Clin J Gastroenterol (2009) 2:232–237 DOI 10.1007/s12328-009-0078-8
CASE REPORT
A case of serous cystadenoma of the pancreas with a central stellate scar detected on contrast-enhanced ultrasound with perflubutane Hirofumi Yamanishi Æ Tomoyuki Yokota Æ Nobuaki Azemoto Æ Masashi Hirooka Æ Hidehiro Murakami Æ Yoichi Hiasa Æ Bunzo Matsuura Æ Morikazu Onji
Received: 18 November 2008 / Accepted: 23 February 2009 / Published online: 25 April 2009 Ó Springer 2009
Abstract An asymptomatic 66-year-old woman was admitted to our hospital for detailed evaluation of a 63-mm mass in the tail of the pancreas detected on abdominal computed tomography (CT). Abdominal ultrasound (US) revealed a hypoechoic solid mass, but on contrastenhanced ultrasound (CE-US) with perflubutane, a stellate structure within the tumor, characteristic of a serous cystadenoma, was observed. A distal pancreatectomy was performed, and histologic examination confirmed a serous cystadenoma of the pancreas. This case highlights the usefulness of CE-US with perflubutane for diagnosis of pancreatic serous cystadenomas.
imaging. Abdominal US and endoscopic US are important tools for diagnosis, but the use of CE-US with the new contrast agent perflubutane to detect the characteristic findings of serous cystadenomas has not previously been reported. We report a case in which a central stellate scar, a characteristic finding of pancreatic serous cystadenomas, was not visualized on other imaging studies, yet was clearly detected on CE-US with perflubutane. This case is reported to demonstrate the usefulness of CE-US with perflubutane to diagnose pancreatic serous cystadenomas.
Case report Keywords Perflubutane Serous cystadenoma Contrast-enhanced ultrasound Central stellate scar Pancreatic tumor
Introduction Pancreatic serous cystadenomas were first reported by Compagno et al. [1] in 1978. Serous cystadenomas are relatively rare pancreatic cystic tumors, but the number of reported cases has increased with advances in diagnostic
H. Yamanishi T. Yokota N. Azemoto Y. Hiasa B. Matsuura M. Onji (&) Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Toon, Ehime 791-0295, Japan e-mail: [email protected] M. Hirooka H. Murakami Department of Endoscopic Medicine, Ehime University Graduate School of Medicine, Toon, Ehime 791-0295, Japan
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Patient: A 66-year-old woman. Chief complaint: None (admitted for detailed evaluation of a mass lesion in the tail of the pancreas). Family history: Unremarkable. Past medical history: Unremarkable. Lifestyle habits: No smoking; social drinking. History of present illness: The patient was being treated by a local physician for hypertension. Since a screening abdominal US showed thickening of the gallbladder wall, she was referred to our outpatient department for further evaluation. Abdominal CT of the gallbladder showed adenomyosis, but a 63-mm cystic lesion was also noted in the tail of the pancreas. She was admitted to the hospital for further evaluation. Findings on admission: Height 146 cm, weight 57.4 kg, blood pressure 124/76 mmHg, pulse 72/min, and temperature 36.8°C. There was no conjunctival pallor or scleral icterus. Heart and breath sounds were normal. The abdomen was flat, soft, and nontender, and no masses were palpable. Laboratory tests on admission: Hematology, clinical chemistry, and pancreatic enzyme values were normal.
