IgG4-related disease–like fibrosis as an indicator of IgG4

IgG4-related disease–like fibrosis as an indicator of IgG4

Annals of Diagnostic Pathology 17 (2013) 416–420
Contents lists available at ScienceDirect
Annals of Diagnostic Pathology
IgG4-related disease–like fibrosis as an indicator of IgG4-related lymphadenopathy☆
Takeshi Uehara MD, PhD a,⁎, Junya Masumoto MD, PhD b, Akihiko Yoshizawa MD, PhD a,
Yukihiro Kobayashi MT, PhD a, Hideaki Hamano MD, PhD c, Shigeyuki Kawa MD, PhD d, Keiko Oki MT e,
Nao Oikawa MT f, Takayuki Honda MD, PhD a, Hiroyoshi Ota MD, PhD a, g
a
Department of Laboratory Medicine, Shinshu University School of Medicine, Matsumoto 390-8621, Japan
Department of Pathogenomics, Ehime University Graduate School of Medicine, Toon, Japan
Second Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
d
Center for Health, Safety and Environmental Management, Shinshu University, Matsumoto, Japan
e
Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan
f
Department of Laboratory Medicine, Nagano Chuo Hospital, Nagano, Japan
g
Department of Biomedical Laboratory Medicine, Shinshu University School of Medicine, Matsumoto, Japan
b
c
a r t i c l e
i n f o
Keywords:
IgG4-related diseases
IgG4-related lymphadenopathy
IgG4-related lymphadenopathy with fibrosis
IgG4-positive plasma cell/IgG-positive plasma
cell ratio
a b s t r a c t
The significance of IgG4-related diseases including IgG4-related lymphadenopathy has recently been
recognized worldwide. Inflammatory pseudotumors in lymph nodes, as well as in other organs, are also
recognized as IgG4-related diseases. Only a few case reports have described IgG4-related lymphadenopathy
with fibrosis (IgG4-fibrosing lymphadenopathy), and IgG4-fibrosing lymphadenopathy has not been
compared clinicopathologically with non–IgG4-related lymphadenopathy with fibrosis. We have evaluated
the pathologic features in 13 patients with IgG4-fibrosing lymphadenopathy, including IgG4 and IgG
expression in lymph nodes, and compared these features with those of patients with non–IgG4-related
lymphadenopathy with fibrosis with reactive inguinal lymphadenopathy and focal fibrosis and lymph nodes
at least 10 mm in diameter. IgG4-fibrosing lymphadenopathy was characterized by lymphoplasmacytic and
eosinophilic infiltration, many IgG4-positive plasma cells in fibrotic areas, and high serum IgG4
concentrations. The IgG4-positive/IgG-positive plasma cell ratio was significantly higher in the IgG4-fibrosing
lymphadenopathy than in the non–IgG4-fibrosing lymphadenopathy group. The presence of even minor
fibrosis with characteristics of IgG4-related disease such as IgG4-fibrosing lymphadenopathy may facilitate
the diagnosis of IgG4-related lymphadenopathy.
© 2013 Elsevier Inc. All rights reserved.
1. Introduction
IgG4-related disease has been recently recognized as a systemic
syndrome, ever since elevated serum IgG4 concentrations were
observed in patients with autoimmune pancreatitis (AIP) [1]. IgG4related disease is a unique inflammatory condition characterized by
high serum IgG4 concentrations and mass-forming lesions in the
affected organs [1]. IgG4-related diseases have been reported in
organs other than those in the pancreaticobiliary system [2-13]. Their
common histologic features include diffuse lymphoplasmacytic
inflammation with numerous IgG4-bearing plasma cells, storiform
fibrosis, obliterative phlebitis, and eosinophil infiltration [14]. Steroid
Abbreviations: IgG4-lymphadenopathy, IgG4-related lymphadenopathy; IP, inflammatory pseudotumor; IgG4-fibrosing lymphadenopathy, IgG4-related lymphadenopathy with
fibrosis; Non–IgG4-fibrosing lymphadenopathy, non–IgG4-related lymphadenopathy with
fibrosis; IgG4/IgG ratio, IgG4-positive plasma cell/IgG-positive plasma cell ratio.
