UNASSIGNED: 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.
UNASSIGNED: 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.
UNASSIGNED: 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.

Spontaneous thrombosis of an unruptured large or giant saccular intracranial aneurysm is a well-known phenomenon and can cause ischemic stroke (IS), which is a rare event. The possible pathogenic mechanisms of IS include distal embolic occlusion secondary to migration of the intra-aneurysmal thrombus, occlusion of the parent artery lumen caused by the retrograde extension of the aneurysmal thrombosis, external compression of the parent artery due to the increased aneurysmal mass effect. Among these, IS due to simultaneous thromboses of the aneurysm and its parent artery is extremely rare, with only a few cases reported in the literature. Herein, we present a case of a 18-year-old woman who suffered an acute IS, attribute to spontaneous complete thrombosis of an unruptured large saccular aneurysm of the right middle cerebral artery with occlusion of the parent artery, and we review the literature simultaneously.

UNASSIGNED: Giant cavernous carotid artery aneurysms (>25 mm) are rare (3-5%), with some prone to spontaneous thrombosis (10-20% complete). We present a unique case of one of the largest aneurysms spontaneously thrombosing and calcifying.
UNASSIGNED: A 57-year-old with persistent right-sided headaches had a substantial hyperdense mass in the right middle cranial fossa, eroding petrous bone. Magnetic resonance imaging and digital subtraction angiography revealed a giant cavernous segment fusiform aneurysm of the right internal carotid artery (ICA) with spontaneous thrombosis and distal ICA occlusion. Collateral circulation maintains the cerebral blood supply. Despite anatomical challenges, conservative management was chosen due to the patient\'s stability.
UNASSIGNED: This case highlights the complex interplay between thrombosed giant aneurysms and affected vessels, with unique features such as cross-flow, calcification, and bone erosion. We advocate conservative management for stable cases, supported by literature, emphasizing vigilant follow-up. This expands the spectrum of aneurysm presentations and encourages further research into their dynamics.

The most common manifestation of brain arteriovenous malformations (BAVM) is intracranial hemorrhage. The incidence of ruptured BAVM is 3.5 per 100,000 people per year. The mortality rate of ruptured BAVM within 1 month after diagnosis was 12.7%. Spontaneous thrombosis occurs in less than 1.5% of ruptured BAVMs. This phenomenon was still elusive. Up until now, the gold standard of imaging examination has been cerebral digital subtraction angiography (DSA), whose sensitivity and specificity reach 100%. We reported the spontaneous thrombosis of a ruptured deep BAVM. An 18-year-old woman presented with severe headache and vomiting. The patient also complained of seizures. There was no body weakness, skewed face, or slurred speech. Cerebral computed tomography (CT) showed extensive hemorrhage in the ventricular system and subarachnoid space. Cerebral DSA showed a left subcortical BAVM and was found to have spontaneous thrombosis 3 weeks later when the patient was about to be embolized. Spontaneous thrombosis of ruptured BAVM may occur after intracranial hemorrhage. In this patient, spontaneous thrombosis occurred within 3 weeks.

Hepatic pseudoaneurysm (HPA) is a rare complication of liver injury in children. Prophylactic embolization is preferable to prevent life-threatening hemorrhage due to pseudoaneurysm rupture. We present the case of a four-year-old boy who sustained a grade III liver injury from blunt abdominal trauma. He was conservatively managed since he was hemodynamically stable. Follow-up contrast-enhanced computed tomography (CECT) performed 10 days following the injury revealed an HPA measuring 4 mm × 4 mm × 3 mm. Herein, we chose conservative treatment for HPA as the patient was asymptomatic and hemodynamically stable. Conservative treatment was successful, and HPA spontaneously resolved 23 days following the injury without radiologic or surgical intervention. Although there are studies reporting asymptomatic HPAs that have spontaneously resolved, the natural history of HPAs remains unknown. Conservative treatment may be an option for asymptomatic HPA; however, to identify factors contributing to spontaneous thrombosis, further evaluation is needed.

Unruptured giant intracranial aneurysms (GIAs) are characterized by their size, which exceeds 25 mm, and these conditions account for approximately 5% of all aneurysm cases. Furthermore, it typically develops in women during the fifth to seventh decade of life. Compared to small aneurysms, which cause subarachnoid hemorrhage, GIAs can manifest as masses or ischemic effects caused by thromboembolism. An elderly female patient, aged 67, was admitted to the hospital with a primary complaint of sudden facial sensory loss on the left side and vomiting. There was also a history of double vision accompanied by left ocular movement disturbance and gradually developed localized headache on the left side. Furthermore, a contrast head magnetic resonance angiography (MRA) revealed the presence of a high-flow giant aneurysm, measuring 30.7 × 31.8 × 27.2 mm in the cavernous segment of the left internal carotid artery (ICA). Cerebral angiography showed the absence of flow on the left ICA due to total occlusion. After cerebral angiography, the patient remained conscious but exhibited some neurological deficits, which were identical to the initial symptoms observed during hospitalization. Cases of spontaneous thrombosis in GIA are extremely rare. However, radiological examination, particularly angiography, can be used to diagnose spontaneous thrombosis in unruptured GIAs to ensure that the patient receives the right treatment.

