We experienced a JFS case which was accompanied with acute tumor expansion after SRS and subsequent clinically significant intratumoral hemorrhage. Intratumoral hemorrhage of intracranial schwannoma, mostly vestibular schwannoma, has been recently considered as more common than previously believed owing to advances in imaging studies and larger analyses. The etiology of intratumoral hemorrhage in intracranial schwannoma has not completely defined and is likely to be multifactorial. Anticoagulation therapy, high tumor vascularization, hypertension and large tumor have been recognized as a risk factor.19–24 Especially, rapid tumor growth causes relative shortage of blood supply and tumor necrosis, resulting in increased intratumoral pressure and hemorrhage. These repeated microhemorrhage also lead to cystic changes and further expansion.23, 25–27 Although microhemorrhage alone is asymptomatic in most cases, some patients infrequently present with the abrupt symptom progression.27 Regarding vestibular schwannoma, about 50 cases have been reported in literature.27, 28 Carlson et al. estimated that the rate of intratumoral hemorrhage in untreated vestibular schwannoma was 0.4%, which decreased to only 0.2% after excluding patients on anticoagulation.19 The symptoms are headache, nausea and vomiting, cranial neuropathy, ataxia and so on. Special care is needed for them because these symptoms can occasionally be life-threatening due to vicinity of brainstem.
Influence of radiation on the intratumoral hemorrhage of intracranial schwannoma has not been fully elucidated. In particular, limited to clinical significant hemorrhage, there are eight reported case in literature (Table 1).22, 28–33
Table 1
Literature review about cases with symptomatic intratumoral hemorrhage after SRS for intracranial schwannoma.
Author, year | Age, sex | Disease | Modality | Dose | Interval from SRS to hemorrhage | Main symptom | Treatment |
Iwai et al., 200329 | 70. F | VS | GK | 12 Gy (NR) | 60 months | ataxia | resection |
NR | VS | GK | NR | 80 months | pain | conservative |
Karampelas, 200731 | 53, M | VS | GK | 13 Gy (46%) | 27 months | headache, facial spasm | conservative |
Dehdashti, 200922 | 47, F | VS | GK | NR | 18 months | headache, ataxia | resection |
Mandl, 200933 | 59, F | VS | NR | 25 Gy/5Fr (80%) | 75 months | headache, ataxia, papilledema | resection |
Miki, 201530 | 48, M | VS | GK | 12 Gy (50%) | 46 months | facial palsy | resection |
Thombre, 201928 | 63, M | VS | GK | 12 Gy (50%) | 10 days | vertigo, facial palsy | resection |
Noureldine, 202032 | 71, F | FS | CK | 21 Gy/3Fr* | 3 days | headache, facial palsy | resection |
Present case | 64, M | JFS | GK | 13 Gy (50%) | 7 months | headache | conservative |
CK = CyberKnife, FS = facial schwannoma, GK = Gamma Knife, JFS = jugular foramen schwannoma, NR = not reported, SRS = stereotactic radiosurgery, VS = vestibular schwannoma |
* Hemorrhage occurred 3 days after the first fraction, and 7 Gy had been irradiated to tumor. |
Some mechanism could be assumed from previous studies. First, radiation induces microhemorrhage as well as other estimated factors, leading to necrotic expansion and rarely massive hemorrhage.34 Second, radiation would also trigger thrombosis of irradiated endothelial cells, with increase in intravascular outflow resistance and progress in venous congestion, contributing spontaneous intratumoral hemorrhage.35 It is noteworthy that our case provided sequential MRIs before hemorrhage, which showed relatively rapid tumor expansion with peritumoral edema, finally resulted in symptomatic hemorrhage. Considering venous compromise which had already existed prior to SRS, it is possible that exacerbated venous congestion promoted subsequent hemorrhage in this case.
The optimal treatment for the intratumoral hemorrhage with brainstem compression is basically resection. The previously reported post-SRS cases were managed surgically in six cases and conservatively in two other cases, largely ending up in a good recovery (Table 1). 22, 28–33 Although our patient experienced headache, nausea and mild cranial neuropathy due to intratumoral hemorrhage, he quickly improved and the tumor demonstrated remarkable shrinkage without further intervention, suggesting that necrotic changes mainly caused intratumoral hemorrhage and did not necessarily mean failed tumor control. Based on our experience, conservative treatment with osmotic diuretics and corticosteroids would be also reasonable unless progressive neurological deterioration is evident. Nevertheless, this is just a case report; thus, accumulation of additional cases and further research is needed to validate these findings. This is the first case reported to demonstrate intratumoral hemorrhage after SRS for JFS. With conservative treatment, subsequent tumor shrinkage was observed in this case. While the etiology is not completely understood, radiation-induced tumor expansion and possible venous compromise are likely to cause the intratumoral hemorrhage. Although surgical resection is needed to be considered at first, conservative management could control the condition unless the hemorrhage is devastating or results in remarkable brainstem compression. Intratumoral hemorrhage should therefore be recognized as one of potential sequelae after SRS for JFSs.