Sixty seven year old gentleman presented to eye clinic with blurring of vision in the left eye for 2 weeks. Patient was seen by Ophthalmologist and discharged home. Presented 3 weeks later with headache and blurring of vision. On examination no perception to light in the left eye and bitemporal hemianopia.
His past history includes carcinoma prostate, diagnosed a year ago and had surgery and Radiotherapy. His recent PSA was normal. Bones scan showed no evidence of bony metastasis.
His MRI brain showed mass lesion within the pituitary fossa with chiasmal compression. The MRI was reviewed by NeuroRadiologist and the diagnosis was pituitary macro adenoma. His CT chest and abdomen was normal.
His prolactin was 1059 mU/l. His TSH was 0.81 mU/l, FT4 of 7.7 pmol/l. GH was <0.1 U/l, and cortisol was 35 nmol/l suggestive of non functioning pituitary macro adenoma.
He underwent Trans sphenoidal resection of adenoma. Unfortunately only sub total resection was achieved. Intra operative smear has been reported as possible meningioma. Repeat MRI (4 days post-op) showed significant residual tumour with chiasmal compression. He underwent left eyebrow craniotomy and debulking of residual tumour.
Histology showed metastatic adeno carcinoma and immuno phenotype suggestive of Prostatic primary. His case was discussed in the MDT and the plan was to give Cranial Radiotherapy in view of metastasis.
Reviewed in the clinic after 2 months. His vision has improved significantly visual field was normal to confrontation method.
This case is very interesting due to the rarity of brain metastasis in Carcinoma of prostate. Usually it is <1%. Brain metastasis signifies late stage of the disease and the mean survival is 9 months. Only three cases have been reported in the literature so far. Endocrinologist should consider a metastatic lesion in the differential diagnosis of a non-functioning pituitary tumour.