☆ Conflict of interest: None.
⁎ Corresponding author. Tel.: +81 263 37 2805; fax: +81 263 34 5316.
E-mail address: [email protected] (T. Uehara).
1092-9134/$ – see front matter © 2013 Elsevier Inc. All rights reserved.
http://dx.doi.org/10.1016/j.anndiagpath.2013.04.010
therapy has been found to alleviate the symptoms in most patients
with IgG4-related disease [15,16].
IgG4-related disease has also been reported to occur in lymph
nodes [17-19]. This condition, called IgG4-related lymphadenopathy
(IgG4-lymphadenopathy), has been classified into 5 types: Castleman disease–like morphology (type I), reactive follicular hyperplasia (type II), interfollicular plasmacytosis and immunoblastosis
(type III), progressive transformation of germinal center–like
disease (type IV), and inflammatory pseudotumor (IP)–like disease
(type V) [18]. Type V IgG4-lymphadenopathy is accompanied by
fibrosis and resembles IgG4-related diseases observed in other
organs, as well as several IPs. In addition, some IPs in lymph
nodes, as well as in other organs [13,20], are recognized as IgG4related diseases [18], and a case report described a patient with
IgG4-related lymphadenopathy with fibrosis (IgG4-fibrosing
lymphadenopathy) [21], similar to IP. To determine the clinicopathologic characteristics of IgG4-fibrosing lymphadenopathy, we
collected specimens from 13 patients with this condition and
compared their pathologic features with those of patients with
non–IgG4-related lymphadenopathy with fibrosis (non–IgG4-fibrosing lymphadenopathy).
T. Uehara et al. / Annals of Diagnostic Pathology 17 (2013) 416–420
2. Methods
2.1. Patients and materials
Between 1996 and 2010, we identified lymphadenopathy (diameter N10 mm) in histologic specimens of 18 patients with IgG4-related
disease, of these, specimens from 13 patients had fibrotic areas (at
least 5%) in the lymph nodes. We considered these 13 patients as
having IgG4-fibrosing lymphadenopathy. We analyzed the clinical
and histopathologic characteristics of these 13 patients with IgG4fibrosing lymphadenopathy (Table 1) as well as 16 patients with non–
IgG4-fibrosing lymphadenopathy treated at Shinshu University
Hospital, Matsumoto, Japan. Of the 13 patients with IgG4-fibrosing
lymphadenopathy, 7 had type 1 AIP (AIP-1), recently defined as an
IgG4-related disease [22]; 5 had IgG4-related sialadenitis; 4 had IgG4related lung disease showing an interstitial pneumonia pattern; and 2
had retroperitoneal fibrosis consistent with IgG4-related disease. One
patient had IgG4-related periaortitis, 1 had IgG4-related sclerosing
cholangitis, 1 had IgG4-related prostatitis, and 1 had IgG4-related
tubulointerstitial nephritis. All 13 patients with IgG4-fibrosing
lymphadenopathy had high serum IgG4 concentrations (N135 mg/
dL), and all, except for patient 8, were histologically diagnosed as
having IgG4-related diseases by evaluating specimens obtained from
at least 1 organ other than lymph nodes. Histologically, all specimens
showed partial or diffuse fibrosis.
Specimens obtained from 10 patients with IgG4-fibrosing lymphadenopathy (patients 2, 4, 6-13) included biopsy specimens, whereas
specimens obtained from the other 3 patients (patients 1, 3, and 5)
included surgical specimens obtained during pancreatic surgery from
lymph nodes around the pancreas. Of the 10 IgG4-fibrosing
lymphadenopathy biopsy specimens, 7 were from the cervical region
and 1 each from the inguinal axillary and mediastinal regions.
The control group consisted of 16 patients with non–IgG4fibrosing lymphadenopathy who had focal fibrosis (≥5%) and inguinal
lymph nodes of 10 mm or greater in size.