Clin J Gastroenterol (2009) 2:232–237
Anti-hepatitis C virus (HCV) antibody was positive. Carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), Duke Pancreas-2 (DUPAN-II), sialyl Lewis X (SLX), and S-pancreas-1 antigen (SPAN-I) levels were within normal limits. Abdominal ultrasound (US): An approximately 65-mm, well-demarcated lesion with regular margins was seen in the tail of the pancreas. The lesion appeared solid with relatively uniform hypoechogenicity (Fig. 1a). Endoscopic ultrasound (EUS): The tumor margins showed clusters of microcysts, but the center of the lesion was hyperechoic (Fig. 1b). Abdominal CT: A mass was present in the tail of the pancreas. Plain CT showed low density (Fig. 2a). Contrast CT during the late phase revealed septal enhancement with honeycomb appearance and no infiltration to the surroundings (Fig. 2b). There was no calcification in the center of the lesion. In addition, in the S3 segment of the liver, blushing during the arterial phase and washout during the late phase were observed. Abdominal magnetic resonance imaging (MRI): A cystic lesion similar to that on CT was observed. The lumen was hypointense on T1 weighting and hyperintense on T2 weighting. Endoscopic retrograde pancreatography (ERP): No dilation of the major papilla or mucus outflow was noted. Dilation of the main pancreatic duct and communication with the cyst were not observed, but in the tail of the pancreas the main pancreatic duct was deviated due to compression by the mass (Fig. 3). Abdominal angiography: Abdominal angiography was performed to exclude hepatocellular carcinoma. The arterial phase blushing of liver segment S3 seen on abdominal CT was probably an A-P shunt. Celiac angiography showed blushing that corresponded to the identified pancreatic tumor (Fig. 4). Contrast-enhanced ultrasound (CE-US): CE-US with perflubutane was performed to obtain more detailed
233
information on ultrasonography. There was gradual enhancement within the tumor from 1 min 30 sec after injection of perflubutane. At 1 min 38 sec, a septum, appearing as a central stellate scar radiating from the center of the tumor, was clearly seen (Fig. 5). Clinical course: The above imaging findings were consistent with a differential diagnosis of pancreatic serous cystadenoma, intraductal papillary mucinous neoplasm (IPMN) or mucinous cystadenoma (MCN). The morphology of the cyst made IPMN unlikely, but it was listed because abdominal CT and EUS revealed microcystic clusters. MCN was mentioned because the patient was a middle-aged woman with a lesion in the tail of the pancreas, and abdominal US and CT showed a spherical cyst. However, the central stellate scar on CE-US, the microcystic clusters on EUS, and the honeycomb appearance on abdominal contrast CT suggested that a pancreatic serous cystadenoma was most likely. These tumors are benign in most cases [2, 3]. However, in this case, the pancreatic duct in the tail of the pancreas was compressed and could have possibly led to future obstruction; the tumor was [3 cm [4] and the patient and her family strongly wanted the tumor to be removed. Therefore, after obtaining informed consent, a distal pancreatectomy was performed in our Department of Surgery. Histopathologic findings: A well-demarcated, spongy tumor, measuring 72 9 65 mm, with a central stellate scar, was present in the tail of the pancreas (Fig. 6). Histologic examination showed that the tumor was composed of microcysts. The cyst diameter was greater near the tumor margins than at the center. The cyst wall was covered with a single layer of simple columnar epithelium. No papillary hyperplasia or cellular atypia was seen within the tumor. Staining with various antibodies to blood vessels showed a rich blood supply in the cyst septa (Fig. 7). The histologic diagnosis was serous cystadenoma (microcystic type).
