Primary pituitary granulomatosis with polyangiitis and the role of pituitary biopsy, case report and literature review.

BACKGROUND

Pituitary dysfunction (PD) in granulomatosis with polyangiitis (GPA) is a rare manifestation of the disease with an incidence of 2% and tends to occur as the disease progresses. On very rare occasions, PD can be the initial presentation of GPA. From our literature review, only 6 such cases were documented.

CASE PRESENTATION: We present a rare case of GPA in a 57-year-old female who primarily presented with PD and visual disturbance without any other systemic features of GPA. Her initial ANCA screen was negative and her MRI scan showed an enlarged pituitary gland with cystic changes. A pituitary biopsy confirmed the diagnosis and she was started on immunosuppressants. After completing her immunotherapy, her diabetic insipidus subsided and her vision markedly improved.

LITERATURE REVIEW: A literature search on Pubmed, Cochrane, Open Grey, and SciELO with keywords 'granulomatosis', 'polyangiitis', and 'pituitary' was performed. A total of 72 articles were reviewed. 6 articles were identified where PD was the presenting complaint of GPA without other systemic involvement.

DISCUSSION: Secondary hypophysitis in GPA indicates pituitary inflammation resulting from systemic disease or pituitary near-lying lesions. PD in GPA tends to occur with concomitant active disease at other sites. Headache seemed to be a common presenting feature with diabetic insipidus being the most common type of PD. Tissue biopsy is essential to confirm diagnosis. Pituitary biopsy is rarely required as other organ involvement is available for safer tissue sampling. However, in our case, pituitary biopsy had a role in confirming diagnosis and avoiding treatment delay.

CONCLUSION

PD as a primary manifestation in GPA without systemic involvement is very rare and poses a diagnostic challenge. Pituitary biopsy can aid in diagnosis, allowing prompt treatment and prevention of long-term complications of untreated GPA such as permanent pituitary dysfunction. Nevertheless, the risk and benefit of pituitary surgery in each case should be weighted.