2.2. Histopathology and immunohistochemistry
All specimens were fixed in 20% formaldehyde and embedded in
paraffin. Four 4-μm-thick serial sections were cut from these blocks
and stained with hematoxylin-eosin (HE). Sections were also reacted
Table 1
Clinical features of patients with IgG4-fibrosing lymphadenopathy
LN region
Patient Age Sex Serum
no.
(y)
IgG4
(mg/dL)a
Systemic LN AIP-1
swelling
1
2
3
4
5
6
7
8
65
61
83
69
56
63
67
68
M
M
M
M
M
M
F
M
663
500
201
1705
265
2855
1110
2470
Pancreatic
Inguinal
Pancreatic
Cervical
Pancreatic
Cervical
Axillary
Cervical
NA
NA
NA
NA
NA
None
None
None
Present
Present
Present
Present
Present
Present
Present
Absent
9
10
11
60
59
54
F
F
F
1800
364
931
Cervical
None
Mediastinal Yes
Cervical
Yes
Absent
Absent
Absent
12
62
M
323
Cervical
Yes
Absent
13
72
M
2760
Cervical
Yes
Absent
417
with antibodies to IgG (1:5000; Dako, Glostrup, Denmark) and IgG4
(1:50; The Binding Site, Birmingham, UK). The numbers of IgG4- and
IgG-positive cells were estimated by counting cells in a number of
sections from the same sample at the areas with the highest density
of positive cells. In samples from patients with IgG4-fibrosing
lymphadenopathy, the numbers of IgG4- and IgG-positive cells
were estimated in fibrotic areas with the highest density of positive
cells. In samples from patients with non–IgG4-fibrosing lymphadenopathy, the numbers of cells were also estimated in fibrotic areas.
The cells in the highest-density area in each sample were counted
under high-power fields (HPF; 10× eyepiece and 40× objective). The
density of IgG4-positive cells and the IgG4-positive/IgG-positive
plasma cell ratio (IgG4/IgG ratio) were compared in samples from
IgG4-fibrosing lymphadenopathy and patients with non–IgG4-fibrosing lymphadenopathy. The levels of inflammation in the fibrotic
areas of the lymph node were scored as mild (10-30 inflammatory
cells/HPF), moderate (30-100 cells/HPF), or severe (N100 cells/HPF)
[23], and the levels of eosinophil infiltration into fibrotic areas of the
lymph nodes were scored as 1 (none-mild; 0-5/HPF), 2 (moderate;
6-10/HPF), or 3 (severe; N10/HPF) [12]. Inflammation was assessed
and graded independently by 2 pathologists (T.U. and H.O.). Other
histologic features examined included capsular fibrosis, obliterative
phlebitis, extracapsular lymph node extension of inflammatory cells,
and fibrosis.
The data are expressed as the median (25th-75th percentile) and
compared in the 2 groups using the Mann-Whitney U test. A P value
less than .05 was considered statistically significant.
This study was approved by the ethics committee of Shinshu
University, Japan.
3. Results
3.1. Clinical findings
Of the 13 patients with IgG-LF, 4 had systemic lymphadenopathy, 4
had local lymphadenopathy, and 5 had unidentified clinical conditions (Table 1).
3.2. Histologic findings
The histologic characteristics of the 13 patients with IgG4fibrosing lymphadenopathy are summarized in Table 2. Mean lymph
node size was 17.08 ± 8.92 mm. In IgG4-fibrosing lymphadenopathy,
focal fibrosis (Fig. 1A, B) and diffuse fibrosis (Fig. 1D, E) were observed
IgG4-related
disease
Table 2
Histologic findings of samples from patients with IgG4-fibrosing lymphadenopathy
RF, IgG4-S
IgG4-SC
IgG4-P
IgG4-S,
IgG4-PA
IgG4-S
IgG4-LD
IgG4-S,
IgG4-LD
RF, IgG4-LD,
IgG4-TN
IgG4-S,
IgG4-LD
F, female; IgG4-LD, IgG4-related lung disease; IgG4-P, IgG4-related prostatitis; IgG4-PA,
IgG4-related periaortitis; IgG4-S, IgG4-related sialadenitis; IgG4-SC, IgG4-related
sclerosing cholangitis; IgG4-TN, IgG4-related tubulointerstitial nephritis; LN, lymph
node; M, male; NA, not available; RF, retroperitoneal fibrosis.
a
Normal value: IgG4, less than 70 mg/dL (cutoff value, 135 mg/dL).
