CT and MRI imaging of mass in the carotid space: a pictorial review.

The carotid space is a paired anatomical space defined by the carotid sheath, where a range of diseases may occur, including primary or secondary tumors, inflammatory conditions, congenital anomalies, vascular disorders, and traumatic lesions. Both computed tomography (CT) and magnetic resonance imaging (MRI) enable detailed evaluation of lesions within the carotid space, offering a large field of view. Masses are the most commonly encountered imaging findings, most of which can be characterized on CT and/or MRI by their location, enhancement pattern, and relationship to adjacent vessels. Certain lesions may mimic masses arising within the carotid space, and differential diagnosis typically relies on careful assessment of adjacent muscles, fat planes, and vessels. This paper provides a review of pathological entities manifesting as carotid space masses, encompassing both benign and malignant neoplasms as well as non-neoplastic conditions. Key discussed entities include: schwannomas, neurofibromas, malignant peripheral nerve sheath tumors (MPNSTs), neuroblastomas, paragangliomas, aneurysms, pseudoaneurysms, arteriovenous fistulas (AVFs), venous malformations, nasopharyngeal carcinomas, meningiomas, branchial apparatus anomalies, and pathological conditions of the deep cervical lymph node chain. The manuscript further delineates critical differential diagnoses requiring careful consideration, including tumors originating from the parotid gland's deep lobe, masses arising from the prevertebral space, and lipomatous lesions. A thorough understanding of the intricate anatomy of the carotid space, combined with the ability to navigate a wide range of differential diagnoses, is crucial for making accurate clinical diagnoses.