Paraneoplastic neurological and hematological syndromes associated with prostate cancer.

Paraneoplastic neurological syndromes are defined as the remote effects of cancer on the nervous system. Here we report a 68-year-old man who initially presented with worsening paresthesia in the lower extremities. Although the culprit lesion remained to be identified, he coincidentally had diagnosis of prostate cancer by an annual prostate-specific antigen examination. Leukocytosis and elevated granulocyte colony-stimulating factor in serum were also detected. Neurological symptoms and leukocytosis improved after initiation of androgen-deprivation therapy followed by external beam radiotherapy. A total of 9 months after treatment, the patient showed no evidence of cancer recurrence or neurological signs. Paraneoplastic neurological syndromes are rare in prostate cancer and therefore have received little attention. We should be aware that when paraneoplastic neurological syndromes occur, they usually occur as the first sign of or during progression of prostate cancer. Furthermore, we should take into account the existence of malignancy when the cause of neurological symptoms cannot be specified.