Fig. 1 Abdominal ultrasound (epigastric transverse scan). a An approximately 65-mm, well-demarcated lesion with regular margins is seen in the tail of the pancreas. The lesion appears solid with relatively uniform hypoechogenicity. b Endoscopic ultrasound shows a nonechogenic area indicative of microcystic clusters near the probe
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Fig. 2 Abdominal CT. a Lowdensity mass in the tail of the pancreas b Contrast CT during the late phase reveals septal enhancement within the lesion, with honeycomb appearance
Fig. 4 Abdominal angiography celiac angiography shows blushing corresponding to the tumor site (arrowheads) Fig. 3 Endoscopic retrograde pancreatography in the tail of the pancreas: the main pancreatic duct is deviated due to compression by the mass (arrow)
Discussion Pancreatic serous cystadenomas are round or oval-shaped tumors with honeycomb-like structure, and detection of these characteristic features is key to the imaging diagnosis. In addition to honeycomb appearance, other typical features may include a central stellate scar and calcification [5, 6]. However, a high degree of diagnostic reliability is crucial. On ultrasound, the diagnosis was correct in 53% of the cases, incorrect in 31%, and nondiagnostic in 16% [7]. In the present case, the tumor appeared as a homogenous hypoechoic mass on abdominal US, and it was difficult to make a definite diagnosis. On EUS, it was possible to observe the cyst near the surface of the tumor, and although the center was depicted as a hyperechoic lesion, no stellate scar could be seen. CE-US with perflubutane was performed to obtain more detailed information on ultrasonography. CE-US with
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perflubutane enabled observation of the entire tumor and depicted the central stellate scar distinctly, which abdominal US and EUS could not. Other pancreatic tumors, particularly ductal adenocarcinoma and neuroendocrine carcinoma, present heterogeneous enhancement on CE-US. However, in this case, the tumor interior initially showed heterogeneous contrast enhancement, and the central stellate scar was enhanced with contrast over time. Because stellate scars are seen in about half of serous cystadenomas of the pancreas and are not seen with other pancreatic tumors, contrastenhanced US using perflubutane was useful for diagnosing the serous cystadenoma. In pancreatic serous cystadenomas, the septa between the microcysts are thin and fibrous, and they have rich vascularity. This accounts for the honeycomb appearance in the tumor interior on contrast CT. Moreover, in 45% of cases of pancreatic serous cystadenoma, small septal nodules and a central stellate scar are present [8]. In the present patient, histopathologic examination showed a spongy tumor with a central stellate scar, and tissue staining with
Clin J Gastroenterol (2009) 2:232–237
235
Fig. 5 Contrast-enhanced ultrasound (CE-US). a Precontrast. b 1 min 31 s after contrast injection. c 1 min 33 s after contrast injection. d 1 min 38 s after contrast injection, a central stellate scar is seen within the tumor
Fig. 6 Macroscopic finding of resected specimen: a well-demarcated, spongy tumor, measuring 72 9 65 mm, with a central stellate scar, was present in the tail of the pancreas
antibodies to blood vessels revealed rich vascularity of the septa, including the central stellate scar. Thus, the stellar structure detected on CE-US was indeed a central stellate scar. EUS uses high frequencies to image lesions, can clearly detect findings such as microcyst clusters, and may be very
useful in diagnosing serous cystadenomas [9, 10]. In the present patient, clusters of cysts with a larger diameter were present at the tumor margins, whereas clusters of cysts at a more microscopic level in the center appeared as a hyperechoic area. However, the central stellate scar could not be visualized on EUS. Contrast CT depicted a clear honeycomb appearance, and on MRI, T1-WI showed hypointensity, and T2-WI showed marked hyperintensity. These findings are typical of a pancreatic serous cystadenoma [3, 10, 11]. However, these imaging modalities failed to detect the central stellate scar, which could only be visualized on CE-US. In our review of Medline (1983 to February 2008) on CE-US with Levovist (galactose/palmitic acid) or perflubutane for evaluation of pancreatic serous cystadenomas, there were no reports of detection of a central stellate scar for comparison with histologic findings. Perflubutane has low solubility, has a shell, and has a longer blood flow enhancement time than Levovist. Levovist requires a high mechanical index (MI) for contrast, so real-time imaging is possible only with rapid blood flow. On the other hand, perflubutane resonates at a low MI for contrast, so longer real-time imaging is possible with rapid or slower blood flow [12–14]. The size of blood vessels in the stroma of
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Fig. 7 Histopathologic examination. a The tumor is composed of microcysts; the cyst diameter is greater near the tumor margins than at the center (magnified image). b The cyst wall is covered by a single layer of simple columnar epithelium. No papillary hyperplasia or cellular atypia is seen within the lesion [hematoxylin and eosin (H&E) 9400]. Staining with antibodies to blood vessels shows a rich blood supply in the cyst septa (c F-VIII RA 9100, d anti-CD31 antibody 9100)
pancreatic serous cystadenomas varies, so that the hemodynamic characteristics also differ. Given these various hemodynamic characteristics, perflubutane may be preferable to Levovist for detecting the characteristic findings of pancreatic serous cystadenomas. In the present patient, CE-US with perflubutane clearly depicted a central stellate scar that other imaging modalities failed to detect. Histopathologic examination showed the characteristic findings of a serous cystadenoma (microcystic type). This case highlights the usefulness of CE-US with perflubutane to diagnose pancreatic serous cystadenomas. In cases in which contrast CT and MRI are contraindicated, CE-US with perflubutane appears to be a comparatively safe imaging modality to use to support a diagnosis of pancreatic serous cystadenoma. However, further studies are required to determine whether the finding in this case is generally observed in pancreatic serous cystadenomas with a central stellate scar. The diagnosis of pancreatic serous cystadenomas, particularly their differential diagnosis from ductal adenocarcinoma and neuroendocrine carcinoma, should be made carefully using a combination of imaging modalities.
