Endocrine Abstracts

Granulomatosis with Polyangitis (GPA) typically affects the lungs, kidneys and ENT system. Pituitary involvement is extremely rare, affecting less than 1% of all cases. The most common pituitary manifestations are secondary hypogonadism and Diabetes Insipidus (DI).Corticosteroids and immunosuppressive agents represent mainstay of medical management. Treatment needs to be initiated promptly and individualised according to clinical response.

Case 1: A 54-year-old woman presented in 2017 with sinusitis, haemoptysis and cavitating lung lesions on imaging. The clinical presentation and strongly positive c-ANCAs and Proteinase 3 (PR3) antibodies led to a diagnosis of GPA. Disease remission was achieved with Corticosteroids, Cyclophosphamide and Mycophenolate (MMF). She re-presented in August 2019 with blurring of vision and headache. Humphrey field testing revealed a bitemporal visual field defect. Secondary hypothyroidism, hypogonadism and DI were confirmed biochemically. A pituitary MRI showed a suprasellar mass with increased peripheral signal enhancement and chiasmal compression. The pituitary/vasculitis MDT felt that the pituitary lesion was likely inflammatory in nature. An increase of prednisolone to 60 mg led to a reduction in the size of the pituitary lesion. She subsequently received two doses of Rituximab together with Cyclophosphamide and the plan is the wean her steroids.

Case 2: A 50-year-old woman presented with haemoptysis and multiple cavitating lung lesions on imaging in 2016. She tested strongly positive for c-ANCA with high PR3 titres. A diagnosis of pulmonary GPA was made. She was started on Prednisolone 60 mg and both Cyclophosphamide and Rituximab. Unfortunately, she developed an allergic reaction to the latter. In 2018, she experienced intermittent headaches. A pituitary MRI revealed an enlarging suprasellar mass with peripheral enhancement, abutting the optic chiasm. Visual fields remained normal. She proceeded to a pituitary biopsy as per the recommendation of the pituitary/vasculitis MDT. This confirmed lymphocytic hypophysitis. She later developed sinusitis and pituitary insipidus confirmed on water deprivation testing. Her most recent pituitary MRI showed an increase in the volume of the pituitary lesion, with a change in its shape suggesting worsening pituitary GPA. PR3 antibody levels were rising. Prednisolone was increased to 60 mg and Azathioprine replaced by MMF. Management of pituitary GPA remains challenging. Both patients developed a pituitary flare whilst their disease had been in remission otherwise. Corticosteroids are important in remission induction, but cause significant morbidity. The response to conventional steroid-sparing agents remains variable and the role for Rituximab in pituitary GPA is to be determined in clinical studies.