Lymphocytic hypophysitis (LH) is a primary autoimmune inflammatory disease affecting the pituitary gland and infundibulum. Infiltration of B cells and T cells, along with mass effect within the sella turcica, leads to dysregulation of pituitary hormone secretion.
Based on the affected site, it is classified into the following three types.
The annual incidence is approximately 1 in 7 to 9 million people, accounting for about 0.4% of pituitary surgery cases4). It is more common in women, with a female-to-male ratio of 2–4:1, although a ratio of 8.5:1 has been reported in biopsy-confirmed cases1). The mean age at diagnosis is 34.5 years in women and 44.7 years in men1). There is a peak incidence from the third trimester of pregnancy to a few weeks postpartum, but it can also occur in non-pregnant women, postmenopausal women, men, and children.
In a meta-analysis of 492 cases, 58% presented with headache and visual disturbances, 44% with hypopituitarism (most commonly ACTH deficiency), 31% with polyuria and polydipsia, and 18% with hyperprolactinemia2).
The association with pregnancy is strong but not a prerequisite. Cases have been reported in non-pregnant women1), postmenopausal elderly women3, 5), men, and children6, 7, 8). A family or personal history of autoimmune disease is a risk factor.
Symptoms of LH arise from two mechanisms: dysregulation of hormone secretion and mass effect.
Visual impairment occurs in 15–52% of patients with primary hypophysitis, most frequently in LAH.
Afferent Pathway Disorder
Chiasmal syndrome: 15%. Bitemporal hemianopia is typical.
Decreased visual acuity: 16%. Due to optic nerve compression.
Visual field defect: 34%. Presents with various patterns such as optic nerve type, junctional type, and optic tract type.
Efferent pathway disorders
Ocular motor palsy: 7%. Diplopia due to compression of cranial nerves III, IV, and VI in the cavernous sinus.
Anisocoria: Caused by Horner syndrome or oculomotor nerve palsy.
Ptosis: A sign of oculomotor nerve (CN III) palsy.
Watanabe et al. (2024) reported a case of recurrent LH presenting with right eye pain and oculomotor nerve palsy (ptosis, limited adduction, limited vertical movement, and loss of light reflex)3). MRI/MRA showed a pituitary mass extending into the cavernous sinus with severe stenosis of the right internal carotid artery (ICA). Intravenous methylprednisolone (IVMP) dramatically improved eye pain and oculomotor nerve palsy, but ICA stenosis persisted due to irreversible fibrosis. This was the first report of combined oculomotor nerve palsy and ICA stenosis.
Visual impairment occurs in 15–52% of patients with primary hypophysitis. A meta-analysis of 492 cases reported headache and visual impairment in 58%2). It is more frequent in LAH (adenohypophysitis) than in LINH or panhypophysitis. Visual acuity loss is reported in 16% and visual field defects in 34%.
The etiology of LH is not fully understood, but an autoimmune mechanism is widely supported.
Secondary hypophysitis develops in the context of underlying diseases such as hemochromatosis, tuberculosis, syphilis, and sarcoidosis. Drug-induced hypophysitis due to immune checkpoint inhibitors has also been increasing in recent years.
The definitive diagnosis of LH is made by pituitary biopsy obtained via the trans-sphenoidal approach. Histologically, infiltration of lymphocytes, plasma cells, and macrophages, and occasionally germinal center formation, are observed1). Leukocyte common antigen (LCA) positivity is confirmed1). If biopsy is not performed, the diagnosis is based on exclusion.
Comprehensive evaluation of pituitary hormones is essential.
MRI is the primary imaging modality.
The scoring system developed by Gutenberg et al. is useful for differentiating pituitary adenoma from LH 2). A score ≤0 suggests LH.
| Item | Suggests LH | Suggests adenoma |
|---|---|---|
| Age/Sex | Young female | Elderly |
| Association with pregnancy | Present | Absent |
| Pituitary morphology | Diffuse enlargement | Focal mass |
In recent years, it has attracted attention as a serum biomarker for lymphocytic infundibuloneurohypophysitis (LINH).
Non-invasive diagnosis is becoming possible through comprehensive evaluation of clinical and imaging findings using the Gutenberg scoring system2) and measurement of anti-rabphilin-3A antibodies (sensitivity 100% and specificity 97.4% for LINH)6). However, biopsy is essential when neoplastic diseases need to be excluded.
In a meta-analysis of 17 studies, 36% received steroid therapy and 34% underwent surgery 2). Non-surgical management is the recommended first-line treatment.
Transsphenoidal surgery (TSS) is more likely to cause secondary pituitary dysfunction compared to conservative therapy, and its effect on improving disease regression is limited. Therefore, it is indicated only in the following cases.