Cerebral aneurysm is a known cause of spontaneous subarachnoid hemorrhage (SAH). Furthermore, this condition is often asymptomatic, but the occurrence of a rupture can lead to fatal complications. The incidence of spontaneous thrombosis in saccular aneurysm is rare, with an incidence rate of 1%-2%. The most common sites include the middle cerebral artery (MCA) (41%), posterior communicating artery (PCOMM) (15%), and posterior inferior cerebellar artery (PICA) (11%). A head computed tomography angiography (CTA) with contrast is a common diagnostic tool for detecting SAH in the temporoparietal area, hippocampal gyrus, and right fissure of Sylvie. In some cases, saccular aneurysm can be found in the segment bifurcation of the right middle cerebral artery. A cerebral angiography was carried out, specifically digital subtraction angiography, which revealed the presence of visible blister remnants of aneurysm in the form of spontaneous thrombosis. After 1 year, another angiography evaluation was performed to assess the condition of the patient. Furthermore, the results showed no evidence of recanalization and there were no new neurologic deficits. Although spontaneous thrombosis led to the healing of aneurysm in some cases, secondary recanalization remained a possibility. Therefore, it was essential to monitor any incidence of this complication. Precise knowledge of the mechanism of spontaneous thrombosis could lead to the development of new therapeutic approaches. Spontaneous thrombosis in cases of saccular aneurysm is a rare occurrence, which can provide temporary or permanent benefits to the patient. Therefore, periodic evaluation is required to assess the condition of the patient.

Vein of Galen malformation (VOGM) is an exceptionally uncommon form of congenital intracranial vascular malformations. It is highly unusual for this lesion to spontaneously thrombose. The clinical presentation of a patient may range from being asymptomatic to critically ill. The underlying pathophysiological mechanisms that cause spontaneous thrombosis are still poorly understood.
The literature on spontaneous thrombosis of VOGM was systematically reviewed, analyzed, and summarized with a focus on its pathophysiology, types, clinical presentations, diagnosis, management, and outcomes. It was also illustrated with a case presentation. The case presents an unusual presentation and location of a VOGM in a 2-year-old boy who was successfully treated with surgical resection.
A handful of cases of thrombosed VOGM have been reported worldwide where surgery was used to treat the condition. Low-flow fistulas of the mural type are prone to spontaneous thrombosis, have delayed clinical presentations, and are typically diagnosed in young children. Among the many possible manifestations, hydrocephalus is by far the most common. In the absence of blood flow, MRI is the diagnostic test of choice. Depending on the patient\'s symptoms, surgery to either remove the aneurysm or divert the cerebrospinal fluid usually results in a good prognosis.

Core needle biopsy is currently the most widely used basic diagnostic method for the diagnosis of breast masses; it is a minimally invasive procedure with excellent specificity and sensitivity and negligible complication rates, particularly when image-guided. However, complications tend to be higher when performed blindly. Hematoma remains the most common complication resulting from this procedure. Iatrogenic pseudoaneurysm is a rare complication with no previous report in Nigeria. In this report, we present a case of breast pseudoaneurysm occurring after 2 blind, palpation-guided core needle biopsies in a 51-year-old known hypertensive woman at a Nigerian tertiary hospital. Spontaneous thrombosis of the pseudoaneurysm occurred over three months after the second blind biopsy.

BACKGROUND: The pathogenesis and endovascular treatment strategy for spontaneously thrombosed unruptured cerebral aneurysms have not yet been comprehensively described.
METHODS: The authors reported on a 78-year-old woman who had large bilateral unruptured cavernous carotid artery aneurysms that induced chronic disseminated intravascular coagulation and acquired factor XIII deficiency. The right aneurysm was symptomatic and partially thrombosed. Hemorrhagic diathesis and abnormal values of laboratory data improved after administration of recombinant human thrombomodulin followed by endovascular treatment in which three pipeline embolization devices were deployed for the right aneurysm.
CONCLUSIONS: To the best of the authors\' knowledge, this was the first report of an unruptured cerebral aneurysm leading to coagulation disorders with clinical manifestation that was treated successfully by endovascular intervention after intensive perioperative management.