Faculty Bibliography

Laboratory studies have established the potential for neuronal transplantation to be of benefit to patients. Experimental studies in normal animals indicate that brain implantation of neurons seems safe. Implanted neurons integrated with the host brain, sent out axonal processes to communicate with other nerve cells, released transmitters (the chemical messengers of nerve cell communication), and demonstrated typical neuronal proteins. This article discusses phase I and II trials of neuronal transplantation in humans with small strokes in critical brain locations such as the basal ganglia region. More work is needed to confirm safety and to identify optimal measures of efficacy in this setting.

OBJECT: Renal cell carcinoma is a leading cause of death from cancer and its incidence is increasing. In many patients with renal cell cancer, metastasis to the brain develops at some time during the course of the disease. Corticosteroid therapy, radiotherapy, and resection have been the mainstays of treatment. Nonetheless, the median survival in patients with renal cell carcinoma metastasis is approximately 3 to 6 months. In this study the authors examined the efficacy of gamma knife surgery in treating renal cell carcinoma metastases to the brain and evaluated factors affecting long-term survival. METHODS: The authors conducted a retrospective review of 69 patients undergoing stereotactic radiosurgery for a total of 146 renal cell cancer metastases. Clinical and radiographic data encompassing a 14-year treatment interval were collected. Multivariate analyses were used to determine significant prognostic factors influencing survival. The overall median length of survival was 15 months (range 1-65 months) from the diagnosis of brain metastasis. After radiosurgery, the median survival was 13 months in patients without and 5 months in those with active extracranial disease. In a multivariate analysis, factors significantly affecting the rate of survival included the following: 1) younger patient age (p = 0.0076); 2) preoperative Karnofsky Performance Scale score (p = 0.0012); 3) time from initial cancer diagnosis to brain metastasis diagnosis (p = 0.0017); 4) treatment dose to the tumor margin (p = 0.0252); 5) maximal treatment dose (p = 0.0127); and 6) treatment isodose (p = 0.0354). Prior tumor resection, chemotherapy, immunotherapy, or whole-brain radiation therapy did not correlate with extended survival. Postradiosurgical imaging of the brain demonstrated that 63% of the metastases had decreased, 33% remained stable, and 4% eventually increased in size. Two patients (2.9%) later underwent a craniotomy and resection for a tumor refractory to radiosurgery or a new symptomatic metastasis. Eighty-three percent of patients died of progression of extracranial disease. CONCLUSIONS: Stereotactic radiosurgery for treatment of renal cell carcinoma metastases to the brain provides effective local tumor control in approximately 96% of patients and a median length of survival of 15 months. Early detection of brain metastases, aggressive treatment of systemic disease, and a therapeutic strategy including radiosurgery can offer patients an extended survival.

Sinus histiocytosis or Rosai-Dorfman disease (RDD) is a rare idiopathic histioproliferative disorder typically characterized by painless cervical lymphadenopathy, fever, and weight loss. Extranodal, intracranial disease is uncommon. In this report the authors describe the first case of intracranial RDD treated with stereotactic radiosurgery after resection. This 52-year-old man with known RDD presented with a 7-day course of fever, headache, diplopia, left facial paresthesias, and difficulty swallowing. No cranial nerve deficits were evident on examination, but right submandibular and inguinal node enlargements were noted. On neuroimaging, the patient was found to have a homogeneously contrast-enhancing petroclival lesion with extension into the left cavernous sinus. The patient underwent a combined left petrosal craniotomy and partial labyrinthectomy with duraplasty for biopsy sampling and partial microsurgical resection of the lesion. Microscopic examination of the biopsy specimen revealed the presence of a mixed cellular population with predominant mature histiocytes consistent with RDD. The residual tumor was treated with stereotactic radiosurgery 2 months after resection. On follow-up imaging the lesion had regressed significantly, with only slight dural enhancement remaining. Microsurgical resection for histological diagnosis, followed by stereotactic radiosurgery for residual tumor represents one treatment alternative in the management of intracranial RDD in which a complete resection carries the potential for excess morbidity.