TSS is useful for both decompression of the sella turcica and histological diagnosis, but significant improvement in endocrine dysfunction is not expected.
IVMP may be effective for acute visual impairment. In a report by Watanabe et al., IVMP 1000 mg/day for 3 days dramatically improved oculomotor nerve palsy and eye pain 3). On the other hand, optic nerve damage due to long-term compression or fibrosis can become irreversible, so early treatment intervention is important.
The pathophysiology of LH progresses as follows.
The following non-specific antibodies against pituitary antigens have been reported.
Noninvasive evaluation of pituitary inflammation using FDG-PET has successfully identified IgG4-related disease and is being applied to elucidate the clinical significance of HLA markers (such as DQ8). DQ8 is significantly elevated in patients with primary LH, and its future application in screening is expected.
Watanabe et al. (2024) reported a case in which an inflammatory mass of LH extended into the cavernous sinus, causing severe stenosis of the right ICA3). The mass shrank with IVMP, but the ICA stenosis persisted due to irreversible fibrosis. There have been two case reports of cerebral infarction due to ICA stenosis caused by LH, one of which required bypass surgery for bilateral ICA occlusion. It is suggested that chronic inflammation leads to fibrosis and stenosis of the vessel wall.
Anti-rabphilin-3A (RPH3A) antibody is attracting attention as a highly sensitive and specific serum biomarker for LINH.
| Target | Sensitivity | Specificity |
|---|---|---|
| LINH | 100% | 97.4% |
| LPH | 80% | 97.4% |
Yamamoto et al. (2025) confirmed anti-rabphilin-3A antibody positivity in a 4-year-old boy and diagnosed LINH without biopsy 6). After conservative treatment with desmopressin alone, the pituitary stalk thickening on MRI resolved after 5 months. This was the youngest case of anti-rabphilin-3A antibody positivity.
Shoji et al. (2025) detected anti-rabphilin-3A antibody positivity in an 8-year-old boy only 3 months after the onset of central diabetes insipidus 7). This suggested its potential as an early diagnostic marker. Steroids were not administered, and the pituitary stalk enlargement on MRI decreased after 9 months.
Kume et al. (2021) confirmed anti-rabphilin-3A antibody positivity in a 10-year-old boy 9 years after the onset of central diabetes insipidus, and retrospectively diagnosed LINH 8). He was treated with prednisolone at 1 mg/kg/day, tapered by 0.25 mg/kg every 2 weeks. Cumulative reports of pediatric LH in Japan include 35 cases, with a mean age of 7.2 years, 57.5% male, and 76% GH deficiency.
Joshi et al. (2022) reported an 18-year-old female who developed acute frontal throbbing headache 3 weeks after COVID-19 infection 4). MRI showed diffuse thickening (4 mm) and homogeneous enhancement of the infundibulum, but all hormonal axes were normal. Headache markedly improved with methylprednisolone 250 mg IV every 6 hours for 3 days, and the lesion completely resolved on MRI on day 5. As the first report of LH after COVID-19, a post-infection immune-mediated mechanism is suggested.
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Shen K, Cadang C, Phillips D, Babu V. Unique case of lymphocytic hypophysitis with normal pituitary hormone serology mimicking a non-functioning pituitary adenoma. BMC Endocr Disord. 2024;24(1):20.
Watanabe Y, Maruoka H, Yokote H, Uchihara T, Toru S. Recurrent lymphocytic hypophysitis presenting as internal carotid artery stenosis and oculomotor nerve palsy. Intern Med. 2024;63(11):1623-1625.
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Yamamoto A, Komatsu N, Iwata N, Fujisawa H, Suzuki A, Sugimura Y. A 4-year-old boy positive for anti-rabphilin-3A antibody and diagnosed with lymphocytic infundibuloneurohypophysitis. JCEM Case Rep. 2025;3(1):luae214.
Shoji Y, Naruse Y, Iwata N, Fujisawa H, Suzuki A, Sugimura Y, Mori M, Hiramoto R. Diagnosis of lymphocytic infundibuloneurohypophysitis after positive anti-rabphilin-3A antibody test in an 8-year-old boy with early-onset central diabetes insipidus. J Clin Res Pediatr Endocrinol. 2025;17(3):332-336.
Kume Y, Sakuma H, Sekine H, Sumikoshi M, Sugimura Y, Hosoya M. Lymphocytic infundibuloneurohypophysitis with positive anti-rabphilin-3A antibodies nine years post-onset of central diabetes insipidus. Clin Pediatr Endocrinol. 2021;30(1):65-69.
