Pituitary involvement in patients with granulomatosis with polyangiitis: case series and literature review.

GPA with pituitary involvement is a rare condition which is prone to be misdiagnosed. The aim of this study was to summarize clinical features of pituitary involvement in GPA and facilitate early diagnosis. Twelve GPA patients were retrospectively analyzed at a single hospital between 2000 and 2017. A literature review was conducted to compare previous findings with our clinical results. The incidence rate of pituitary involvement in GPA was 3.9% (12/304) without sexual predilection. Other impairments included ear, nose and throat (n = 12), oculi (n = 10), lung (n = 6), meninges (n = 4), kidney (n = 3), and skin (n = 2). Antineutrophil cytoplasmic antibodies (ANCA) were positive in all patients with lung or kidney involvement (n = 6/6), while ANCA were negative in almost all patients without lung or kidney involvement (n = 5/6). Endocrine abnormalities included central diabetes insipidus (CDI, n = 11/12) hypogonadotropic hypogonadism (n = 6/11), adrenocorticotropic hormone deficiency (n = 4/7), thyroid-stimulating hormone deficiency (n = 5/11), and growth hormone deficiency (n = 3/9). Enlarged pituitary gland (n = 6), absence of posterior hyperintense signal on T1-weighed images (n = 11) and hypertrophic cranial pachymeningitis (n = 4) were common radiological manifestations. After treatment, nine patients experienced remission but one died. Pituitary images of 3/4 patients showed size of pituitary lesions decreased. CDI was not alleviated and hypopituitarism remained in two patients. Pituitary involvement in GPA can occur at any time throughout the course of disease, including at the initial presentation. GPA could not be excluded based on negative-ANCA in patients with pituitary abnormality alone. CDI and hypogonadotropic hypogonadism are dominant endocrine abnormalities. Systemic diseases may alleviate and pituitary images may improve after treatment, though the recovery of pituitary function is rare.