[Classification of Clinical Syndromes Associated with Skull-Base Metastasis in the MR Era]

Skull-base metastases frequently cause progressive ipsilateral disturbances of cranial nerves or pain, resulting in poor quality of life in patients with cancer. Magnetic resonance(MR)imaging is the method to detect skull-base metastases, which demonstrates focal lesions of low-intensity signal and enhancement on T1-weighted MR images.

We reviewed clinical data and MR images from 127 patients with skull-base metastases diagnosed at Shizuoka Cancer Center Hospital between August 2012 and November 2017.

The most common primary site was the lung(44 patients), followed by the breast(34), colon(8), and prostate(8). The interval from diagnosis of the primary tumor to skull-base metastasis ranged from 0 to 276 months(median, 9 months). The interval was shortest with lung cancer(median, 0 month), and longest with carcinoma of the liver(median, 81 months). The most commonly affected site was the clivus(74%), followed by the petrous(35%), and the occipital condyle(18%). We classified 55 symptomatic patients into 6 clinical syndromes: orbital(18%), parasellar(7%), middle cranial fossa(24%), jugular foramen(7%), and occipital condyle(15%), described by Greenberg, and a new entity "clivopetrosal" syndrome presenting diplopia due to abducens palsy(20%). Of 47 patients who underwent irradiation, 29 patients(62%)achieved relief of their symptoms. Median overall survival after diagnosis of a skull-base metastasis was 7 months. Male sex and colon cancer were associated with poor prognosis.

When a cancer patient presents with new-onset cranial nerve palsies or craniofacial pain, physicians need to identify skull-base metastases for prompt radiotherapy.