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 tumour.

Ultrasound biopsy confirmedshowed features of benign peripheral nerve sheath tumour: the presencemorphology is more suggestive of neurofibroma than schwannoma.

Technique:

Multiplanar multi sequence imaging including postcontrast fat saturated axial and coronal sequences have been obtained.

Comparison:

MRI dating back to 2011.

Findings:

The previously described left carotid space lesion, with imaging features consistent with a benign nerve sheath tumour, is again demonstrated. There is evidence of gradual growth when compared to imaging dating back to 2011; today it measures 5.2 x 3.7 x 4.5 cm, compared to 4.7 x 3.4 x 3.0 cm in 2011three years ago. Otherwise it is unaltered in appearance, again demonstrating prominent high T2 signal peripherally and central low T2 signal, a feature which favours a neurofibroma/schwannoma. It remains well-circumscribed, no evidence of direct invasion, and no lymph node enlargement.

The internal carotid artery is displaced medially, and there is narrowing of the oropharynx. The internal jugular is displaced postero-laterally, compressed between the mass and the deep lobe of the parotid.

Conclusion:

Continued Continued gradual enlargement of the left carotid space benign nerve sheath tumour.

The procedure was discussed at length with the patient and her husband, informed consent obtained.

Using ultrasound guidance and sterile technique the skin was infiltrated near the angle of the mandible, and an 18 gauge core biopsy needle passed into the carotid sheath mass.

Manual deployment of a 10 mm core biopsy was performed, carefully avoiding arterial structures nearby.

Single sample obtained appeared approximately 4 mm long, and this was sent in formalin for histology.

The patient was recovered in the department, and no immediate complication noted.

CLINICAL NOTES:

Left Left carotid sheath mass ?Schwannoma ?Pleomorphic adenoma ?Carotid

body body tumour.

MACROSCOPIC DESCRIPTION:

"Left parapharyngeal mass": A soft cream 1mm core biopsy, 10mm long.

A1 A1. Shallow trimmings. (OWP)

MICROSCOPIC DESCRIPTION:

The core biopsy shows a proliferation of spindled stromal cells. They

have have elongated nuclei with no significant nuclear pleomorphism. The

cytoplasm cytoplasm is ill-defined. No mitoses or necrosis is seen. The

background background is loose and myxomatous with thin wavy bundles of collagen.

The The spindled cells are S-100 positive. They are synaptophysin, smooth

muscle muscle actin and CAM5.2 negative. The features are those of benign

peripheral peripheral nerve sheath tumour. The morphology is more suggestive of

neurofibroma neurofibroma than schwannoma.

DIAGNOSIS:

Left Left parapharyngeal mass: Benign peripheral nerve sheath tumour.