Brainstem cavernous malformations: a review with two case reports

Radiation-Induced Cerebral Cavernous Malformations: A Single-Center Experience and Systematic Literature Review

OBJECTIVE

Radiation was first demonstrated to be associated with cavernomagenesis in 1992. Since then, a growing body of literature has shown the unique course and presentation of radiation-induced cavernous malformations (RICMs). This study summarizes the literature on RICMs and presents a single-center experience.

METHODS

A prospectively maintained single institution vascular malformation database was searched for all cases of intracranial cavernous malformation (January 1, 1997-December 31, 2021). For patients with a diagnosis of RICM, information on demographic characteristics, surgical treatments, radiation, and surgical outcomes was obtained and analyzed. A comprehensive literature search was conducted using PubMed, Embase, Cochrane, and Web of Science databases for all reported cases of RICM.

RESULTS

A retrospective review of 1662 patients treated at a single institution yielded 10 patients with prior radiation treatment in the neck or head region and a subsequent diagnosis of intracranial RICM. The median (interquartile range) latency between radiation and presentation was 144 (108-192) months. Nine of 10 patients underwent surgery; symptoms improved for 5 patients, worsened for 3, and were stable for 1. The systematic literature review yielded 64 publications describing 248 patients with RICMs. Of the 248 literature review cases, 71 (28.6%) involved surgical resection. Of 39 patients with reported surgical outcomes, 32 (82%) experienced improvement.

CONCLUSIONS

RICMs have a unique course and epidemiology. RICMs should be considered when patients with a history of radiation present with neurologic impairment. When RICMs are identified, symptomatic patients can be treated effectively with surgical excision and close follow-up.

PIK3CA and CCM mutations fuel cavernomas through a cancer-like mechanism

Vascular malformations are thought to be monogenic disorders that result in dysregulated growth of blood vessels. In the brain, cerebral cavernous malformations (CCMs) arise owing to inactivation of the endothelial CCM protein complex, which is required to dampen the activity of the kinase MEKK31-4. Environmental factors can explain differences in the natural history of CCMs between individuals5, but why single CCMs often exhibit sudden, rapid growth, culminating in strokes or seizures, is unknown. Here we show that growth of CCMs requires increased signalling through the phosphatidylinositol-3-kinase (PI3K)-mTOR pathway as well as loss of function of the CCM complex. We identify somatic gain-of-function mutations in PIK3CA and loss-of-function mutations in the CCM complex in the same cells in a majority of human CCMs. Using mouse models, we show that growth of CCMs requires both PI3K gain of function and CCM loss of function in endothelial cells, and that both CCM loss of function and increased expression of the transcription factor KLF4 (a downstream effector of MEKK3) augment mTOR signalling in endothelial cells. Consistent with these findings, the mTORC1 inhibitor rapamycin effectively blocks the formation of CCMs in mouse models. We establish a three-hit mechanism analogous to cancer, in which aggressive vascular malformations arise through the loss of vascular 'suppressor genes' that constrain vessel growth and gain of a vascular 'oncogene' that stimulates excess vessel growth. These findings suggest that aggressive CCMs could be treated using clinically approved mTORC1 inhibitors.

Ruptured pontine cavernomas in infants: a report of two cases

BACKGROUND

Cavernous malformations (CMs) are either congenital or acquired vascular lesions comprised of sinusoid spaces filled with either blood or its breakdown products. They possess a relatively reduced risk of hemorrhage, yet placement within the posterior fossa and especially the brainstem heightens their likelihood to rupture, making them a likely cause of permanent and debilitating neurological deficit, as well as a veritable surgical challenge. Although the incidence of rupture varies with age among reported case series, it is undoubtable that the severity of this occurrence is the highest while the brain is as its most vulnerable period, i.e. during infancy.

CASE PRESENTATIONS

We present two patients, both female, 6.5- and 5-months-old respectively, who presented with brainstem hemorrhage from CM. They suffered from a sudden onset of hemiparesis and were subjected to surgical removal of their lesions and resulting hematomas. Both patients were discharged in a favorable neurological status and are currently alive and in good health.

