Final histologic diagnosis
Case 294
【Progress】
His symptoms worsened with increasing abdominal pain, ascites plus paralytic ileus. He was transported to university hospital for management.
He underwent surgical resection of pancreatic body and tail.
Histologic findings revealed intraductal mucinous neoplasm with high grade dysplasia.
【Discussion】
Pancreas cyst is often encountered in routine image interpretation on CT or MRI. Unilocular cyst emerges from true cyst, pseudocyst, and cystic tumors such as intraductal papillary mucinous neoplasm (IPMN), mucinous cyst adenoma, cystic endocrine tumor, lymphoepithelial tumor (1). Multilocular cyst emerges from serous cystadenoma. Mucinous cystadenoma and cystic solid papillary pseudotumor occurs predominantly significantly in female, while IPMN tend to occur in male rather than female (1).
Of these cystic lesions of pancreas, IPMN occurs most. IPMN is largely categorized four types: branch duct type, multifocal branch duct type, main duct type, and mixed type. Histologic type is classified into gastric type, intestinal type, pancreaticobiliary type, and oncocytic type (2). Further, IPMN is advanced from dysplasia to invasive cancer via in situ. Dysplasia advances from low grade, intermediate grade, and high grade, inducing neoplasm from in situ to invasive advanced cancer (2).
Intraoperative findings in the present case revealed remnant of cystic wall was found in the mesentery that indicated possible dissemination. The tumor was located in pancreatic tail. Macroscopically, it composed of multilocular cyst with papillary and flat-plate proliferation in the main duct and branch duct. The tumor is microscopically diagnosed to be invasive cancer surrounding high grade dysplasia of pancreaticobiliary type. Cystic tumor include mucin and hemosiderin indicating intraductal hemorrhage.
It is known that hemorrhage from pseudocyst occurs in 1.5% to 2% (1). At first, we misinterpreted the hemorrhage from pseudocyst with microaneurysm by erosion of pancreatitis on CT. However, MRI with fat suppression T2WI and diffusion WI depicted not only hemorrhage but viable tumor.
It is reported that IPMN with perforation and intraductal hemorrhage is rare, listed only seven cases including this case (2-9). Perforation might occur solely by elevating intraluminal pressure due to mucin production and hemorrhage. Hemorrhage might occur by immature tumor vessels or rupture of capsule interstitial vessels. Intraductal hemorrhage of IPMN whose size 2 cm or greater is reported to occur in the previous cases (2-9). In our case, tumor size was 68 mm (50mm, three years before). MRI with fat suppression T2WI and diffusion WI was useful to detect the presence of hematoma and viable tumor and distinct them. ADC values of tumors are 1.298-1.312, relatively higher than pancreas cancer of around 0.9 to 1.0.
Pancreas is one of the silent organs situated in retroperitoneal space. One of the representative pancreas tumors is obviously pancreatic cancer. As the other pancreatic tumors, neuroendocrine tumor, solid pseudopapillary tumor, intraductal papillary mucinous tumor (IPMN), mucinous cystadenoma (or cystadenocarcinoma), serous cystadenoma, are listed (10, 11). Of these, as cystic lesions, pseudocyst originated from pancreatitis, mucinous cystadenoma, serous cystadenoma, IPMN, solid pseudopapillary tumor and cystic neuroendocrine tumor, are listed (12-16).
Meanwhile, as the pancreatic lesions with hematoma, hemorrhagic pancreatitis (pseudocyst), hemorrhagic cystadenoma and solid pseudopapillary tumor, are listed (17, 18). Hemorrhage can occur when pancreas branch artery become eroded. MRI with T1WI and T2WI is useful to differentiate hematoma from other components because hematoma is demonstrated high signal intensity on T1WI and low signal intensity on T2WI. DWIMRI with ADC values can be useful to differentiate pancreas cancer from other pancreas tumors since ADC values of pancreas cancer around 1.0 to 1.1, while those of other pancreatic tumor are relatively high compared to pancreas cancer (19, 20).
In our case, non-enhanced CT depicted a cystic lesion with slight solid component plus slightly high attenuation component corresponded to hematoma. Contrast-enhanced CT depicted almost no enhancement of solid component and no extravasation of contrast medium but enlargement of pancreas tail branch artery. MRI demonstrated two types of component in a cystic lesion; one is visualized high signal intensity on T1WI and low signal intensity on T2WI, corresponded to hematoma: another is visualized iso signal intensity on T1WI and iso to slight low signal intensity on T2WI corresponded to cystic tumor. As hemorrhagic lesions as described above, hemorrhagic pseudocyst, cystic tumor hemorrhage and solitary pseudopapillary tumor are listed (12-20). The patient had no history of pancreatitis and no elevation of blood amylase, indicative of no possibility of pancreatitis. Solid pseudopapillary tumor is well-known to contain the components of hemorrhage and calcification (17-20). In our case, solid components are less in volume and cystic component are more, indicative of being not characteristic of solid pseudopapillary tumor. Morphologically, the present tumor mimics mucinous cystadenoma with hematoma, although it is not confirmed histologically.
As limitation, mucinous cystadenoma of the pancreas and solid pseudopapillary tumor of the pancreas appear often in female rather than in male. The gender of our case is male, indicating least possibility of mucinous cystadenoma and solid pseudopapillary tumor .
