A gradually progressive case of 'Pituitary incidentaloma' - Rathke's cleft cyst
I Khan1, F Hasan1, J Bashir2
1Specialty Registrar, Diabetes and Endocrinology, Musgrove Park Hospital, Taunton, Somerset
2 Specialty Registrar, Diabetes and Endocrinology, Wales Deanery
Rathke's cleft cysts (RCC) are common (found in 12-33% of autopsies of normal pituitary glands). They are usually asymptomatic and are discovered incidentally on the brain MRI scans. Their natural history is variable. Historically the Rathke's cyst are classified as benign and non-progressive and more than often (in up to 70-80% of patients) they do not grow on follow up imaging. A recent retrospective cohort study (with median follow up of 24 months) reports increase in size in up to 28% of patients with radiologically diagnosed cases of RCC. If the size of RCC is increasing, the usual presenting feature is progressive gonadotrophin deficiency and visual problems. The following case follows the later course of RCC.
This 56 year old gentleman was referred to Endocrinology outpatients in 2003 by a neurologist who 'incidentally discovered' a Rathke's cleft cyst on MRI brain done for headaches. His baseline pituitary hormone profile was normal and he was asymptomatic. Over the next few years he developed worsening lethargy, loss of libido, cold intolerance and weight gain. Repeat hormonal profile showed gonadotrophin deficiency & central hypothyroidism. MRI showed increase in the size of RCC. His case was discussed in pituitary MDT and was offered surgical decompression. He declined surgery and opted for Thyroxine and Testosterone replacement.
Over the last few months, the patient has developed worsening symptoms including tiredness, loss of appetite, retro-orbital pain, erectile dysfunction and weight loss. Repeat MRI does not show any significant increase in the size of the cyst. Hormone profile shows low 9AM Cortisol and flat response to Synacthen. He scores 24 out of 25 on AGHDA-QoL score. IGF-1 level was 15.8 nmol/l and ACTH was 11ng/l. .
This case highlights the relatively uncommon natural course of Rathke's cleft cyst with progressively worsening hypopituitarism. This also emphasises on the vital importance of long term clinical and radiological follow up of patients with Rathke's cleft cyst.