[A case of malignant paraganglioma presenting with skull metastases]

A non-functioning paraganglioma is usually benign, however, it may cause distant metastases. There is no histological appearance for the diagnosis of malignancy or absolute criteria for predicting malignant potential. Bony metastases from paraganglioma are known to occur, but, skull metastases are very rare. We report a case of intracranial metastases from a renal paraganglioma. A 61-year-old male presented with temporal headache and exophthalmos on the left side. Seven years prior, he underwent surgery to remove a mass in the right renal hilum, which was diagnosed as renal cell carcinoma at that time. Computed tomography and magnetic resonance imaging showed a ring-like enhanced mass in the left middle fossa, which destroyed the sphenoid bone and the lateral wall of the orbit. Another osteolytic lesion was revealed in the occipital bone. The fragile tumor was totally resected. Histopathological study revealed the Zellballen pattern with extensive coagulation necrosis. No apparent nuclear atypia or mitosis were present. Immunohistochemistry showed reactivity for synaptophysin and chromogranin A in the tumor cells. Review of the surgical specimen of the previously resected renal tumor revealed the same pathological and immunohistochemical findings as those of chief cells in the middle fossa tumor. Thus, this tumor was diagnosed as a malignant paraganglioma metastasized from renal paraganglioma. After six cycle chemotherapy with cyclophosphamide and vincristine, his condition was stable for two years, however, he died four years after the diagnosis of malignancy.