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References 1. Compagno J, Oertel JE. Microcystic adenomas of the pancreas (glycogen-rich cystadenomas): a clinicopathologic study of 34 cases. Am J Clin Pathol. 1978;69(3):289–98. 2. Alpert LC, Truong LD, Bossart MI, Spjut HJ. Microcystic adenoma (serous cystadenoma) of the pancreas a study of 14 cases with immunohistochemical and electron-microscopic correlation. Am J Surg Pathol. 1988;12(4):251–63. 3. Gourgiotis S, Germanos S, Ridolfini MP. Presentation management of pancreatic cystic neoplasma. J Clin Gastroenterol. 2007;41(6):599–608. 4. Fujii H, Kubo S, Hirohashi K, Kinoshita H, Yamamoto T, Wakasa K. Serous cystadenoma of the pancreas with atypical cells. Int J Pancreatol. 1988;23(2):165–9. 5. Itai Y, Ohhashi K, Furui S, Araki T, Murakami Y, Ohtomo K, et al. Microcystic adenoma of the pancreas: spectrum of computed tomographic findings. J Comput Assist Tomogr. 1988; 12(5):797–803. 6. Procacci C, Graziani R, Bicego E, Bergamo-Andreis IA, Guarise A, Valdo M, et al. Serous cystadenoma of the pancreas: report of 30 cases with emphasis on the imaging findings. J Comput Assist Tomogr. 1997;21(3):373–82. 7. Bassi C, Salvia R, Molinari E, Biasutti C, Falconi M, Pederzoli P. Management of 100 consecutive cases of pancreatic serous cystadenoma: wait for symptoms and see at imaging or vice versa? World J Surg. 2003;27(3):319–23.
Clin J Gastroenterol (2009) 2:232–237 8. Yasuhara Y, Sakaida N, Uemura Y, Senzaki H, Shikata N, Tsubura A. Serous microcystic adenoma (glycogen-rich cystadenoma) of the pancreas: study of 11 cases showing clinicopathological and immunohistochemical correlations. Pathol Int. 2002;52(4):307–12. 9. Koito K, Ichimura T, Hirokawa N, Syonai T, Mukaiya M, Shimizu K. A small serous cystadenoma of the pancreas: endoscopic ultrasonographic findings. Pancreas. 2000;21(1):101–3. 10. Le Borgne J, de Calan L, Partensky C. Cystadenomas and cystadenocarcinomas of the pancreas: a multiinstitutional retrospective study of 398 cases French Surgical Association. Ann Surg. 1999;230(2):152–61. 11. Zhong L. Magnetic resonance imaging in the detection of pancreatic neoplasms. J Dig Dis. 2007;8(3):128–32.
