[Sphenoid metastasis mimicking a meningioma as the initial feature of adenocarcinoma of the prostate].

Introduction: Presentation of adenocarcinoma of the prostate as an intracranial metastasis is uncommon. This metastasis tends to be seen in the sphenoid bone, and in this case it is difficult to differentiate radiologically from a meningioma. Because this cancer is treatable, the differential diagnosis must be resolved as soon as possible.
Clinical Case: A 72 year old man presented with a rapidly progressive left parasellar syndrome. On neuroimaging there was a tumour at the level of the left lesser wing of the sphenoid, which was isodense and iso-intense and also showed homogeneous uptake of contrast material. On angiography the circulation was pathological with homogeneous delayed filling. The initial diagnosis was meningioma of the lesser wing of the sphenoid. Months later the patient complained of bone and respiratory problems. At this time plain chest X-ray was compatible with carcinomatous lymphangitis. Therefore, tumour markers were studied and for the first time the specific prostatic antigen was investigated and found to be raised. Although there were no symptoms of prostatism, per rectum there was a malignant prostatic mass. In spite of complete hormone block, his illness followed an unfavorable course. At necropsy there was adenocarcinoma of the papillary prostate and a metastasis in the left lesser wing of the sphenoid.
Conclusions: In elderly men, detection of a sphenoid tumour, which radiologically may appear to be a meningioma and although prostatism has not been diagnosed, the possibility of prostatic metastasis should be considered. Per rectum examination and specific prostatic antigen determination should be done in these patients.