RESUMO
Carotid splaying, also known as the Lyre sign, is a widening of the carotid bifurcation due to the displacement of the internal carotid artery and the external carotid artery just distal to the point of divergence. This phenomenon is classically exhibited by highly vascularized carotid body tumors and, in rare cases, by cervical sympathetic chain schwannomas. Demonstration of the Lyre sign by a cervical vagal neurofibroma, however, is a unique occurrence that has not been previously documented in the literature. Neurofibromas are slow growing, poorly vascularized soft tissue masses and are a hallmark of the autosomal dominant genetic disorder, neurofibromatosis type 1 (NF-1). While targeted genetic therapies are evolving, management is currently dependent on a case-by-case resection of tumors with specific indications for chemo and radiation therapy. These resections rely on magnetic resonance imaging (MRI) to visualize tumor location and infiltration, but even in the setting of an established NF-1 diagnosis, additional imaging can be beneficial in ruling out more precarious tumors and optimizing surgical outcomes. In this case, a 25-year-old female with known NF-1 presented with an enlarging cervical mass that demonstrated splaying of the left internal and external carotid arteries on MRI. Due to the typical association of the Lyre sign with carotid body tumors, magnetic resonance angiography (MRA) was crucial in guiding surgical decision making. Carotid body tumors are highly vascularized, may compress carotid branches, and carry a high risk of intraoperative bleeding. They are best visualized with MRA, which assesses carotid splaying and patency, and demonstrates vascular blushing within the tumor. This patient's MRA demonstrated the Lyre sign, patency of all carotid vessels, and a lack of vascularity within the mass, thus lowering suspicion for a carotid body tumor. Intraoperative use of imaging results facilitated a successful resection of a soft tissue tumor with minimal blood loss and no complications. Postoperative histologic examination confirmed a neurofibroma and definitively ruled out a carotid body tumor. This case highlights the importance of utilizing MRA whenever carotid splaying is seen on MRI and supports the consideration of neurofibromas in the differential for this finding.
RESUMO
BACKGROUND: Cavernous hemangiomas account for 5%-13% of central nervous system vascular lesions. They are usually found intra-axially but rarely involve extra-axial structures, most commonly the middle cranial fossa. A cavernous hemangioma manifesting as a clinoid meningioma is extremely rare. CASE DESCRIPTION: A 36-year-old man presented with an asymptomatic intracranial mass found incidentally after a motor vehicle accident. Preoperative magnetic resonance imaging revealed a well-defined dural-based lesion arising from the right anterior clinoid process that was nearly homogeneously enhancing. The radiologic diagnosis was meningioma. The mass was resected via a right pterional craniotomy with microsurgical technique. Complete resection of the mass was performed with no complications and no significant bleeding. Contrasting with the radiologic and gross tumor appearance, histopathologic examination revealed dilated vascular spaces, sclerotic vessels without intervening neural tissue, and intravascular thrombi suggesting slow blood flow-all consistent with cavernous hemangioma. CONCLUSIONS: Anterior clinoid dural-based cavernous hemangiomas are extremely rare. Although preoperative diagnosis is difficult using imaging, this etiology should be considered for any dural-based middle fossa lesion, owing to the tendency for these lesions to bleed heavily during resection in some instances.