Delayed pituitary apoplexy in patient with advanced prostate cancer treated with gonadotrophin-releasing hormone agonists.

Gonadotrophin-releasing hormone agonists (GnRHAs) are used in many clinical conditions, particularly prostate cancer. There have been a few case reports of apoplexy from a previously undiagnosed pituitary tumour, occurring within hours to days of initiation of GnRHA therapy. We report a case of delayed onset pituitary apoplexy following GnRHA therapy. A 71-year-old man presented three weeks after onset of headache and vision loss. On examination, he was blind in the right eye with an intact nasal field of vision in the left eye. Two months before presentation, he had a subcutaneous GnRHA (Goserelin) implant for treatment of locally advanced prostate cancer (Gleeson 4+3). An MRI scan revealed a large sellar/suprasellar mass. His follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels were grossly elevated. A trans-sphenoidal endoscopic decompression of the pituitary tumour was performed. His vision improved post-operatively and his FSH, LH, testosterone, prostate specific antigen (PSA) levels returned to normal levels. Histopathologic studies revealed a pituitary adenoma, which stained positive for FSH and LH. The prostate cancer management was changed to an anti-androgen agent and a GnRH antagonist. This case demonstrates that pituitary apoplexy can develop up to eight weeks after the initiation of treatment for prostate cancer with GnRHAs.