Endocrine Abstracts

A 69-year-old man was referred to our Pituitary Service for a 3-month history of progressive right visual loss and a finding of “pituitary enlargement” on brain MRI. He reported erectile dysfunction and his medical history included asthma, DM2 and meningitis (8 years ago). Neuro-ophthalmology review showed visual acuity 6/60, optic neuropathy, marked visual field loss with residual superonasal island in right eye, mild 6^th nerve palsy. Pituitary MRI: infiltrative lesion within the fossa extending to the right over the anterior clinoid process affecting the dura related to the dorsum sellae and the optic canal and overlying the planum sphenoidale, pituitary stalk thickening and a separate well-defined 8 mm mass in the left side of the fossa (presumed microadenoma). He had mild hyperprolactinaemia and hypogonadotropic hypogonadism; IGF-I, TSH and ACTH reserve were normal. There was no evidence of diabetes insipidus. CSF cytology suggested inflammatory process involving B- and plasma cells. PET-CT revealed intense uptake activity in two pancreatic masses and in para-aortic, aortocaval and retroperitoneal lymph nodes. EUS-biopsy of one pancreatic lesion showed evidence of fibrosis, significant excess of plasma cells and IgG and IgG4 expression. Serum IgG4 levels were also increased [9.20 g/l (0-1.3)]. IgG4-related disease was diagnosed. Prednisolone was initiated (four-week course; 30 mg with gradual tapering to 5 mg daily) leading to full recovery of his right visual field and acuity, shrinkage of the sellar and pancreatic lesions and lymph nodes, and decrease in serum IgG and IgG4 levels. The presumed microadenoma had remained unchanged. This is an unusual case of rare sellar pathology coinciding with a pituitary adenoma. Although hypophysitis is the most common manifestation of IgG4-related disease in the sellar region, in our patient, dural involvement was also present. This case also highlights the importance of broad differential diagnosis when approaching pituitary abnormalities on imaging.