Lymphocytic infundibulo neurohypophysitis [Neurosurgery Wiki]

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====== Lymphocytic infundibulo neurohypophysitis ======

[[Lymphocytic adenohypohysitis]] and lymphocytic infundibulo neurohypophysitis are rare [[autoimmune]] mediated diseases of the anterior and [[posterior pituitary]], respectively. 

Lymphocytic infundibulo-neurohypophysitis (LINH) was first reported by Saito et al. and Imura et al. as a cause of idiopathic [[central diabetes insipidus]]
((Abe T. Lymphocytic infundibulo-neurohypophysitis and
infundibulo-panhypophysitis regarded as lymphocytic hypophysitis variant. Brain
Tumor Pathol. 2008;25(2):59-66. doi: 10.1007/s10014-008-0234-8. Epub 2008 Nov 6. 
Review. PubMed PMID: 18987830.
)).

===== Etiology =====

Lymphocytic infundibulo neurohypophysitis is an uncommon [[inflammatory disease]] postulated to be [[autoimmune]] in origin. 

===== Pathophysiology =====

Still unknown
((Abe T. Lymphocytic infundibulo-neurohypophysitis and
infundibulo-panhypophysitis regarded as lymphocytic hypophysitis variant. Brain
Tumor Pathol. 2008;25(2):59-66. doi: 10.1007/s10014-008-0234-8. Epub 2008 Nov 6. 
Review. PubMed PMID: 18987830.
)).

Yasuda et al., reported that rabphilin-3A ([[RPH3A]])an autoantigen and that anti-rabphilin-3A antibodies constitute a possible diagnostic marker for LINH. However, the involvement of rabphilin-3A in the pathogenesis of LINH remains to be elucidated. This study was undertaken to explore the role of rabphilin-3A in lymphocytic neurohypophysitis and to investigate the mechanism. They found that immunization of mice with rabphilin-3A led to neurohypophysitis. Lymphocytic infiltration was observed in the neurohypophysis and supraoptic nucleus 1 month after the first immunization. Mice immunized with rabphilin-3A showed an increase in the volume of urine that was hypotonic as compared with control mice. Administration of a cocktail of monoclonal anti-rabphilin-3A antibodies did not induce neurohypophysitis. However, abatacept, which is a chimeric protein that suppresses T-cell activation, decreased the number of T cells specific for rabphilin-3A in peripheral blood mononuclear cells (PBMCs). It ameliorated lymphocytic infiltration of CD3+ T cells in the neurohypophysis of mice that had been immunized with rabphilin-3A. Additionally, there was a linear association between the number of T cells specific for rabphilin-3A in PBMCs and the number of CD3+ T cells infiltrating the neurohypophysis. In conclusion, we suggest that rabphilin-3A is a pathogenic antigen, and that T cells specific for rabphilin-3A are involved in the pathogenesis of neurohypophysitis in mice
((Yasuda Y, Iwama S, Kiyota A, Izumida H, Nakashima K, Iwata N, Ito Y, Morishita
Y, Goto M, Suga H, Banno R, Enomoto A, Takahashi M, Arima H, Sugimura Y. Critical
role of rabphilin-3A in the pathophysiology of experimental lymphocytic
neurohypophysitis. J Pathol. 2018 Apr;244(4):469-478. doi: 10.1002/path.5046.
Epub 2018 Mar 9. PubMed PMID: 29377134.
)).

===== Clinical features =====

Because of the location of inflammation, it selectively affects the posterior lobe of the [[pituitary]] ([[neurohypophysis]]) and [[pituitary stalk]] ([[infundibulum]]). The most common presentation is [[central diabetes insipidus]]. 

===== Diagnosis =====

In the majority of patients, Hypophysitis can be reliably identified by characteristic clinical signs and symptoms, obviating histological confirmation. The diagnostic approach should be standardized
((Honegger J, Schlaffer S, Menzel C, Droste M, Werner S, Elbelt U, Strasburger
C, Störmann S, Küppers A, Streetz-van der Werf C, Deutschbein T, Stieg M,
Rotermund R, Milian M, Petersenn S; Pituitary Working Group of the German Society
of Endocrinology. Diagnosis of Primary Hypophysitis in Germany. J Clin Endocrinol
Metab. 2015 Oct;100(10):3841-9. doi: 10.1210/jc.2015-2152. Epub 2015 Aug 11.
PubMed PMID: 26262437.
)).

