Endocrine Abstracts

A 57-year-old gentleman presented with bilateral painless submandibular swelling, and flu like symptoms. A biopsy from the enlarged submandibular gland showed chronic sclerosing sialadenitis with lymphocytic infiltration. Immunohistochemistry showed plasma cells positive for CD79a and IgG4, and a combination of CD4 and CD8 positive lymphocytes. IgG4 levels were significantly raised (3.16 g/l, NR <1.3 g/l). A diagnosis of IgG4 syndrome was made. Chest and abdominal CT imaging did not reveal involvement of other organ systems. Treatment with a reducing dose of oral prednisolone over 6 months resulted in a reduction of IgG4 levels to 2.27 g/l but no significant change in the ultrasound appearance of the submandibular glands. A 6-month trial of hydroxychloroquine was also ineffective. IgG4 levels have increased over time (IgG4 >3.44 g/l, Sept 2014).

In October 2014 the patient complained of recent inset of severe thirst and frequent urination. Initial investigations showed serum and urine osmolalities of 309 and 116 mOsm/kg respectively. A subsequent water deprivation test confirmed a diagnosis of central diabetes insipidus. Anterior pituitary function was normal apart from hypogonadotrophic hypogonadism (LH 2.7 U/l, FSH 1.8 U/l, and testosterone 4.4 nmol/l). MR imaging showed a normal pituitary gland but with abnormal thickening and enhancement of the infundibulum. A diagnosis of IgG4-related hypophysitis was made and the patient responded well to desmopressin. Testosterone replacement is currently under consideration. Hypophysitis is a rare complication of IgG4 syndrome. A case series from Japan¹ reported a male predominance, with variable involvement of anterior and pituitary hormone systems. Diabetes insipidus is the most common endocrine complication. There is a lack of trial data to inform the treatment of IgG4 syndrome. Glucocorticoid therapy remains the first-line of treatment but has not proved effective in this case. He is now being considered for a trial of low dose methotrexate. His anterior pituitary function will be monitored over time to determine the extent of disease progression.

Reference: 1. Shimatsu et al. 2009 Endocr J 56 1033–1041.