【Summary】
We presented a seventy three-year-old male for persistent pain in left lower abdomen. Laboratory test revealed white blood cells 16200/mm3, neutrophils 86.7%, CRP 0.41mg/dL, lipase 86 (12-53) U/L, Amylase 65 (44-132) U/L, indicative of inflammation. He was indicated to have cystic lesion at pancreatic tail. CT and MRI demonstrated cystic lesion with two types of solid components; one is hematoma; another, tumor-like lesion. He underwent surgical resection of pancreatic body and tail, indicative of diagnosis of intraductal papillary mucinous cancer surrounding high grade dysplasia.
It is borne in mind that except pancreatic cancer, five tumors of neuroendocrine tumor, solid pseudopapillary tumor, intraductal papillary mucinous neoplasm, mucinous cystadenoma and serous cystadenoma, are listed. As hemorrhagic lesions, hemorrhagic pancreatitis, solid papillary pseudotumor, mucinous cystadenoma, serous cyst adenoma, and IPMN, are listed. Gender might be important for differentiation: mucinous cystadenoma and cystic solid papillary pseudotumor predominantly occur in female. Although cystic hemorrhage is found most in pseudocyst, other hemorrhagic tumors including hemorrhagic cystadenoma, cystic solid pseudopapillary tumor, and IPMN can occur.
【References】
1.Bollen TL, et al. Radiological Workup of Cystic Neoplasms of the Pancreas. Visc Med. 2018 Jul; 34(3): 182–190
2.Tokue H, et al. Successful management of life-threatening bleeding of intraductal papillary mucinous neoplasms in the pancreatic head. SAGE Open Med Case Rep. 2017; 5: 2050313X17741014. Published online 2017 Nov 11. doi: 10.1177/2050313X17741014
3.Jianman Wu J, et al. Intraductal papillary mucinous neoplasm complicated with intraductal bleeding in a young woman mimicked a cystic solid pseudo-papillary tumor: a case report. BMC Gastroenterology volume 20, 2020 Article number: 304
4.Yamada Y, et al. Intraductal papillary mucinous neoplasms of the pancreas complicated with intraductal hemorrhage, perforation, and fistula formation: CT and MR imaging findings with pathologic correlation. Abdom Imaging 2012; 37(1): 100–109. 3. Tanaka M. Intraductal papillary mucinous neoplasm of the pancreas: diagnosis and treatment. Pancreas 2004; 28: 282–288.
5.Farrell JL, Brugge WR. Intraductal papillary mucinous tumor of the pancreas. Gastrointest Endosc 2002; 5: 701–714.
6.5. Jung IS, et al. Invasive intraductal papillary mucinous tumor of the pancreas with simultaneous invasion of the stomach and duodenum. Endoscopy 2004; 36(2): 186–189.
7.Kurihara K, et al. Biliopancreatic fistula associated with intraductal papillary-mucinous pancreatic cancer: institutional experience and review of the literature. Hepatogastroenterology 2000; 47: 1164–1167.
8.Lee SE, et al. Intraductal papillary mucinous carcinoma with atypical manifestations: report of two cases. World J Gastroenterol 2007; 13: 1622–1625
9.Kobayashi G, et al. Intraductal papillary mucinous neoplasms of the pancreas showing fistula formation into other organs. J Gastroenterol 2010; 45(10): 1080–1089.
10.Low G,et al. Multimodality imaging of neoplastic and nonneoplastic solid lesions of the pancreas. Radiographics. 2011;31:993–1015.
11.Vernuccio F, et al. Common and uncommon pitfalls in pancreatic imaging: it is not always cancer. Abdom Radiol (NY) 2016;41:283–294.
12.Barral M,et al. Magnetic resonance imaging of cystic pancreatic lesions in adults: an update in current diagnostic features and management. Abdom Imaging. 2014;39:48–65.
13.Bollen TL, et al. Radiological Workup of Cystic Neoplasms of the Pancreas. Visc Med. 2018 Jul; 34(3): 182–190
Scheiman JM, et al. American gastroenterological association technical review on the diagnosis and management of asymptomatic neoplastic pancreatic cysts. Gastroenterology. 2015;148:824–848.
14.Sahani DV, et al. Diagnosis and management of cystic pancreatic lesions. AJR Am J Roentgenol. 2013;200:343–354.
15.Kalb B, et al. MR imaging of cystic lesions of the pancreas. Radiographics. 2009;29:1749–1765.
16.Cantisani V, et al. American Journal of Roentgenology. 2003;181: 395-401MR Imaging Features of Solid Pseudopapillary Tumor of the Pancreas in Adult and Pediatric Patients.
17.American Journal of Roentgenology. 2003;181: 395-401
18.Ulusan S, et al. Case report: solid-pseudopapillary tumour of the pancreas associated with dorsal agenesis. Br J Radiol. 2005;78 (929): 441-443
19.Sandrasegaran K, et al. Diffusion-weighted imaging in characterization of cystic pancreatic lesions. Clin Radiol. 2011;66:808–814.
20.Pozzessere C, et al. Diffusion-weighted magnetic resonance imaging in distinguishing between mucin-producing and serous pancreatic cysts. J Comput Assist Tomogr.
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