Perineural spread of malignant melanoma of the head and neck: clinical and imaging features

Abstract

BACKGROUND AND PURPOSE:Extension of malignant melanoma along cranial nerves is a little-known complication of malignant melanoma of the head and neck. We describe the clinical and MR imaging findings of perineural spread of malignant melanoma to cranial nerves, emphasizing that this entity occurs more commonly with desmoplastic histology and may have a long latent period following primary diagnosis.METHODS: At two institutions, we identified and retrospectively reviewed eight cases of malignant melanoma of the head and neck that had MR imaging evidence of perineural spread of disease. All patients underwent confirmatory tissue sampling.RESULTS: Seven patients had melanomas of the facial skin or lip, and one patient had a primary sinonasal lesion. By histopathology, these melanomas included five desmoplastic, two mucosal, and one poorly differentiated melanotic spindle-cell tumor. All patients developed symptomatic cranial neuropathy an average of 4.9 years from the time of initial diagnosis. MR imaging demonstrated postgadolinium enhancement of at least one branch of the trigeminal nerve in all cases and of at least one other cranial nerve in five cases. Other findings included abnormal contrast enhancement and soft tissue thickening in the cavernous sinus, Meckel's cave, and/or the cisternal segment of the trigeminal nerve.CONCLUSION: Although perineural spread of disease occurs most commonly with squamous cell carcinoma and adenoid cystic carcinoma, malignant melanoma must also be included in this differential diagnosis, particularly if the patient's pathology is known to be desmoplastic. Similarly, any patient with malignant melanoma of the head and neck who undergoes MR imaging should receive an imaging assessment focused on the likely routes of perineural spread.

Visualization of the Peripheral Branches of the Mandibular Division of the Trigeminal Nerve on 3D Double-Echo Steady-State with Water Excitation Sequence

“…Because the auriculotemporal nerve is often involved in the perineural spread of malignancy, 3,10,24 our results suggest that the 3D-DESS-WE sequence is a promising method for evaluating perineural tumor spread. The main explanation for the poor detection of small branches is that the visualization depends on the size of the nerve.…”

“…14,15 Without the high-signal background from the CSF, however, heavily T2-weighted imaging has not proved to be very useful in visualizing the extracranial segments of the cranial nerves. Detecting the remaining peripheral segments can be achieved with pre-and postcontrast high-resolution 3D T1-weighted images (gradient-recalled acquisition in steady state, fast-spoiled gradient recalled-echo, or MPRAGE) with and without fat suppression, [9][10][11][12][13]16,18,23 but detecting the entire course of the extracranial branches of the cranial nerves is still very challenging. The 3D-DESS-WE sequence, commonly used in musculoskeletal imaging, was recently applied for visualization of the intraparotid facial nerve and is quite successful.…”

“…All of these pathologic etiologies have the potential to impact clinical outcomes significantly and may contribute to significant morbidity and quality of life. 3,10,23,24 An in-depth understanding of the anatomy and normal course of the extracranial nerves is required to make the diagnosis of many of these pathologies, and more sophisticated and dedicated high-resolution MR images for peripheral cranial nerve imaging are expected to enter and influence clinical practice. The widespread uses of volumetric CT scanners and high-field MR imaging scanners and recent advances in MR imaging technology have provided opportunities to obtain high-resolution images of the cranial nerves.…”

Malignant Granular Cell Tumor of the Skull Base

“…32 Perineural extension of head and neck tumors is well known and most commonly seen in squamous cell carcinomas and adenoid cystic carcinomas. 33,34 However, this pattern of spreading is also seen in GCTs, 35 desmoplastic fibromas, 36 malignant melanomas, 37 and nasopharyngeal carcinomas. 38 In most cases, the tumor spreads directly in the perineural or the endoneural tissue planes along the path of least resistance.…”

Imaging Lesions of the Cavernous Sinus

“…MR imaging features of perineural tumor spread include nerve enlargement and enhancement and foraminal enlargement and destruction (Fig 10). [36][37][38][39][40][41][42] Lymphoma and Leukemia As with metastases, lymphoma and leukemia reach the CS by direct extension from a primary lesion or from hematogenous spread. MR imaging may show infiltrative lesions of the skull base invading the CS without arterial narrowing.…”