Neurotrophic Spread of Malignancy. Clinical Aspects and Diagnostic Options

Purpose: The vast majority of pathology enters the cavernous sinus from local extension (meningiomas, schwannomas) and metastasize via the bloodstream. An uncommon but not rare source of malignancy within the cavernous sinus is spread of malignancy along the branches of the trigeminal nerve. Certain tumors, particularly squamous cell carcinoma and adenoid cystic carcinoma have a propensity to spread neurotrophically to the cavernous sinus. Since inflammatory lesions can mimic neurotrophic spread, specific diagnosis can be essential.

Materials and Methods: A retrospective study of a series of 18 patients seen at the University of Virginia with neurotrophic spread of spread of carcinoma are analyzed for pathology presenting with symptomatology and diagnostic options.

Results: Probably the most common preliminary symptom in these patients was sensory loss, often associated with pain, in the distribution of the trigeminal nerve. This was followed by variations of cranial nerve palsies, particularly with ophthalmoplegia involving the III, IV, and VI cranial nerves. Imaging studies typically revealed enlargement within the cavernous sinus, occasionally spreading along the root of the trigeminal nerve into the pons. Occasionally, the distal branches of the trigeminal nerve could be seen to be enlarged or enhancing. Surgical procedures to make a definitive diagnosis included biopsy of the infraorbital nerve within the floor of the orbit or roof of the maxillary sinus, and biopsy of the supraorbital nerve when involved. A direct translateral orbital approach also permitted larger pieces of tissue for marker studies. Patients were subsequently treated with fractionated radiation therapy, which often slowed growth.

Conclusions: Neurotrophic spread of cancer is an uncommon but not rare source of pathology involving the cavernous sinus and skull base. Certain tumors including squamous cell carcinoma and adenoid cystic carcinoma (less commonly melanoma and lymphoma) often spread neurotrophically. Sensory loss and multiple cranial nerve palsies are a common presentation. Imaging studies including T1 weighted images without fat sat often permit detection of subtle changes involving the branches of the trigeminal nerve. Peripheral biopsy, fine needle cytology or transorbital approach can often provide tissue for a definite diagnosis without the necessity of a craniotomy.