Use of samples from endoscopic ultrasound-guided 19-gauge fine-needle aspiration in diagnosis of autoimmune pancreatitis.
OBJECTIVE
Histologic techniques are used to distinguish autoimmune pancreatitis (AIP) from pancreatic malignancies and to confirm the etiology of pancreatitis. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a well-established technique used in the diagnosis of pancreatic cancer. However, it is unclear whether specimens obtained from pancreatic lesions by EUS-FNA are adequate for the histologic diagnosis of AIP, because the evaluation of tissue architecture and immunostaining assays usually require larger samples.


METHODS
We evaluated samples collected by EUS-FNA with a conventional 19-gauge needle by histologic analysis, looking for features of AIP. We analyzed data from 44 patients who were diagnosed with AIP and underwent EUS-FNA with a 19-gauge needle from January 2004 to September 2010. The FNA specimens were reviewed by histologic analysis; AIP was diagnosed based on the presence of lymphoplasmacytic sclerosing pancreatitis or immunoglobulin (Ig)G4-positive plasma cells in the infiltrate.


RESULTS
The specimen amount was inadequate from 3 patients. Among the remaining 41 patients, histopathologic analysis revealed lymphoplasmacytic sclerosing pancreatitis in 17 samples and IgG4-positive plasma cells in 5 (3 samples were positive for both); no samples had granulocytic epithelial lesions. Therefore, 19 patients (43%) were diagnosed with AIP based on histologic analysis. One patient had temporary abdominal pain.


CONCLUSIONS
EUS-FNA, with a 19-gauge needle, is a safe and reliable procedure for obtaining pancreatic samples for the histologic analysis of AIP. Although it does not have a high diagnostic yield, it might be useful in patients without typical features of AIP because it would allow patients to avoid surgery.
First Department of Internal Medicine, Gifu University Hospital, Gifu, Japan.
Takuji
T
Iwashita
Ichiro
I
Yasuda
Shinpei
S
Doi
Nobuhiro
N
Ando
Masanori
M
Nakashima
Seiji
S
Adachi
Yoshinobu
Y
Hirose
Tsuyoshi
T
Mukai
Keisuke
K
Iwata
Eiichi
E
Tomita
Takao
T
Itoi
Hisataka
H
Moriwaki
D000328:Adult; D000368:Aged; D001327:Autoimmune Diseases / Q000175:diagnosis*; D044963:Biopsy, Fine-Needle; D005260:Female; D006651:Histocytochemistry / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010195:Pancreatitis / Q000175:diagnosis*