CONCLUSION

Microsurgical treatment of brainstem CMs in infants is not only possible with minimal deficit, but also advisable if the lesions are symptomatic. Nevertheless, this requires substantial patience and experience to prevent significant loss of blood and injury to the structures of the posterior fossa. We argue that the safest method to prevent further damage from brainstem CM rebleed is to remove these lesions shortly after the initial hemorrhage.

Influence of Pregnancy on Hemorrhage Risk in Women With Cerebral and Spinal Cavernous Malformations

BACKGROUND AND PURPOSE

Pregnancy as a hemorrhage risk factor in women with cavernous malformations (CMs) is controversial. We describe prospective hemorrhage risk in women who become pregnant after an established CM diagnosis.

METHODS

Beginning in 2015, we recruited consecutive patients with radiologically confirmed CM of the brain or spinal cord to participate in a prospective registry. Participants underwent a baseline and annual medical record review, imaging review, and annual surveys to ascertain pregnancies, deliveries, and neurological complications. We collected prospective hemorrhage data on reproductive age women. We calculated prospective hemorrhage rates on childbearing age patients based on the number of hemorrhages occurring post-CM diagnosis during pregnancy and nonpregnancy, divided by the years of follow-up and censored at last follow-up, age 46, or surgery in sporadic-form CM. The hemorrhage rates were compared and the 95% CI presented with a P value of <0.05.

RESULTS

Of 160 women, 90 presented with CM under the age of 46 (average age 31.6 years; 25.6% familial form; 46.7% with hemorrhage; 24.4% brain stem location). These 90 patients had 136 pregnancies before CM diagnosis; 36 pregnancies occurred at or after the diagnosis of CM. Four patients had a hemorrhage while pregnant or postpartum leading to the first CM diagnosis. During 402.6 years of follow-up while not pregnant, 42 hemorrhages occurred prospectively yielding a 10.4% per year (95% CI, 7.5-14.0) risk of hemorrhage while not pregnant. No hemorrhages occurred during 32 prospective pregnancies (26 live births including 1 twinset and 7 nonviable fetuses) after CM diagnosis during 26.9 years of pregnancy time yielding a rate of 0% per year (95% CI, 0-13.6). We found no statistical difference in the rates of hemorrhage during pregnant and nonpregnant time (P=0.09). No hemorrhage occurred during delivery.

CONCLUSIONS

Our prospective data suggest that pregnancy does not increase the risk of hemorrhage in women with a known brain or spinal cord CM and that vaginal delivery is safe in appropriate candidates.

Cerebral cavernous malformation: Management and outcome during pregnancy and puerperium. A systematic review of literature

INTRODUCTION

Cerebral cavernomas malformations (CCMs) are vascular malformations that occur with an incidence of 0,4-0,8 % in general population. The most feared complication is cerebral hemorrhage. Currently there are no guidelines for pregnant women with CCMs. Some authors claimed that many physiological changes related to pregnancy could be linked to an high risk of rupture and bleeding of the cerebral cavernoma. However, more recent studies highlight that the presence of cerebral cavernomatosis is not a contraindication for pregnancy and that the risk of bleeding is similar in pregnant and in non-pregnant women.

AIM OF THE STUDY

The purpose of our work is to analyze, through the study of controversial findings in literature, all the information currently available trying to establish a common approach for management of women with cerebral cavernomatosis in pregnancy, during childbirth and in the puerperium.

FINDINGS

In accordance with existing literature, pregnancy does not appear to be a significant risk factor for the worsening of clinical manifestations associated with the presence of CCMs. Vaginal delivery is not contraindicated in patients with CCMs and there is no indication to perform cesarean section to reduce the incidence of hemorrhage. The only indication for neurosurgery of CCMs in pregnancy is the presence of rapidly progressive symptoms and should be postponed to the puerperium if arises after 30 weeks. The puerperium is a critical time for the woman with cavernomas for the possibility of bleeding and clinical observation must be continued.

CONCLUSION

The patients with a diagnosis of a CCMs can have a pregnancy without any particular risk to themselves and the fetus but should be addressed to highly specialized obstetrics center to assesses the initial individual risk related to their pathology and to follow the pregnancy.