Endocrine Abstracts

A 68-year-old gentleman with hypertension and diet-controlled type 2 diabetes presented in September 2015 with weight loss, fatigue, low libido and cold intolerance.

Blood results demonstrated secondary hypothyroidism (TSH 0.59 mU/l (reference 0.35–5.00), free T4 8.3 pmol/l (ref 9.0–21.0)), hypogonadotrophic hypogonadism (testosterone 1.0 nmol/l (ref 10.0–36.0), FSH 1.5, LH 1.1) and a modestly elevated prolactin (795 mU/l (ref <400)). Short synacthen test revealed baseline cortisol of 87 nmol/l rising to 376 nmol/l after 30 minutes. Serum angiotensin converting enzyme and ferritin were normal. MRI pituitary with contrast revealed normal appearances of the pituitary gland.

The working diagnosis was panhypopituitarism of unclear aetiology. He was treated with oral hydrocortisone, levothyroxine and Testogel, with good symptomatic improvement.

Six weeks later, he re-presented with a swollen left leg. Doppler ultrasound excluded DVT. To exclude underlying malignancy, CT thorax, abdomen and pelvis was performed. This confirmed extensive inflammatory-looking tissue within the abdomen and pelvis, involving the left ureter and iliac vessels resulting in hydroureteronephrosis. Radiological appearances and subsequent biopsy were in keeping with retroperitoneal fibrosis. Serum IgG4 levels are pending.

He has been commenced on high-dose oral prednisolone and awaits repeat imaging.

Immunoglobulin G4-related disease is a collection of disorders characterized by tissue infiltration with IgG4-positive plasma cells and CD4+T lymphocytes, accompanied by fibrosis. It may affect one or more organs, and in this case manifests as retroperitoneal fibrosis and hypophysitis. Lymphadenopathy is often present, alongside weight loss in those with multiorgan disease.

Retroperitoneal fibrosis has been associated with hypopituitarism in a number of case reports; the relationship is poorly understood but the underlying pituitary disease is thought to be related to hypophysitis.

Diagnosis is based on characteristic histopathological features on biopsy. Serum levels of IgG4 are elevated in 60–70% of patients. Most patients respond well to glucocorticoid treatment.