Panhypophysitis and infundibulitis associated with granulomatosis with polyangiitis.

Summary: A 39-year-old woman presented with a 5-year history of severe intermittent headaches, rhinitis, hemoptysis, unintentional weight loss of 40 kg over a year, and unilateral vision loss. Then, she noticed polyuria, amenorrhea, muscle weakness, and cold intolerance. Diagnosis of granulomatosis with polyangiitis (GPA) was confirmed with elevated c-ANCA levels and PR3-positive antibodies. Physical examination revealed hypotension, absence of pubic and axillary hair, and classical signs of hypothyroidism. The patient reported multiple previous hospitalizations due to episodes of hypernatremia, hypotension, and hypoglycemia. The biochemical evaluation showed early signs of chronic kidney disease and central adrenal, thyroid, and gonadotropin deficiencies. Pituitary MRI revealed a heterogeneous pituitary gland with peripheral enhancement, central necrosis, and extension to adjacent structures, as well as the absence of posterior pituitary bright spot on T1-weighted imaging. A diagnosis of GPA with pituitary involvement was established. Remission therapy with corticosteroids and rituximab was started. After disease control, pituitary hormonal deficiencies persisted, requiring long-term hormone replacement therapy.

Learning points: Pituitary involvement in cases with GPA is a rare manifestation frequently misdiagnosed. It is important to be aware of hypophysitis as a GPA activity complication that warrants a prompt diagnostic approach and treatment. The pathophysiology of hypophysitis may be mediated by a granulomatous lesion or due to vascular damage. Pituitary dysfunction in GPA may occur at any moment, as an initial manifestation or as a concomitant syndrome together with other organ compromise. Deficiency of arginine vasopressin and central hypogonadism are the most frequent pituitary hormonal alterations. Pituitary dysfunction usually persists despite remission of systemic activity, requiring long-term hormone replacement therapy and surveillance.