Incidental finding of metastatic prostatic adenocarcinoma of cerebellopontine angle presenting as acoustic neuroma: A case report and review of literature

INTRODUCTION: Brain metastases from carcinoma of prostate are rare and only few cases with brain metastases preceding the diagnosis of carcinoma of prostate have been reported in the literature. Lesions of brain metastasis from prostate cancer had a large variety of imaging presentations and it is very difficult to distinguish them from the other types of brain occupying lesions. We report one case of metastatic prostatic adenocarcinoma of cerebellopontine angle presenting as acoustic neuroma, as the first clinical evidence of metastatic carcinoma of the prostate. PRESENTATION OF CASE: The 57-year-old male presented to the neurology clinic complaining of dizziness accompanied by right tinnitus, he was proposed to be diagnosed with acoustic neuroma, and the tumor resection was performed later in our neurosurgery department. The postoperative histopathological and immunohistochemical (IHC) examinations revealed a cerebellar pontine angle metastatic adenocarcinoma, which was then confirmed as prostate cancer metastasis. The patient refused surgical castration and only agreed to conservative treatment. The patient's condition continued to deteriorate, and he died 12 months after the initial presentation. DISCUSSION: Brain metastasis is rare in prostate cancer, which accounts for only 0.2 % to 2 % of all brain metastases. Intracranial metastasis as the first clinical symptom of prostate cancer is extremely rare. In our article, we report the VIIIth and VIIth cranial nerves palsy for the first time, caused by brain metastases from prostate cancer, with symptoms similar to an acoustic neuroma. Prostate cancer most commonly spreads to the bones, including the skull, Cranial nerve palsy is caused by extensive invasion of the skull base. The serum PSA level is considered the most valuable tool to monitor the disease progression of patients with prostate cancer metastasis. A high PSA level significantly increases the tendency of prostate cancer to metastasize to the brain. A high Gleason score is believed to help determine the risk and likelihood of brain metastases in patients with prostatic carcinoma. CONCLUSION: In our case, we initially report the VIIIth and VIIth cranial nerve palsy, mimicking an acoustic neuroma, caused by metastatic prostate carcinoma. For early diagnosis, the prostate should not be neglected as a possible source of the metastases in male patients presenting with brain metastases. High prostate specific antigen (PSA) level and high Gleason score can be useful parameters for the prediction of brain metastasis from prostate cancer. The PSA should play a vital role in distinguishing metastatic prostate carcinoma in male patients.