Test,
P value
Features
IgG4-fibrosing
lymphadenopathy
(n = 13)
Non–IgG4-fibrosing
lymphadenopathy
(n = 16)
Lymph node size (mm)
Fibrosis (focal/diffuse)
Lymphoplasmacytic
infiltration,
mild/moderate/severe
Eosinophil infiltration,
score 1 (none-mild)/
score 2 (moderate)/
score 3 (severe)
Obliterative phlebitis,
present/absent
Extracapsular fibrosis with
lymphoplasmacytic
infiltration,
present/absent
Thickening of capsule,
present/absent
17.08 ± 8.92
11/2
4/3/6
14.81 ± 4.15
16/0
7/7/2
1/6/6
16/0/0
2/11
0/16
.1921
8/5
2/14
.0161
13/0
9/7
.0084
.1921
.5686
.1672
b.0001
418
T. Uehara et al. / Annals of Diagnostic Pathology 17 (2013) 416–420
Fig. 1. Lymph node specimen from a patient with IgG4-fibrosing lymphadenopathy. (A) The specimen showed diffuse fibrosis, inflammatory cell infiltration with diffuse distribution,
and a disarrayed fibrotic lymph node structure. (B) Various degrees of lymphoplasmacytic and scattered eosinophil infiltration were detected, along with fibrosis and hyalinosis. (C)
Infiltration of IgG4-positive plasma cells was also noted. (D) A specimen showing focal fibrosis and inflammatory cell infiltration with diffuse distribution within the focal disruption
of the lymph node architecture. (E) Specimens showing various degrees of lymphoplasmacytic and scattered eosinophil infiltration, along with fibrosis and hyalinosis. (F) Infiltration
of IgG4-positive plasma cells. (A, B, D, E) HE staining, original magnification ×25 (A, D) and ×100 (B, E). (C, F) Immunostaining for IgG4, original magnification, ×100.
in 11 (patients 1-7,9,10,11, and 13) and 2 (patients 8 and 12) patients,
respectively. Both IgG4-fibrosing lymphadenopathy and non–IgG4fibrosing lymphadenopathy showed various degrees of inflammation.
There was no statistically significant difference between the 2 groups
with respect to fibrosis, lymphoplasmacytic infiltration, and obliterative phlebitis. Eosinophil infiltration was present in all patients in the
IgG4-fibrosing lymphadenopathy group and was significantly higher
and more frequent than that in the non–IgG4-lymphadenopathy
group (P b .0001). In 8 patients(2, 5-10, and 12) with IgG4-fibrosing
lymphadenopathy, we observed extracapsular fibrosis, with lymphoplasmacytic infiltration around the adipose tissue surrounding the
lymph node (Fig. 2A). Extracapsular fibrosis in the IgG4-fibrosing
lymphadenopathy group was significantly more frequent than that in
the non–IgG4-fibrosing lymphadenopathy group (P = .0161).
Samples from all 13 patients with IgG4-fibrosing lymphadenopathy
showed thickening of the capsule with lymphoplasmacytic inflammation (Fig. 2B). Thickening of the capsule was significantly more
frequent in the in IgG4-fibrosing lymphadenopathy than in the non–
IgG4-fibrosing lymphadenopathy group (P = .0084).
All 11 patients with IgG4-fibrosing lymphadenopathy with focal
fibrosis had other IgG4-lymphadenopathy subtypes [18] in their
lymph nodes, including 7 (patients 1, 2, 6, 7, 9, 10, and 13) with type
III, 3 (3, 5, and 11) with type II, and 1 (4) with a mixture of types I, II,
and IV.
