ESPE Abstracts

Primary Xanthomatous Hypophysitis (XH) is the rarest histological subtype of hypophysitis. Here we describe the case of a young 9-year-old girl diagnosed with this condition. The patient presented with a four-month history of an intermittent temporal-frontal headache that became gradually worse and constant for three days prior to admission. She did not have clinical signs or symptoms suggestive of increased intracranial pressure but had mild ataxia. On admission she was febrile, lethargic and had lost 5kg of weight over five months. Her parents had noticed a sudden increase in her fluid intake eight weeks prior to this as well as nocturia. An MRI head showed a pituitary and infundibula mass extending into the suprasellar cistern and hypothalamus, measuring 23x11x17mm with compression of the optic chiasm. The patient underwent transphenoidal biopsy and partial debulking. Histology showed fragments of fibrous tissue and anterior pituitary gland, with a dense, mixed inflammatory infiltrate composed predominantly of foamy macrophages, in keeping with XH. There were no features on neoplasia. The patient had a suboptimal response to dynamic testing with glucagon (peak GH 3.1 mcg/L, peak cortisol 435 nmol/L) and remains on hormonal replacement with desmopressin, hydrocortisone, levothyroxine and growth hormone (GH). Repeat MRI five months after initial presentation shows no evidence of reoccurrence. Hypophysitis is inflammation of the pituitary gland and is thought to have an incidence of 1 in 9 million(1). XH is the rarest form of primary hypophysitis with a female predominance of 3:1. Mean age at presentation is 38 +/- 15 years for both sexes. Symptoms and imaging of hypophysitis can mimic a pituitary neoplasm (usually adenoma or craniopharyngioma). The most common presenting symptoms of hypophysitis are persistent headache and visual field deficit. Although XH has been reported to have a predilection for the anterior pituitary, it is hypothesised that diabetes insipidus occurs due to compression on the infundibulo-neurohypophysis rather than direct infiltration of the tissue. The pathogenesis of XH is poorly understood and theories relating to infectious and autoimmune causes have been described. There is evidence to suggest that XH is less responsive to medical management with steroids then other subtypes of hypophysitis and therefore surgery is often the treatment of choice. Prognosis for XH is variable from complete recovery to no improvement and often hormone replacement is required long term due to on-going endocrine deficiencies.