Although the definitive diagnosis is established histologically by a pituitary biopsy, radiological imaging can be valuable in diagnosing this condition
((Johnston PC, Chew LS, Hamrahian AH, Kennedy L. Lymphocytic
infundibulo-neurohypophysitis: a clinical overview. Endocrine. 2015
Dec;50(3):531-6. doi: 10.1007/s12020-015-0707-6. Epub 2015 Jul 29. Review. PubMed
PMID: 26219407.
)).
----
Magnetic resonance (MR) imaging with a contrast medium demonstrates thickening of the [[pituitary stalk]], enlargement of the [[neurohypophysis]], or both with homogeneous enhancement. Histological examination reveals a posterior pituitary that is heavily infiltrated by [[lymphocyte]]s with occasional [[plasma cell]]s and other [[inflammatory cell]]s. In early reports of the disorder, the lesion seemed to be limited to the neurohypophysis, but Abe
((Abe T. Lymphocytic infundibulo-neurohypophysitis and
infundibulo-panhypophysitis regarded as lymphocytic hypophysitis variant. Brain
Tumor Pathol. 2008;25(2):59-66. doi: 10.1007/s10014-008-0234-8. Epub 2008 Nov 6. 
Review. PubMed PMID: 18987830.
)),
showed cases with a combination of [[hypopituitarism]] and [[diabetes insipidus]]. Some of them showed partial hypopituitarism. The so-called lymphocytic infundibulo-panhypophysitis (LIPH) is now regarded as a [[lymphocytic hypophysitis]] variant. Lymphocytic infundibulo-neurohypophysitis (LINH) and LIPH are essentially self-limited. 
===== Treatment =====

In typical cases, conservative care with [[steroid]]s and [[hormone]] replacement is recommended. Surgical intervention should be avoided because the natural course of the disorder may be self-limited
((Abe T. Lymphocytic infundibulo-neurohypophysitis and
infundibulo-panhypophysitis regarded as lymphocytic hypophysitis variant. Brain
Tumor Pathol. 2008;25(2):59-66. doi: 10.1007/s10014-008-0234-8. Epub 2008 Nov 6. 
Review. PubMed PMID: 18987830.
)),

===== Case report =====

Shibue et al. describe a case showing the serial progression of lymphocytic infundibuloneurohypophysitis (LINH) to panhypopituitarism with extrapituitary inflammatory invasion in a short period, and responding favorably to high-dose glucocorticoid treatment.
PATIENT CONCERNS:
Polyuria, General fatigue and Nausea/Vomiting.
DIAGNOSES:
Central diabetes insipidus (CDI), Lymphocytic infundibuloneurohypophysitis (LINH).
INTERVENTIONS:
Desmopressin acetate, High-dose glucocorticoid (GC) treatment.
OUTCOMES:
He was prescribed desmopressin acetate and subsequently discharged. A month later, he revisited our hospital with general fatigue and nausea/vomiting. A screening test disclosed hypopituitarism with adrenal insufficiency. MRI revealed expanded contrast enhancement to the peripheral extrapituitary lesion. He received high-dose GC treatment and the affected lesion exhibited marked improvement on MRI, along with the recovery of the anterior pituitary function.
LESSONS:
This case demonstrates the potential for classical LINH to develop into panhypopituitarsim. We consider this is the first documentation of approaching the cause of atypical LINH with progressive clinical course from the pathological viewpoint
((Shibue K, Fujii T, Goto H, Yamashita Y, Sugimura Y, Tanji M, Yasoda A, Inagaki
N. Rapid exacerbation of lymphocytic infundibuloneurohypophysitis. Medicine
(Baltimore). 2017 Mar;96(9):e6034. doi: 10.1097/MD.0000000000006034. PubMed PMID:
28248860; PubMed Central PMCID: PMC5340433.
)).