237 12. Nicolau C, Vilana R, Catala´ V, Bianchi L, Gilabert R, Garcı´a A, et al. Importance of evaluating all vascular phases on contrastenhanced sonography in the differentiation of benign from malignant focal liver lesions. AJR Am J Roentgenol. 2006; 186:158–67. 13. Sontum PC. Physicochemical characteristics of Sonazoid, a new contrast agent for ultrasound imaging. Ultrasound Med Biol. 2008;34(5):824–33. 14. Edey AJ, Ryan SM, Beese RC, Gordon P, Sidhu PS. Ultrasound imaging of liver metastases in the delayed parenchymal phase following administration of Sonazoid using a destructive mode technique (Agent Detection Imaging). Clin Radiol. 2008;63 (10):1112–20.
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CASE REPORT
A case of serous cystadenoma of the pancreas with a central stellate scar detected on contrast-enhanced ultrasound with perflubutane Hirofumi Yamanishi Æ Tomoyuki Yokota Æ Nobuaki Azemoto Æ Masashi Hirooka Æ Hidehiro Murakami Æ Yoichi Hiasa Æ Bunzo Matsuura Æ Morikazu Onji
Received: 18 November 2008 / Accepted: 23 February 2009 / Published online: 25 April 2009 Ó Springer 2009
Abstract An asymptomatic 66-year-old woman was admitted to our hospital for detailed evaluation of a 63-mm mass in the tail of the pancreas detected on abdominal computed tomography (CT). Abdominal ultrasound (US) revealed a hypoechoic solid mass, but on contrastenhanced ultrasound (CE-US) with perflubutane, a stellate structure within the tumor, characteristic of a serous cystadenoma, was observed. A distal pancreatectomy was performed, and histologic examination confirmed a serous cystadenoma of the pancreas. This case highlights the usefulness of CE-US with perflubutane for diagnosis of pancreatic serous cystadenomas.
imaging. Abdominal US and endoscopic US are important tools for diagnosis, but the use of CE-US with the new contrast agent perflubutane to detect the characteristic findings of serous cystadenomas has not previously been reported. We report a case in which a central stellate scar, a characteristic finding of pancreatic serous cystadenomas, was not visualized on other imaging studies, yet was clearly detected on CE-US with perflubutane. This case is reported to demonstrate the usefulness of CE-US with perflubutane to diagnose pancreatic serous cystadenomas.
Case report Keywords Perflubutane Serous cystadenoma Contrast-enhanced ultrasound Central stellate scar Pancreatic tumor
Introduction Pancreatic serous cystadenomas were first reported by Compagno et al. [1] in 1978. Serous cystadenomas are relatively rare pancreatic cystic tumors, but the number of reported cases has increased with advances in diagnostic
H. Yamanishi T. Yokota N. Azemoto Y. Hiasa B. Matsuura M. Onji (&) Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Toon, Ehime 791-0295, Japan e-mail: [email protected] M. Hirooka H. Murakami Department of Endoscopic Medicine, Ehime University Graduate School of Medicine, Toon, Ehime 791-0295, Japan
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Patient: A 66-year-old woman. Chief complaint: None (admitted for detailed evaluation of a mass lesion in the tail of the pancreas). Family history: Unremarkable. Past medical history: Unremarkable. Lifestyle habits: No smoking; social drinking. History of present illness: The patient was being treated by a local physician for hypertension. Since a screening abdominal US showed thickening of the gallbladder wall, she was referred to our outpatient department for further evaluation. Abdominal CT of the gallbladder showed adenomyosis, but a 63-mm cystic lesion was also noted in the tail of the pancreas. She was admitted to the hospital for further evaluation. Findings on admission: Height 146 cm, weight 57.4 kg, blood pressure 124/76 mmHg, pulse 72/min, and temperature 36.8°C. There was no conjunctival pallor or scleral icterus. Heart and breath sounds were normal. The abdomen was flat, soft, and nontender, and no masses were palpable. Laboratory tests on admission: Hematology, clinical chemistry, and pancreatic enzyme values were normal.
