Neuroendocrinology and Pituitary

SAT-062 - A Case of Igg4-Related Hypophysitis, Concurrent with Pachymeningitis and Relapsed Igg4-Related Autoimmune Pancreatitis

Saturday, June 13, 2026

9:30 AM - 4:30 PM CT

Location: ENDOExpo; Poster Floor

Abstract Poster Presenter(s)

YASUNORI FUJITA, MD., PhD

Akashi, Hyogo prefecture, JAPAN

Co-Author(s)

HI

Hiroto Iizuka, MD.

Hyogo Prefectural Kakogawa Medical Center, Department of Diabetes and Endocrinology
Kakogawa, Japan
MM

Masashi Masuda, MD.

Hyogo Prefectural Kakogawa Medical Center, Department of Diabetes and Endocrinology
Kakogawa, Japan
TK

Taiyo Kasamatsu, MD.

Hyogo Prefectural Kakogawa Medical Center, Department of Diabetes and Endocrinology
Kakogawa, Japan
NS

Naoya Sakata, MD.

Hyogo Prefectural Kakogawa Medical Center, Department of Diabetes and Endocrinology
Kakogawa, Japan
AM

Atsunori Maeda, MD.

Hyogo Prefectural Kakogawa Medical Center, Department of Diabetes and Endocrinology
Kakogawa, Japan
II

Ikuhiro Ishida, MD.

Hyogo Prefectural Kakogawa Medical Center, Department of Diabetes and Endocrinology
Kakogawa, Japan
YS

Yutaka Shirakawa, MD.

Hyogo Prefectural Kakogawa Medical Center, Department of Gastroenterology
Kakogawa, Japan
AA

Atsushi Arai, MD.

Hyogo Prefectural Kakogawa Medical Center, Department of Neurosurgery
Kakogawa, Japan
YT

Yoshikazu Tamori, MD., PhD

Hyogo Prefectural Kakogawa Medical Center, Department of Diabetes and Endocrinology
Kakogawa, Japan

Disclosure(s):

YASUNORI FUJITA, MD., PhD: No financial relationships to disclose

［Introduction］IgG4-related disease (IgG4-RD) is a multiorgan, relapsing, fibro-inflammatory, immune-mediated disorder with infiltration of IgG4-positive plasma cells. Pituitary gland involvement is rare in IgG4-RD, reported in up to 8% of cases. Here, we report the extremely rare case of IgG4-related hypophysitis, concomitant with relapsed IgG4-related autoimmune pancreatitis (AIP) and pachymeningitis.［Case Presentation］A 74-year-old male with type 1 diabetes mellitus complained of headaches and epigastric discomfort 3 months before. He had a medical history of IgG4-related retroperitoneal fibrosis and IgG4-related AIP metachronously. IgG4-positive plasma cells were identified in the histopathology of the retroperitoneal fibrosis, and prednisolone (PSL) was initiated for each lesion. The administration of PSL has improved the enlargement of the pancreas. After PSL was tapered and maintained at 5 mg/day for approximately 6 years, then PSL were discontinued. On a CT scan, diffuse re-enlargement of the pancreas was identified, suggesting the relapse of IgG4-related AIP. Hematological examination shows elevated serum IgG4 concentrations (410 mg/dL; above 135 mg/dL). And on MRI, diffuse enlargement of the pituitary gland, thickened pituitary stalk, loss of high signal intensity in the posterior pituitary gland on T1-weighted MRI, and thickening of the dura mater were observed. GHRP-2/LHRH/TRH/CRH tests demonstrated the impaired anterior pituitary hormone secretions(GH, LH, FSH), and an excessive ACTH response, suggesting a hypothalamic-pituitary axis disorder. In addition, hypotonic urine (236 mOsm/kg), polyuria, and the improvement of nocturia following DDAVP administration suggested the concomitance of central diabetes insipidus. We recommended a biopsy from the intracranial lesion, but consent was not obtained. Based on these findings, we diagnosed with relapsed IgG4-related AIP, concomitant with IgG4-related hypophysitis and pachymeningitis. PSL 0.6 mg/kg/day was initiated, and all symptoms, including the enlargement of pancreas and pituitary gland, and the thickening of dura mater, were rapidly improved. These findings were consistent with IgG4-RD. [Discussion] Maintenance therapy with PSL 5 mg/day for 3 years is proposed for IgG4-related AIP. Although the proposed regimen was applied to the patient, IgG4-AIP relapsed. Furthermore, the recurrence of IgG4-related AIP was accompanied by pituitary gland and dural lesions. While IgG4-RD often recurs, careful long-term follow-up is crucial.

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