Endocrine Abstracts

Introduction: Pituitary adenomas account for 90% of sellar parasellar lesions. Inflammatory pituitary lesions are rare and can mimic tumours, creating diagnostic challenges. This case series presents five patients referred to our centre as pituitary tumour but were non-tumour inflammatory process mimicking a tumour radiologically. Two had pituitary sarcoidosis, two granulomatosis with polyangiitis (GPA), and one lymphocytic hypophysitis.

Cases: • 57-year-old man with fever, weight loss and hypopituitarism; MRI revealed sellar mass. CT scan showed hilar lymphadenopathy, suggesting sarcoidosis or lymphoma. Following rapid vision loss, intravenous methylprednisolone (neurology and respiratory input) led to vision restoration and lesion shrinkage. At 12 months, on methotrexate, patient remains well. • 49-year-old woman with acute vision loss and bitemporal hemianopia referred by ophthalmology; pituitary MRI showed large sellar lesion compressing optic chiasm. Urgent decompression and histology confirmed granulomatous lesion; lymph node biopsy revealed sarcoidosis. She was treated with high-dose steroids. • 50-year-old woman with idiopathic orbital sclerosis causing persistent headache, not responding to azathioprine. Progressively enlarging sellar lesion elevating optic chiasm, MRI features indistinguishable from adenoma. Surgical decompression confirmed lymphocytic hypophysitis. • 53-year-old male with panhypopituitarism; MRI showed atypical cystic-solid lesion. He was recently diagnosed with GPA, and systemic treatment started. The sellar lesion regressed with high-dose corticosteroids. • 44-year-old woman with worsening retro-orbital headaches and hypopituitarism; MRI showed sellar lesion, with differentials of sarcoidosis or metastasis. Severe dyspnea and an enlarging pulmonary lesion led to lobectomy which confirmed necrotizing granulomatosis; cANCA-PR3 positivity indicated GPA. Treatment with pulse cyclophosphamide therapy led to lesion shrinkage.

Conclusion: Inflammatory disorders of varying aetiology can affect the pituitary gland. Timely specialist MDT involvement can guide appropriate treatment decisions. Pituitary MRI reports in isolation can be misleading, and therefore a detailed history and assessment is mandatory in patients with rapid-onset visual loss, atypical systemic symptoms and unusual MRI findings.