3.3. Immunohistochemical and other test findings
Many IgG4-positive plasma cells were detected in fibrotic areas of
samples taken from the IgG4-fibrosing lymphadenopathy group
(Fig. 1C, F). Extracapsular and capsular fibrotic areas also contained
IgG4-positive plasma cells. In contrast, the number of IgG4-positive
plasma cells in the non–IgG4-fibrosing lymphadenopathy group
was negligible.
When we assessed IgG4-positive plasma cell infiltration into
nonfibrotic areas in the IgG4-fibrosing lymphadenopathy specimens,
we found that specimens from all 13 patients showed interfollicular
distribution of many IgG4-positive plasma cells. In 1 patient (patient
4), IgG4-positive plasma cells formed an intragerminal center in an
area with Castleman disease–like morphology.
The median IgG4/IgG ratio was significantly higher in the fibrotic
areas of samples from the IgG4-fibrosing lymphadenopathy than from
T. Uehara et al. / Annals of Diagnostic Pathology 17 (2013) 416–420
419
Fig. 2. Lymph node specimen from a patient with IgG4-fibrosing lymphadenopathy. (A) Extension of inflammatory cell infiltration and fibrosis to extracapsular lymph nodes. (B)
Capsule showing thickening with lymphoplasmacytic inflammation. (A, B) HE staining, original magnification ×25.
the non–IgG4-fibrosing lymphadenopathy group (0.69 [range, 0.490.75] vs 0.00 [range, 0.00-0.02], P b .0001; Fig. 3).
4. Discussion
We have evaluated the histopathologic characteristics of patients
with IgG4-fibrosing lymphadenopathy, all of whom had high serum
IgG4 concentrations. Fibrotic areas of these tissue specimens showed
the infiltration of many lymphoplasmacytic and eosinophilic cells,
accompanied by many IgG4-positive plasma cells. Thickening of the
capsule and extracapsular fibrosis were also observed in patient with
IgG4-fibrosing lymphadenopathy, and immunohistochemical analysis
showed that the IgG4/IgG ratio was higher in the IgG4-fibrosing
lymphadenopathy group than in the non–IgG4-fibrosing lymphadenopathy group. The fibrotic areas in patients with IgG4-fibrosing
lymphadenopathy were similar to those observed in other IgG4related diseases.
Our patients with clinical systemic lymphadenopathy were similar
to described previously report [18]. In a recent study, IgG4-fibrosing
lymphadenopathy was classified as type V IgG4-lymphadenopathy,
showing that diffuse fibrosis and lymph nodes in these patients
showed histologic features similar to those of stage III IP (complete
Fig. 3. IgG4-positive/IgG-positive plasma cell ratios in patients with IgG4-fibrosing
lymphadenopathy and non–IgG4-fibrosing lymphadenopathy. Scores are expressed as
minimum, 25th and 75th (percentiles), and maximum. *P b .0001 vs non–IgG4lymphadenopathy (Mann-Whitney U test).
fibrosis) [18,24]. However, 11 patients in our study showed focal
fibrosis, corresponding to stage II IP (distortion of the connective
tissue framework) [24]. Although similarity of IgG4-fibrosing lymphadenopathy and stage III IP is histopathologically pointed out [18],
IgG4-fibrosing lymphadenopathy may be more similar to stage II IPs.
Because the capsular fibrosis and fibrosis of surrounding tissue in our
patients were consistent with the characteristics of IPs [24], these
findings might be characteristic of IgG4-fibrosing lymphadenopathy.
Eosinophil infiltration was also characteristically in touch with other
IgG4-related diseases [25]. Although only 2 patients with IgG4fibrosing lymphadenopathy had phlebitis, phlebitis might be an
important factor to distinguish IgG4-fibrosing lymphadenopathy and
non–IgG4-fibrosing lymphadenopathy.
The fibrosis observed in the IgG4-fibrosing lymphadenopathy
group was easily distinguished from the fibrosis in inguinal lymph
nodes of the control group using IgG4/IgG ratio, although the levels of
inflammation did not differ significantly in the IgG4-fibrosing
lymphadenopathy and non–IgG4-fibrosing lymphadenopathy groups.