Clin J Gastroenterol (2009) 2:232–237
Anti-hepatitis C virus (HCV) antibody was positive. Carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), Duke Pancreas-2 (DUPAN-II), sialyl Lewis X (SLX), and S-pancreas-1 antigen (SPAN-I) levels were within normal limits. Abdominal ultrasound (US): An approximately 65-mm, well-demarcated lesion with regular margins was seen in the tail of the pancreas. The lesion appeared solid with relatively uniform hypoechogenicity (Fig. 1a). Endoscopic ultrasound (EUS): The tumor margins showed clusters of microcysts, but the center of the lesion was hyperechoic (Fig. 1b). Abdominal CT: A mass was present in the tail of the pancreas. Plain CT showed low density (Fig. 2a). Contrast CT during the late phase revealed septal enhancement with honeycomb appearance and no infiltration to the surroundings (Fig. 2b). There was no calcification in the center of the lesion. In addition, in the S3 segment of the liver, blushing during the arterial phase and washout during the late phase were observed. Abdominal magnetic resonance imaging (MRI): A cystic lesion similar to that on CT was observed. The lumen was hypointense on T1 weighting and hyperintense on T2 weighting. Endoscopic retrograde pancreatography (ERP): No dilation of the major papilla or mucus outflow was noted. Dilation of the main pancreatic duct and communication with the cyst were not observed, but in the tail of the pancreas the main pancreatic duct was deviated due to compression by the mass (Fig. 3). Abdominal angiography: Abdominal angiography was performed to exclude hepatocellular carcinoma. The arterial phase blushing of liver segment S3 seen on abdominal CT was probably an A-P shunt. Celiac angiography showed blushing that corresponded to the identified pancreatic tumor (Fig. 4). Contrast-enhanced ultrasound (CE-US): CE-US with perflubutane was performed to obtain more detailed
233
information on ultrasonography. There was gradual enhancement within the tumor from 1 min 30 sec after injection of perflubutane. At 1 min 38 sec, a septum, appearing as a central stellate scar radiating from the center of the tumor, was clearly seen (Fig. 5). Clinical course: The above imaging findings were consistent with a differential diagnosis of pancreatic serous cystadenoma, intraductal papillary mucinous neoplasm (IPMN) or mucinous cystadenoma (MCN). The morphology of the cyst made IPMN unlikely, but it was listed because abdominal CT and EUS revealed microcystic clusters. MCN was mentioned because the patient was a middle-aged woman with a lesion in the tail of the pancreas, and abdominal US and CT showed a spherical cyst. However, the central stellate scar on CE-US, the microcystic clusters on EUS, and the honeycomb appearance on abdominal contrast CT suggested that a pancreatic serous cystadenoma was most likely. These tumors are benign in most cases [2, 3]. However, in this case, the pancreatic duct in the tail of the pancreas was compressed and could have possibly led to future obstruction; the tumor was [3 cm [4] and the patient and her family strongly wanted the tumor to be removed. Therefore, after obtaining informed consent, a distal pancreatectomy was performed in our Department of Surgery. Histopathologic findings: A well-demarcated, spongy tumor, measuring 72 9 65 mm, with a central stellate scar, was present in the tail of the pancreas (Fig. 6). Histologic examination showed that the tumor was composed of microcysts. The cyst diameter was greater near the tumor margins than at the center. The cyst wall was covered with a single layer of simple columnar epithelium. No papillary hyperplasia or cellular atypia was seen within the tumor. Staining with various antibodies to blood vessels showed a rich blood supply in the cyst septa (Fig. 7). The histologic diagnosis was serous cystadenoma (microcystic type).
