hemorrhage and peritumoral brain edema were the three main radiological features of the hemorrhagic meningiomas. The site of tumor-associated hemorrhage included the peritumoral space, subarachnoid space, subdural space, brain parenchyma and/or intratumor region. Based on the anatomical relationship between meningioma and hematoma, the spontaneous hemorrhage stemming from meningiomas was further summarized into three bleeding patterns involving purely intratumoral hemorrhage (type I), purely extratumoral hemorrhage (type II) and combined intra/extratumoral hemorrhage (type III); furthermore, the type III hemorrhage usually came from type I bleeding that extended into the surrounding regions. The symptoms in type I patients were generally mild and early surgery was performed following adequate preoperative evaluations. The symptoms in type II patients were mild in certain cases and moderate to severe in others, so early or emergency surgery was chosen according to the clinical status of the patient. Almost all type III patients had moderate to severe symptoms and these patients usually required emergency surgery. In addition, patients with different bleeding types may have different pathological mechanisms underlying the tumor bleeding. Apart from being convenient for diagnosis, this concise and practical bleeding classification may aid in the selection of the treatment strategy and facilitate the understanding of the associated mechanisms.