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Hanaoka T, Okuwaki K, Imaizumi H, Imawari Y, Iwai T, Yamauchi H, Hasegawa R, Adachi K, Tadehara M, Kurosu T, Watanabe M, Tamaki A, Kida M, Koizumi W. Pancreatic Schwannoma Diagnosed by Endoscopic Ultrasound-guided Fine-needle Aspiration. Intern Med 2021; 60:1389-1395. [PMID: 33250465 PMCID: PMC8170256 DOI: 10.2169/internalmedicine.6129-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
A schwannoma is a tumor originating from Schwann cells. It is occasionally observed in the abdominal viscera in the form of a submucosal tumor derived from the gastric or duodenal muscularis propria. To date, only a few studies have reported on pancreatic schwannomas. Furthermore, very few patients are preoperatively diagnosed with pancreatic schwannoma because of the lack of established imaging characteristics distinguishing this type of schwannoma from other conditions. We herein report the first English publication of pancreatic schwannoma in which surgery was avoided because a pathological diagnosis was made solely on the basis of endoscopic ultrasound-guided fine-needle aspiration findings.
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Affiliation(s)
- Taro Hanaoka
- Department of Gastroenterology, Kitasato University School of Medicine, Japan
| | - Kosuke Okuwaki
- Department of Gastroenterology, Kitasato University School of Medicine, Japan
| | - Hiroshi Imaizumi
- Department of Gastroenterology, Kitasato University School of Medicine, Japan
- Department of Gastroenterology, JCHO Sagamino Hospital, Japan
| | - Yusuke Imawari
- Department of Gastroenterology, Kitasato University School of Medicine, Japan
- Department of Gastroenterology, JCHO Sagamino Hospital, Japan
| | - Tomohisa Iwai
- Department of Gastroenterology, Kitasato University School of Medicine, Japan
| | - Hiroshi Yamauchi
- Department of Gastroenterology, Kitasato University School of Medicine, Japan
| | - Rikiya Hasegawa
- Department of Gastroenterology, Kitasato University School of Medicine, Japan
| | - Kai Adachi
- Department of Gastroenterology, Kitasato University School of Medicine, Japan
| | - Masayoshi Tadehara
- Department of Gastroenterology, Kitasato University School of Medicine, Japan
| | - Takahiro Kurosu
- Department of Gastroenterology, Kitasato University School of Medicine, Japan
| | - Masafumi Watanabe
- Department of Gastroenterology, Kitasato University School of Medicine, Japan
| | - Akihiro Tamaki
- Department of Gastroenterology, Kitasato University School of Medicine, Japan
| | - Mitsuhiro Kida
- Department of Gastroenterology, Kitasato University School of Medicine, Japan
| | - Wasaburo Koizumi
- Department of Gastroenterology, Kitasato University School of Medicine, Japan
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Shi Z, Cao D, Zhuang Q, You R, Li X, Li Z, Li Y, Huang X. MR imaging features of pancreatic schwannoma: a Chinese case series and a systematic review of 25 cases. Cancer Imaging 2021; 21:23. [PMID: 33588954 PMCID: PMC7885599 DOI: 10.1186/s40644-021-00390-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/29/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND There is a paucity of existing literature centering on the magnetic resonance (MR) imaging features of pancreatic schwannomas, due to the neoplasm's nonspecific presentation and its rarity. We aimed to identify the characteristic imaging features of pancreatic schwannoma. METHODS This retrospective search was conducted for histologically confirmed pancreatic schwannoma in multi-institutional database of pathology. Abdominal magnetic resonance imaging (MRI) was performed before histologic examination and their MR imaging studies were independently reviewed. The search yielded six adults (mean age, 46 years) with a definitive histologic postoperative diagnosis of single pancreatic schwannoma each. Additionally, a comprehensive English and Chinese literature review for pancreatic schwannoma and reported MR-imaging findings since 1961 was also conducted. MR imaging features of those cases in the literature were analyzed, summarized and compared with our case series. RESULTS This rare entity appeared to be a well-circumscribed, exophytic, oval or round pancreatic mass with a mean greatest diameter of 3.7 cm. Five schwannomas were located in the pancreatic head-neck and one in the pancreatic tail. On MRI, all cases appeared hypointense on T1-weighted images, inhomogeneous hyperintense on T2-weighted images, and hyperintense on diffusion-weighted images. The mean apparent diffusion coefficient (ADC) values of pancreatic schwannoma were 1.11 ± 0.29 × 10- 3 mm2/s and significantly lower than the surrounding pancreas. The lesion-to-pancreas signal intensity ratio (SIR) at unenhanced T1-weighted images was 0.53 ± 0.07. On dynamic contrast-enhanced MRI, most of the lesions (67%, 4/6) showed homogeneously iso- or hypointense on arterial and portal venous phases, and hyperenhancement on delayed phase compared with the surrounding pancreas. In our analysis of the time intensity curves, all cases exhibited a gradual enhancement pattern. CONCLUSIONS A well-circumscribed mass displaying inhomogeneous hyperintensity on T2, marked hypointensity on T1, hyperintensity on DWI, and with early slight enhancement at arterial phase and progressive enhancement at portal venous and delayed phase, may suggest the diagnosis of pancreatic schwannoma.