Fig. 1 Abdominal ultrasound (epigastric transverse scan). a An approximately 65-mm, well-demarcated lesion with regular margins is seen in the tail of the pancreas. The lesion appears solid with relatively uniform hypoechogenicity. b Endoscopic ultrasound shows a nonechogenic area indicative of microcystic clusters near the probe
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Fig. 2 Abdominal CT. a Lowdensity mass in the tail of the pancreas b Contrast CT during the late phase reveals septal enhancement within the lesion, with honeycomb appearance
Fig. 4 Abdominal angiography celiac angiography shows blushing corresponding to the tumor site (arrowheads) Fig. 3 Endoscopic retrograde pancreatography in the tail of the pancreas: the main pancreatic duct is deviated due to compression by the mass (arrow)
Discussion Pancreatic serous cystadenomas are round or oval-shaped tumors with honeycomb-like structure, and detection of these characteristic features is key to the imaging diagnosis. In addition to honeycomb appearance, other typical features may include a central stellate scar and calcification [5, 6]. However, a high degree of diagnostic reliability is crucial. On ultrasound, the diagnosis was correct in 53% of the cases, incorrect in 31%, and nondiagnostic in 16% [7]. In the present case, the tumor appeared as a homogenous hypoechoic mass on abdominal US, and it was difficult to make a definite diagnosis. On EUS, it was possible to observe the cyst near the surface of the tumor, and although the center was depicted as a hyperechoic lesion, no stellate scar could be seen. CE-US with perflubutane was performed to obtain more detailed information on ultrasonography. CE-US with
123
perflubutane enabled observation of the entire tumor and depicted the central stellate scar distinctly, which abdominal US and EUS could not. Other pancreatic tumors, particularly ductal adenocarcinoma and neuroendocrine carcinoma, present heterogeneous enhancement on CE-US. However, in this case, the tumor interior initially showed heterogeneous contrast enhancement, and the central stellate scar was enhanced with contrast over time. Because stellate scars are seen in about half of serous cystadenomas of the pancreas and are not seen with other pancreatic tumors, contrastenhanced US using perflubutane was useful for diagnosing the serous cystadenoma. In pancreatic serous cystadenomas, the septa between the microcysts are thin and fibrous, and they have rich vascularity. This accounts for the honeycomb appearance in the tumor interior on contrast CT. Moreover, in 45% of cases of pancreatic serous cystadenoma, small septal nodules and a central stellate scar are present [8]. In the present patient, histopathologic examination showed a spongy tumor with a central stellate scar, and tissue staining with
Clin J Gastroenterol (2009) 2:232–237
235
Fig. 5 Contrast-enhanced ultrasound (CE-US). a Precontrast. b 1 min 31 s after contrast injection. c 1 min 33 s after contrast injection. d 1 min 38 s after contrast injection, a central stellate scar is seen within the tumor
Fig. 6 Macroscopic finding of resected specimen: a well-demarcated, spongy tumor, measuring 72 9 65 mm, with a central stellate scar, was present in the tail of the pancreas
antibodies to blood vessels revealed rich vascularity of the septa, including the central stellate scar. Thus, the stellar structure detected on CE-US was indeed a central stellate scar. EUS uses high frequencies to image lesions, can clearly detect findings such as microcyst clusters, and may be very
