Long-term Surveillance In An Infant With Spontaneous Obliteration Of Pial Arteriovenous Malformation And Large Intranidal Aneurysm: A Unique Case Observation
Iampreechakul, P., Wangtanaphat, K., Wattanasen, Y., Hangsapruek, S., Lertbutsayanukul, P., & Siriwimonmas, S. (2024). Long-term surveillance in an infant with spontaneous obliteration of pial arteriovenous malformation and large intranidal aneurysm: A unique case observation. Surgical neurology international, 15, 206. https://doi.org/10.25259/SNI_45_2024
View Original Source →Abstract
Spontaneous obliteration of untreated cerebral arteriovenous malformations (AVMs) is rare, occurring in <1% of cases, and is even less common in pediatric populations. The mechanisms driving spontaneous regression of brain AVMs remain poorly understood, and long-term surveillance in pediatric patients is infrequently documented. The authors reported a remarkably rare instance of spontaneous thrombosis in a pial AVM accompanied by a large intranidal aneurysm in a 10-month-old infant, initially presenting with a nocturnal seizure. Diagnostic imaging revealed a ruptured intranidal aneurysm causing acute hemorrhage in the left anterior interhemispheric subdural space, extending into adjacent areas. Further, magnetic resonance imaging (MRI) and magnetic resonance angiography delineated the AVM in the left superior frontal gyrus, associated with a thrombosed aneurysm and surrounding edema. Cerebral angiography confirmed the AVM’s origin from the left anterior cerebral artery, displaying early venous drainage and small, indirect feeders not amenable to endovascular treatment. Over time, serial imaging showed the aneurysm’s transition from partial to complete thrombosis. Subsequent MRIs and angiographic assessments up to age 10 confirmed complete resolution of the AVM and aneurysm, with focal hyperemia persisted until age 16, when recurrent AVM was identified. We document a rare spontaneous regression of a pial AVM with an intranidal aneurysm influenced by specific vascular factors. Despite this, spontaneous thrombosis should not replace vigilant long-term monitoring in pediatric neurovascular care.
Case Details
Disease Location
Brain (vascular)
Personal Characteristics
10-month-old female infant
Clinical Characteristics
Nocturnal seizure observed by her mother. The seizure involved screaming, eyes rolling up, and generalized convulsions lasting for 2 min, with no preceding fever or trauma. Brain CT scan revealed a hyperdense, approximately 15 mm mass with surrounding edema in the left superior frontal gyrus and an adjacent acute thin subdural hematoma (sdh). Despite antiepileptic medication, the infant continued to experience seizures and required intubation and transfer to the intensive care unit. The provisional diagnosis was a ruptured aneurysm causing acute sdh, with a differential diagnosis of a hemorrhagic tumor. MRI obtained a week post symptom onset showed the sdh extending along the posterior interhemispheric fissure, posterior falx, bilateral tentorial cerebelli, and over both hemispheric convexities, more pronounced on the left side. The left anterior interhemispheric sdh adjoined the medial side of the large round mass, indicating a probable source of hemorrhage from a ruptured aneurysm. T1-weighted gadolinium-enhanced MRI delineated the mass as a large, partially thrombosed aneurysm with eccentric signal voids and peripheral enhancement. By age 15 she was diagnosed with depressive mood disorder and commenced treatment with sertraline at a dose of 50 mg/day. At age 16 cranial MRI identified a recurrent pial avm located in the left superior frontal region. The decision was made to proceed with stereotactic radiosurgery for the recurrent avm.
Remission Characteristics
One month after symptom onset, a follow-up MRI indicated complete resolution of the sdh and a laminated appearance in the partially thrombosed aneurysm, with persistent perianeurysmal edema. A follow-up MRI 5 months later showed a significant reduction in the aneurysm size and complete resolution of the edema six years after symptom onset a follow-up MRI and contrasted mra confirmed the complete obliteration.
Treatment & Mechanisms
Proposed Remission Mechanisms
The mass effect caused by parenchymal hemorrhage likely led to the stretching and narrowing of feeding arteries, the occlusion of draining veins, or the obliteration of the nidus, which contributed to the spontaneous obliteration of brain avms
Clinical Treatment
Epileptic medication (not specified) sertraline 50mg/day (at age 15) stereotactic radiosurgery
Non-Clinical Treatment
None reported