Although the IgG4/IgG ratio in lymph nodes was not compared in
patients with IgG4-fibrosing lymphadenopathy and IP, this ratio in
other organs was important in differentiating IgG4-related disease
from IP [20], suggesting that the IgG4/IgG ratio may distinguish
between IgG4-fibrosing lymphadenopathy and IP in lymph nodes. The
higher IgG4/IgG ratios we observed were in agreement with those in
previous reports of patients with IgG4-lymphadenopathy [17,19].
Those reports, however, did not regard type V IgG4-lymphadenopathy
as IgG4-fibrosing lymphadenopathy, although, in one report, 1 patient
with IgG4-fibrosing lymphadenopathy had an IgG4/IgG ratio of 0.571
[21]. The IgG4/IgG ratio in patients with AIP-1 who present with IgG4related disease is greater than 0.5 [22], suggesting that this ratio may
be appropriate in patients with IgG4-fibrosing lymphadenopathy.
Further investigations are required to accurately clarify the range of
IgG4/IgG ratios in patients with IgG4-lymphadenopathy.
Specimens from patients with IgG4-lymphadenopathy show a
diverse range of histologic characteristics. Most patients with IgG4related diseases show lymphoplasmacytic infiltration, although no
fibrosis is observed in the lymph nodes affected by IgG4-related
diseases. As sources of lymphoid cells, lymph nodes are histologically
heterogeneous, even in the absence of fibrosis. A previous study showed
that IgG4-lymphadenopathy was histologically diverse, although
fibrosis was not evaluated [17]. IgG4-fibrosing lymphadenopathy,
however, is a subtype of IgG4-lymphadenopathy. Lymph nodes affected
by external inflammation may become fibrotic. Extracapsular fibrosis
420
T. Uehara et al. / Annals of Diagnostic Pathology 17 (2013) 416–420
was observed in a specimen obtained from the lymph node proximal to
the pancreas of patient 5, who had been diagnosed as having AIP-1. All
11 patients with IgG4-fibrosing lymphadenopathy with focal fibrosis
had other IgG4-lymphadenopathy subtypes in their lymph nodes, so
these findings suggest that IgG4-lymphadenopathy may be heterogeneous within each lymph node.
In summary, we have described the morphologic characteristics of
IgG4-fibrosing lymphadenopathy. Because IgG4-related diseases
including IgG4-lymphadenopathy have only been recognized recently, their clinicopathologic features require further clarification.
Detection of focal IgG4-related disease–like fibrosis and stratification
of IgG4/IgG ratios may help identify IgG4-fibrosing lymphadenopathy
as a subset of IgG4-lymphadenopathy.
Acknowledgments
We are grateful to Masanobu Momose, Yasuyo Shimojo, Mieko
Horikawa, Yayoi Uehara, Megumu Kubota, and Masaomi Takahashi at
Shinshu University Hospital for their excellent technical assistance.
References
[1] Hamano H, Kawa S, Horiuchi A, et al. High serum IgG4 concentrations in patients
with sclerosing pancreatitis. N Engl J Med 2001;344:732–8.
[2] Hamano H, Kawa S, Ochi Y, et al. Hydronephrosis associated with retroperitoneal
fibrosis and sclerosing pancreatitis. Lancet 2002;359:1403–4.
[3] Kamisawa T, Funata N, Hayashi Y, et al. A new clinicopathological entity of IgG4related autoimmune disease. J Gastroenterol 2003;38:982–4.
[4] Notohara K, Burgart LJ, Yadav D, et al. Idiopathic chronic pancreatitis with
periductal lymphoplasmacytic infiltration: clinicopathologic features of 35 cases.
Am J Surg Pathol 2003;27:1119–27.
[5] Saegusa H, Momose M, Kawa S, et al. Hilar and pancreatic gallium-67
accumulation is characteristic feature of autoimmune pancreatitis. Pancreas
2003;27:20–5.
