Carcinoma of the prostate: brain stem metastasis as the only site of spread.

AIMS AND BACKGROUND: Metastasis to the brain from prostate carcinoma is a rare event; it is reported in less than 4% of postmortem examinations. The prevalence of cases detected antemortem is even smaller, and the prevalence of brain stem metastasis as the only site of metastasis has been reported in only two other cases. METHOD: The authors present a third such case. RESULTS: A 55-year-old man, treated for an adenocarcinoma of the prostate (prostatectomy and radiotherapy), started to complain of facial expression disturbances and headaches 2 years later. Physical examination showed a left VII cranial nerve palsy. MRI showed an enhancing mass in the pons. Total body CT was negative. The patient was treated with a course of whole-brain and brain stem radiotherapy following stereotactic biopsy. Four months after radiotherapy, the neurological symptoms had disappeared and the patient died of a myocardial infarct. The systemic disease was still clinically silent. CONCLUSION: Our case involved only brain stem metastasis, probably implicating Batson's direct route of the paravertebral venous pathway.