Benign nerve sheath tumor in the carotid space
The MR appearances are those of a mass in the carotid space, most likely a nerve sheath tumor.
Ultrasound biopsy showed features of benign peripheral nerve sheath tumor: the morphology is more suggestive of neurofibroma than schwannoma.
CLINICAL NOTES: Left carotid sheath mass ?Schwannoma ?Pleomorphic adenoma ?Carotid body tumor.
MICROSCOPIC DESCRIPTION: The core biopsy shows a proliferation of spindled stromal cells. They have elongated nuclei with no significant nuclear pleomorphism. The cytoplasm is ill-defined. No mitoses or necrosis is seen. The background is loose and myxomatous with thin wavy bundles of collagen. The spindled cells are S-100 positive. They are synaptophysin, smooth muscle actin and CAM5.2 negative. The features are those of benign peripheral nerve sheath tumor. The morphology is more suggestive of neurofibroma than schwannoma.
DIAGNOSIS: Left parapharyngeal mass: Benign peripheral nerve sheath tumor.