[6] Takeda S, Haratake J, Kasai T, et al. IgG4-associated idiopathic tubulointerstitial
nephritis complicating autoimmune pancreatitis. Nephrol Dial Transplant
2004;19:474–6.
[7] Taniguchi T, Ko M, Seko S, et al. Interstitial pneumonia associated with
autoimmune pancreatitis.Gut 2004;53:770 [author reply 770–771].
[8] Uehara T, Hamano H, Kawa S, et al. Distinct clinicopathological entity
“autoimmune pancreatitis-associated sclerosing cholangitis”. Pathol Int
2005;55:405–11.
[9] Uehara T, Hamano H, Kawa S, et al. Chronic gastritis in the setting of autoimmune
pancreatitis. Am J Surg Pathol 2010;34:1241–9.
[10] Uehara T, Hamano H, Kawakami M, et al. Autoimmune pancreatitis-associated
prostatitis: distinct clinicopathological entity. Pathol Int 2008;58:118–25.
[11] Umemura T, Zen Y, Hamano H, et al. IgG4 associated autoimmune hepatitis: a
differential diagnosis for classical autoimmune hepatitis. Gut 2007;56:1471–2.
[12] Zen Y, Harada K, Sasaki M, et al. IgG4-related sclerosing cholangitis with and
without hepatic inflammatory pseudotumor, and sclerosing pancreatitis–associated sclerosing cholangitis: do they belong to a spectrum of sclerosing
pancreatitis? Am J Surg Pathol 2004;28:1193–203.
[13] Zen Y, Kitagawa S, Minato H, et al. IgG4-positive plasma cells in inflammatory
pseudotumor (plasma cell granuloma) of the lung. Hum Pathol 2005;36:710–7.
[14] Zhang L, Smyrk TC. Autoimmune pancreatitis and IgG4-related systemic diseases.
Int J Clin Exp Pathol 2010;3:491–504.
[15] Ito T, Nakano I, Koyanagi S, et al. Autoimmune pancreatitis as a new clinical entity.
Three cases of autoimmune pancreatitis with effective steroid therapy. Dig Dis Sci
1997;42:1458–68.
[16] Kawaguchi K, Koike M, Tsuruta K, et al. Lymphoplasmacytic sclerosing pancreatitis
with cholangitis: a variant of primary sclerosing cholangitis extensively involving
pancreas. Hum Pathol 1991;22:387–95.
[17] Cheuk W, Yuen HK, Chu SY, et al. Lymphadenopathy of IgG4-related sclerosing
disease. Am J Surg Pathol 2008;32:671–81.
[18] Sato Y, Notohara K, Kojima M, et al. IgG4-related disease: historical overview and
pathology of hematological disorders. Pathol Int 2010;60:247–58.
[19] Shimizu I, Nasu K, Sato K, et al. Lymphadenopathy of IgG4-related sclerosing
disease: three case reports and review of literature. Int J Hematol 2010;92:
751–6.
[20] Zen Y, Fujii T, Sato Y, et al. Pathological classification of hepatic inflammatory
pseudotumor with respect to IgG4-related disease. Mod Pathol 2007;20:
884–94.
[21] Sato Y, Kojima M, Takata K, et al. Immunoglobulin G4–related lymphadenopathy
with inflammatory pseudotumor-like features. Med Mol Morphol 2011;44:
179–82.
[22] Stone JH, Zen Y, Deshpande V. IgG4-related disease. N Engl J Med 2012;366:
539–51.
[23] Sakata N, Tashiro T, Uesugi N, et al. IgG4-positive plasma cells in inflammatory
abdominal aortic aneurysm: the possibility of an aortic manifestation of IgG4related sclerosing disease. Am J Surg Pathol 2008;32:553–9.
[24] Moran CA, Suster S, Abbondanzo SL. Inflammatory pseudotumor of lymph nodes:
a study of 25 cases with emphasis on morphological heterogeneity. Hum Pathol
1997;28:332–8.
[25] Zen Y, Nakanuma Y. IgG4-related disease: a cross-sectional study of 114 cases. Am
J Surg Pathol 2010;34:1812–9.