====== Intratumoral hemorrhage ======

====Etiology====
Intratumoral [[hemorrhage]] is thought to originate from abnormal newborn [[vessel]]s that traverse [[necrosis]] areas
((Wakai S, Yamakawa K, Manaka S, Takakura K. Spontaneous intracranial hemorrhage caused by brain tumor : its incidence and clinical significance. Neurosurgery. 1982;10:437–444.)) 
or from tumoral invasion of large vessels
((Zimmerman RA, Bilaniuk LT. Computed tomography of acute intratumoral hemorrhage. Radiology. 1980;135:355–359.))
, leading to thinning and rupture of the vessels walls. Another potential mechanism would be relatively weak tumor vessels, which are not well invested with a glial meshwork; this may contribute to reduced resistance to the shearing forces of the brain
((Can SM, Aydin Y, Turkmenoglu O, Aydin F, Ziyal I. Giant cell glioblastoma manifesting as traumatic intracerebral hemorrhage--case report. Neurol Med Chir (Tokyo) 2002;42:568–571.)).
Endothelial proliferation with subsequent obliteration of the lumen or presence of intratumoral arteriovenous fistulae are alternate explanations for intratumoral bleeding
((Schrader B, Barth H, Lang EW, Buhl R, Hugo HH, Biederer J, et al. Spontaneous intracranial haematomas caused by neoplasms. Acta Neurochir (Wien) 2000;142:979–985.)).
Thus, hemostasis often cannot be easily achieved at hematoma removal; this finding indicates the possibility of brain tumors as a cause of bleeding
((Watanabe K, Wakai S, Okuhata S. Gliomas presenting with basal ganglionic haemorrhage. Report of two cases. Acta Neurochir (Wien) 1997;139:787–788. )).

====Epidemiology====
There have been known risk factors of intratumoral hemorrhage. Hemorrhage more often develops in malignant tumors such as [[glioblastoma multiforme]] and [[brain metastasis]]
((Kondziolka D, Bernstein M, Resch L, Tator CH, Fleming JF, Vanderlinden RG, et al. Significance of hemorrhage into brain tumors : clinicopathological study. J Neurosurg. 1987;67:852–857.))
((Wakai S, Yamakawa K, Manaka S, Takakura K. Spontaneous intracranial hemorrhage caused by brain tumor : its incidence and clinical significance. Neurosurgery. 1982;10:437–444.))
((Yuguang L, Meng L, Shugan Z, Yuquan J, Gang L, Xingang L, et al. Intracranial tumoural haemorrhage--a report of 58 cases. J Clin Neurosci. 2002;9:637–639.)).
The incidence of tumor bleeding in malignant astrocytoma in one study was 6%
((Kondziolka D, Bernstein M, Resch L, Tator CH, Fleming JF, Vanderlinden RG, et al. Significance of hemorrhage into brain tumors : clinicopathological study. J Neurosurg. 1987;67:852–857.))
while that in glioblastoma and metastatic brain tumors were 6.5-8% and 7-9%, respectively). Among benign neuroepithelial tumors, the incidence of hemorrhage from mixed glioma and oligodendroglioma was much higher than the other tumors
((Kondziolka D, Bernstein M, Resch L, Tator CH, Fleming JF, Vanderlinden RG, et al. Significance of hemorrhage into brain tumors : clinicopathological study. J Neurosurg. 1987;67:852–857.)) 
((Wakai S, Yamakawa K, Manaka S, Takakura K. Spontaneous intracranial hemorrhage caused by brain tumor : its incidence and clinical significance. Neurosurgery. 1982;10:437–444.)).
On the other hand, pituitary neuroendocrine tumor and meningiomas have the high risk for developing intratumoral hemorrhage among benign non-neuroepithelial tumors
((Yuguang L, Meng L, Shugan Z, Yuquan J, Gang L, Xingang L, et al. Intracranial tumoural haemorrhage--a report of 58 cases. J Clin Neurosci. 2002;9:637–639.)).
The location of bleeding depends on the different site of brain tumor even though intratumoral hemorrhage usually develops in the atypical location of hypertensive intracerebral hemorrhage and the patients often have no history of hypertension
((Yuguang L, Meng L, Shugan Z, Yuquan J, Gang L, Xingang L, et al. Intracranial tumoural haemorrhage--a report of 58 cases. J Clin Neurosci. 2002;9:637–639.))
((Zimmerman RA, Bilaniuk LT. Computed tomography of acute intratumoral hemorrhage. Radiology. 1980;135:355–359.)).


Intratumoral hemorrhage occurs most frequently in [[pituitary neuroendocrine tumor]] among all types of brain tumors
((Wakai S, Yamakawa K, Manaka S, et al. Spontaneous intracranial hemorrhage caused by brain tumor: its incidence and clinical significance. Neurosurgery 1982;10:437–44 )).

====Diagnosis====
Radiological studies with contrast material usually distinguish tumors from hemorrhage, as the border between the tumors and hemorrhage is usually clear
((Nakayama Y, Tanaka A, Yoshinaga S, Ueno Y. [Indications for surgery to determine the etiology of subcortical hemorrhage] No Shinkei Geka. 1998;26:1067–1074.)).
In contrast, if the tumors are compressed by a large hemorrhage, or the border between the tumors and hemorrhage is unclear, intratumoral hemorrhage may be indistinguishable from spontaneous ICH, even though contrast material is used
((Inamasu J, Kuramae T, Nakatsukasa M. Glioblastoma masquerading as a hypertensive putaminal hemorrhage : a diagnostic pitfall. Neurol Med Chir (Tokyo) 2009;49:427–429.)).
Thus, a CT with contrast cannot exclude underlying pathologies that may cause ICH, especially if the patient has a history of hypertension, and the location is typical for hypertensive ICH. MRI with gadolinium in the early follow-up period would likely have lead to earlier detection of the tumors in the present case. However, Inamasu et al.
((Inamasu J, Kuramae T, Nakatsukasa M. Glioblastoma masquerading as a hypertensive putaminal hemorrhage : a diagnostic pitfall. Neurol Med Chir (Tokyo) 2009;49:427–429.))
suggested that in terms of cost effectiveness, it is controversial to have every patient presenting with typical hypertensive ICH undergo MRI with gadolinium to rule out intratumoral bleeding.

===== Case reports =====

A 63-year-old gentleman who had right-side severe [[sensorineural hearing loss]] on MRI showing a right [[cerebellopontine angle tumor]] (volume 4.96 cm3) with an [[internal acoustic meatus]] extension. He underwent [[GKRS]] with the prescription dose of 12 Gy to the 50% isodose line, covering 4.66 cm3 (i.e., 94%) of the tumor. Ten days later, he experienced a symptomatic intra-lesional hemorrhage with a mass effect over the [[brainstem]]. When symptoms did not resolve after an initial conservative approach, he underwent surgical decompression of the lesion. Postoperatively, the patient had [[facial palsy]] but was free of disabling [[vertigo]] and [[ataxia]]. At the 6-month follow-up, he was doing well without any other complaints. Although rare, an intralesional bleed can occur after GKRS in [[Vestibular Schwannoma]] and should be suspected when new severe symptoms develop immediately after therapy
((Thombre B, Sadashiva N, Krishnan JB, Prabhuraj AR, Rao KN, Arima A.
Symptomatic Post-Radiosurgery Intratumoral Hemorrhage in a Case of Vestibular
Schwannoma: A Case Report and Review of the Literature. Stereotact Funct
Neurosurg. 2019 Nov 26:1-5. doi: 10.1159/000504264. [Epub ahead of print] PubMed 
PMID: 31770766.
)).