Surgical Clipping of a Petrosal Tentorial Dural Arteriovenous Fistula (Lawton's Type 5).

Objectives To demonstrate the surgical clipping of a lateral petrosal tentorial dural arteriovenous fistula (DAVF), located in the cerebellopontine angle (CPA), through a retrosigmoid approach. Method A previously healthy 49-year-old man presented a sudden episode of headache, photophobia, and dizziness. Due to the persistence of his symptoms despite proper analgesic treatment, he sought medical attention. The initial computed tomography (CT) scan showed a hyperdense lesion in the left CPA. Magnetic resonance imaging (MRI) demonstrated the vascular nature of the lesion, corresponding to an engorged superior petrosal vein (SPV) and Rosenthal's vein. The preoperative angiography showed a lateral tentorial DAVF (Lawton's type 5), fed by multiple transpetrous branches coming off the external carotid artery, and draining into the SPV. A standard retrosigmoid approach was planned for clipping and exclusion of the DAVF. Results Through a left retrosigmoid craniotomy the DAVF was approached, along with the different neurovascular structures of the CPA. The DAVF originated at the tentorial petrosal junction. The fistulous vein was closely attached to the trigeminal nerve and the anterior inferior cerebellar artery (AICA). The fistulous vein was dissected and clipped close to its base at the lateral tentorium, achieving complete occlusion of the DAVF. The patient fully recovered after surgery with neither relapse of his symptoms nor postoperative complications. Conclusion The retrosigmoid craniotomy is the best surgical approach for lateral tentorial DAVFs, as it provides a direct way to the fistula origin and permits a successful clipping of the draining vein. The link to the video can be found at: https://youtu.be/Fj3uqrTPX5c .

Arteriovenous Malformations of the Temporalis Muscle: A Comprehensive Review.

Arteriovenous malformations of the temporalis muscle (TM-AVMs) are rare lesions commonly considered as a variant of scalp AVMs. A study was designed in order to analyze TM-AVMs features and to confirm them as a certain entity different from scalp AVMs. Seven TM-AVMs cases (5 from literature plus 2 from our database) were studied. Clinical, epidemiological, radiological, and therapeutic data were analyzed and compared to common scalp AVMs features. All TM-AVMs presented as large soft tumor-like masses on the temporal region (mean diameter: 6 cm). Pain was referred in half of cases, while overlying cutaneous stigmas were described only once. No masticatory malfunction was reported. TM-AVMs tend to appear in young patients (mean: 29 yr), commonly as longstanding and slow-evolving lesions (mean evolution time before diagnosis: 5 yr). All cases displayed a diffuse slow-flow blush on angiogram. All TM-AVMs were completely located within the TM, with no involvement of scalp or bone. The pathological analysis of all cases demonstrated the presence of striate muscular bundles intermingled with fairly mature arterial and venous vessels. No clearly distorted vessel was found within the TM-AVMs. Surgery was performed for all cases with complete removal. Preoperative embolization was done in 4 cases to reduce blood loss during surgery. No clinical/radiological recurrence was reported. Opposite to TM-AVMs, scalp AVMs commonly present as high-flow lesions with no evident tumor mass, mainly located in the subcutaneous tissue. TM-AVMs present clearly distinct features compared to scalp AVMs, for which they should be considered as a certain pathological entity and not as a variant of scalp AVMs.

Chiari type 1 anomaly in pseudohypoparathyroidism type Ia: pathogenetic hypothesis.

AIM: This study aims to report a patient with Chiari type 1 malformation (CM1) occurring in the context of pseudohypoparathyroidism type 1a (PHP-Ia) that we believe represents the first instance of this association in the current literature. CASE REPORT: The authors describe the case of a 6-year-old girl diagnosed with PHP-Ia who presented an associated tonsillar descent. During the follow-up, the skull vault and the occipital squama became extremely thickened at the same time as the tonsillar herniation showed a marked regression. DISCUSSION: Chronic tonsillar descent has been reported in diverse genetic and metabolic diseases of bone. A constant finding in PH-Ia consists of changes that mainly involve the bones of the patients' hands and feet. Cerebral anomalies have also been documented in PHP-Ia, especially cerebral calcifications, but in contrast involvement of the skull bones has seldom been described in this condition. The authors briefly discuss the probable role played by the observed skull changes in the origin and subsequent regression of the tonsillar descent in this child. CONCLUSIONS: We suggest that CM1 may develop in patients with PHP-Ia and that it should be actively sought, especially in individuals diagnosed with PHP-Ia presenting with neurological manifestations. Probably, the seeming rarity of chronic tonsillar descent in PHP-Ia is due to the fact that many patients with this condition are rarely investigated with magnetic resonance.

Cavernous hemangiomas of the cranial vault in infants: a case-based update.

BACKGROUND: Mass lesions arising in the scalp or the cranial vault of children require a significant diagnostic work-up but their nature, in most instances, can only be clarified after histopathological study. Tumors of osseous consistency or merging from within cranial bones are seldom susceptible of fine needle aspiration biopsy and require excision. Ossified cephalhematoma is a rare entity that is usually related to perinatal or accidental trauma. Exceptionally, ossified cephalhematoma has a non-traumatic origin and arises from a different condition, as vascular tumor or malformation. DISCUSSION: Cavernomas of the skull are infrequent and occur in middle-aged individuals. Skull cavernomas in infants lack the sunburst radiographic pattern seen in adults and may present as a bone-like tumor whose appearance is identical to that of ossified cephalhematoma. A literature search showed only two previous reports of patients younger than 1 year with skull cavernomas presenting with associated ossified cephalhematomas. We hypothesize that this type of skull cavernomas are congenital in origin and that they manifest precociously due to the occurrence of early bleeding. CASE ILLUSTRATION: We report a 12-month-old boy presenting with a hard tumor arising on his right parietal bone that was present since birth. After diagnostic work-up, the bone tumor and the associated intraosseous hematoma were removed. Interestingly, the source of the hematoma was a cavernous hemangioma originating in the skull. CONCLUSIONS: Calvarial cavernous hemangiomas may bleed precociously, even before birth, and manifest as large intraosseous hematomas. Differential diagnosis against ossified cephalhematoma can only be established through histopathological study.