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Affiliation(s)
- Zhenshan Shi
- Department of Radiology, The First Affiliated Hospital of Fujian Medical University, 20 Cha-Zhong Road, Fuzhou, 350005, Fujian, China
| | - Dairong Cao
- Department of Radiology, The First Affiliated Hospital of Fujian Medical University, 20 Cha-Zhong Road, Fuzhou, 350005, Fujian, China.
| | - Qian Zhuang
- Department of Pharmacy, Fujian Medical University Union Hospital, 29 Xin-Quan Road, Fuzhou, Fujian, China
| | - Ruixiong You
- Department of Radiology, The First Affiliated Hospital of Fujian Medical University, 20 Cha-Zhong Road, Fuzhou, 350005, Fujian, China
| | - Xiumei Li
- Department of Radiology, The First Affiliated Hospital of Fujian Medical University, 20 Cha-Zhong Road, Fuzhou, 350005, Fujian, China
| | - Zhongmin Li
- Department of Radiology, The First Affiliated Hospital of Fujian Medical University, 20 Cha-Zhong Road, Fuzhou, 350005, Fujian, China
| | - Yueming Li
- Department of Radiology, The First Affiliated Hospital of Fujian Medical University, 20 Cha-Zhong Road, Fuzhou, 350005, Fujian, China
| | - Xinming Huang
- Department of Radiology, Fujian Medical University Union Hospital, 29 Xin-Quan Road, Fuzhou, Fujian, China
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Azami T, Takano Y, Niiya F, Kobayashi T, Yamamura E, Maruoka N, Norose T, Ohike N, Nagahama M. A case of primary pancreatic schwannoma diagnosed by endoscopic ultrasound-fine needle aspiration. Clin J Gastroenterol 2020; 13:585-590. [PMID: 31983049 DOI: 10.1007/s12328-020-01095-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 01/10/2020] [Indexed: 01/27/2023]
Abstract
Pancreatic schwannoma is difficult to diagnose preoperatively. A 79-year-old man was found to have a 9-mm pancreatic mass on abdominal ultrasonography. On EUS, there was a 9-mm, clearly demarcated, round, solid, hypo-echoic mass in the pancreatic body. The differential diagnosis included a pancreatic neuroendocrine tumor, a solid-pseudopapillary neoplasm, and an atypical pancreatic cancer. EUS-FNA was performed with a 22G needle. On pathology examination, spindle-shaped tumor cells were seen proliferating in bundles. On immunostaining, the lesion was negative for c-kit, CD34, and α-SMA but positive for S-100 protein. The MIB-1 index was < 2%. Based on the above findings, the lesion was diagnosed as a benign pancreatic schwannoma. We, therefore, decided to follow the patient with careful observation rather than resecting the lesion surgically. The tumor has not changed significantly after 3 years of follow-up. EUS-FNA is useful for the diagnosis of pancreatic schwannoma. If the tumor can be determined to be benign preoperatively, unnecessary surgery can be avoided. EUS-FNA should be actively implemented for pancreatic tumors that are difficult to diagnose definitively on imaging.
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Affiliation(s)
- Tetsushi Azami
- Division of Gastroenterology, Department of Internal Medicine, Showa University Fujigaoka Hospital, 1-30 Fujigaoka, Aoba-ku, Yokohama-shi, Kanagawa, 227-8501, Japan.
| | - Yuichi Takano
- Division of Gastroenterology, Department of Internal Medicine, Showa University Fujigaoka Hospital, 1-30 Fujigaoka, Aoba-ku, Yokohama-shi, Kanagawa, 227-8501, Japan
| | - Fumitaka Niiya
- Division of Gastroenterology, Department of Internal Medicine, Showa University Fujigaoka Hospital, 1-30 Fujigaoka, Aoba-ku, Yokohama-shi, Kanagawa, 227-8501, Japan
| | - Takahiro Kobayashi
- Division of Gastroenterology, Department of Internal Medicine, Showa University Fujigaoka Hospital, 1-30 Fujigaoka, Aoba-ku, Yokohama-shi, Kanagawa, 227-8501, Japan
| | - Eiichi Yamamura
- Division of Gastroenterology, Department of Internal Medicine, Showa University Fujigaoka Hospital, 1-30 Fujigaoka, Aoba-ku, Yokohama-shi, Kanagawa, 227-8501, Japan
| | - Naotaka Maruoka
- Division of Gastroenterology, Department of Internal Medicine, Showa University Fujigaoka Hospital, 1-30 Fujigaoka, Aoba-ku, Yokohama-shi, Kanagawa, 227-8501, Japan
| | - Tomoko Norose
- Department of Diagnostic Pathology, Showa University Fujigaoka Hospital, Yokohama-shi, Kanagawa, Japan
| | - Nobuyuki Ohike
- Department of Diagnostic Pathology, Showa University Fujigaoka Hospital, Yokohama-shi, Kanagawa, Japan
| | - Masatsugu Nagahama
- Division of Gastroenterology, Department of Internal Medicine, Showa University Fujigaoka Hospital, 1-30 Fujigaoka, Aoba-ku, Yokohama-shi, Kanagawa, 227-8501, Japan
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