Parasellar meningioma : an insidious impersonator

Abstract

The patient is a 45 year old gentleman known case of HIV seropositivity (well-controlled, undetectable viral load) and polycystic kidney disease, who was referred to our Endocrine clinic by the Infectious disease specialists in view of a 4 year history of erectile dysfunction (ED – preceded diagnosis of HIV) and a low testosterone level. During the first consultation, the patient reported occasional lethargy and long term nausea which was attributed to his retroviral treatment. He denied any vomiting or headaches. The only neurology of note was right abducens nerve palsy, stable since diagnosis 10 years prior. (Magnetic resonance (MR) imaging of the head at time of initial presentation had been reported as showing no positive findings.) Clinical examination was otherwise unremarkable. A full pituitary profile taken after the initial endocrine consultation was suggestive of hypopituitarism (low serum total testosterone, cortisol and free thyroxine concentrations. In light of the biochemical investigations, an urgent MR pituitary was organised which showed an extensively infiltrating right parasellar lesion, which was most in keeping with a parasellar meningioma. A retrospective evaluation of his past imaging studies demonstrated that the lesion had already been present in the first MR study. Formal visual perimetry was overall normal. A standard short synacthen test (SST) performed after the results of the initial pituitary profile showed adequate cortisol response. He was subsequently started on testosterone and levothyroxine replacement therapy which brought about an improvement in his hypopituitary symptoms and biochemistry. At this point, definitive treatment of this gentleman’s meningioma is still being carefully evaluated within a multi-disciplinary team. Given the size and the location of the meningioma and the possible inherent complications of surgery, radiotherapy appears to be the favoured treatment option. This case report highlights the diagnostic pathway in the investigation of hypopituitarism whilst bringing to the fore mimickers of pituitary tumours.