Clinical History
A 42 year old male came with giddiness and imbalance since 5 days. He had also experienced headache since a month which had worsened since last 5 days. MRI brain was requested for further evaluation. Patient had no other complaints.
Imaging Findings
Initial MRI showed a well defined heterogenously enhancing mass in inferior vermis. Mild perilesional edema was seen in both the cerebellar hemispheres with compression of 4 th ventricle. In view of age of patient and solitary lesion; metastasiswas suspected . Patient for worked up to search for primary tumour which was renal cell carcinoma. Subsequently he was operated simultaneously for solitary cerebellar metastasis and nephrectomy was done. The patient subsequently underwent whole brain radiation.
Follow up MRI after one month post radiation revealed residual tumour in inferior vermis.
Multiple nodular enhancing deposits were noted involving leptomeninges around the operative site.
Multiple enhancing nodules were seen in extramedullary intradural location throughout the spinal canal. Multiple lesions were also seen on the surface of cervical cord. Single intramedullary lesion was seen with extensive cord edema.
Discussion
Brain metastases outnumber primary brain lesions and are the most prevalent intracranial tumors.Typically, patients present with brain metastases after a primary tumor has been diagnosed. However, synchronous presentation of both a primary and metastatic lesion, or even presentation of the metastasis alone, without an obvious primary lesion have been observed.[1]
Common presenting symptoms are cognitive impairment, hemiparesis, seizures, gait ataxia, aphasia, and visual disturbances.
MRI with contrast is the modality of choice for its diagnosis.
The use of surgery in the treatment of brain metastases is controversial. Surgery for cerebral metastasis prolongs patient survival and improves the quality of life in patients suffering from mass effect. Surgery has been recently perceived as a standard therapy for single cerebral metastasis, followed by WBRT(Whole Brain Radiotherapy). [2]
Stereotactic radiosurgery (SRS) alone can provide a similar survival advantage, but when used as postoperative adjuvant therapy, patients experience extended survival times. Furthermore, surgery remains the only treatment option for patients with life-threatening neurological symptoms, who require immediate tumor debulking as SRS will not immediately relieve mass effect compression or CSF obstruction as caused by a metastatic lesion. Another significant indication for the use of surgery over SRS is presence of radioresistant tumor (renal cell carcinoma, sarcoma, melanoma).
Leptomeningeal carcinomatosis is a devastating complication of malignancy, which is often associated with poor quality of life and dismal prognosis. Intraoperative tumor spill, has long been suggested to provoke cancer dissemination. The increased incidence of leptomeningeal spread(LMS) in posterior fossa metastasis is attributed to a greater chance of CSF exposure or ventricle opening during the resection.
En bloc resections are particularly useful in resecting posterior fossa metastases and lesions in contact with the CSF pathway.However, piecemeal resection may be unavoidable in some situations, as in cases where the tumor is adherent to or infiltrating eloquent brain regions, or when the lesion is extremely friable.
In study by Ahn et al; postoperative WBRT (given either immediately postoperatively or after recurrence) failed to show any protective effect for the development of LMS. Our case also showed similar result.
Differential Diagnosis List
Solitary vermian metastasis from renal cell carcinoma with postoperative leptomeningeal spread
Hemangioblastoma
Pilocytic astrocytoma
Final Diagnosis
Solitary vermian metastasis from renal cell carcinoma with postoperative leptomeningeal spread
