Endocrine Abstracts

Histiocytosis X is a rare disorder in which proliferating Langerhans cells can infiltrate virtually any site in the body. Bone is the most commonly affected site but endocrine involvement is frequently seen. Diabetes insipidus is the most common abnormality when there is involvement of the hypothalamic-pituitary axis.

We report the case of a 42 year old lady who presented with diabetes insipidus in 1997. MR scan of the pituitary showed absence of the posterior pituitary bright spot but was otherwise normal. A few months later she had evidence of gonadotrophin deficiency with a normal prolactin. An MR scan in 1998 showed thickening of the pituitary stalk. Dynamic testing demonstrated growth hormone deficiency (peak GH on ITT was 2.2 mU/l) and hyperprolactinaemia (Prolactin 1314 mU/l). A biopsy of the lesion was considered, but during 1999 there was regression of the infundibular lesion and by 2000 the MR scan was felt to be within normal limits. A repeat MR scan in 2002 showed mild expansion of the pituitary infundibulum, and by 2004 imaging was frankly abnormal with evidence of a suprasellar mass involving the hypothalamus and base of the infundibulum. She remained amenorrhoeic despite a trial of dopamine agonist therapy which normalised her prolactin. She then developed TSH and ACTH deficiency. She underwent subtotal resection of the pituitary stalk lesion in March 2005 and histology confirmed Langerhans cell histiocytosis (eosinophilic granuloma) of the hypothalamus/pituitary stalk. To date this lady has no evidence of multifocal disease. Although radiologically her disease showed a relapsing and remitting course her diabetes insipidus did not resolve, and anterior pituitary deficits evolved gradually.

There is a paucity of long-term follow-up studies of this condition in adults, such that there is little consensus regarding optimal treatment. We are currently considering the need for radiotherapy in this patient.