useful in diagnosing serous cystadenomas [9, 10]. In the present patient, clusters of cysts with a larger diameter were present at the tumor margins, whereas clusters of cysts at a more microscopic level in the center appeared as a hyperechoic area. However, the central stellate scar could not be visualized on EUS. Contrast CT depicted a clear honeycomb appearance, and on MRI, T1-WI showed hypointensity, and T2-WI showed marked hyperintensity. These findings are typical of a pancreatic serous cystadenoma [3, 10, 11]. However, these imaging modalities failed to detect the central stellate scar, which could only be visualized on CE-US. In our review of Medline (1983 to February 2008) on CE-US with Levovist (galactose/palmitic acid) or perflubutane for evaluation of pancreatic serous cystadenomas, there were no reports of detection of a central stellate scar for comparison with histologic findings. Perflubutane has low solubility, has a shell, and has a longer blood flow enhancement time than Levovist. Levovist requires a high mechanical index (MI) for contrast, so real-time imaging is possible only with rapid blood flow. On the other hand, perflubutane resonates at a low MI for contrast, so longer real-time imaging is possible with rapid or slower blood flow [12–14]. The size of blood vessels in the stroma of
123
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Fig. 7 Histopathologic examination. a The tumor is composed of microcysts; the cyst diameter is greater near the tumor margins than at the center (magnified image). b The cyst wall is covered by a single layer of simple columnar epithelium. No papillary hyperplasia or cellular atypia is seen within the lesion [hematoxylin and eosin (H&E) 9400]. Staining with antibodies to blood vessels shows a rich blood supply in the cyst septa (c F-VIII RA 9100, d anti-CD31 antibody 9100)
pancreatic serous cystadenomas varies, so that the hemodynamic characteristics also differ. Given these various hemodynamic characteristics, perflubutane may be preferable to Levovist for detecting the characteristic findings of pancreatic serous cystadenomas. In the present patient, CE-US with perflubutane clearly depicted a central stellate scar that other imaging modalities failed to detect. Histopathologic examination showed the characteristic findings of a serous cystadenoma (microcystic type). This case highlights the usefulness of CE-US with perflubutane to diagnose pancreatic serous cystadenomas. In cases in which contrast CT and MRI are contraindicated, CE-US with perflubutane appears to be a comparatively safe imaging modality to use to support a diagnosis of pancreatic serous cystadenoma. However, further studies are required to determine whether the finding in this case is generally observed in pancreatic serous cystadenomas with a central stellate scar. The diagnosis of pancreatic serous cystadenomas, particularly their differential diagnosis from ductal adenocarcinoma and neuroendocrine carcinoma, should be made carefully using a combination of imaging modalities.
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References 1. Compagno J, Oertel JE. Microcystic adenomas of the pancreas (glycogen-rich cystadenomas): a clinicopathologic study of 34 cases. Am J Clin Pathol. 1978;69(3):289–98. 2. Alpert LC, Truong LD, Bossart MI, Spjut HJ. Microcystic adenoma (serous cystadenoma) of the pancreas a study of 14 cases with immunohistochemical and electron-microscopic correlation. Am J Surg Pathol. 1988;12(4):251–63. 3. Gourgiotis S, Germanos S, Ridolfini MP. Presentation management of pancreatic cystic neoplasma. J Clin Gastroenterol. 2007;41(6):599–608. 4. Fujii H, Kubo S, Hirohashi K, Kinoshita H, Yamamoto T, Wakasa K. Serous cystadenoma of the pancreas with atypical cells. Int J Pancreatol. 1988;23(2):165–9. 5. Itai Y, Ohhashi K, Furui S, Araki T, Murakami Y, Ohtomo K, et al. Microcystic adenoma of the pancreas: spectrum of computed tomographic findings. J Comput Assist Tomogr. 1988; 12(5):797–803. 6. Procacci C, Graziani R, Bicego E, Bergamo-Andreis IA, Guarise A, Valdo M, et al. Serous cystadenoma of the pancreas: report of 30 cases with emphasis on the imaging findings. J Comput Assist Tomogr. 1997;21(3):373–82. 7. Bassi C, Salvia R, Molinari E, Biasutti C, Falconi M, Pederzoli P. Management of 100 consecutive cases of pancreatic serous cystadenoma: wait for symptoms and see at imaging or vice versa? World J Surg. 2003;27(3):319–23.
Clin J Gastroenterol (2009) 2:232–237 8. Yasuhara Y, Sakaida N, Uemura Y, Senzaki H, Shikata N, Tsubura A. Serous microcystic adenoma (glycogen-rich cystadenoma) of the pancreas: study of 11 cases showing clinicopathological and immunohistochemical correlations. Pathol Int. 2002;52(4):307–12. 9. Koito K, Ichimura T, Hirokawa N, Syonai T, Mukaiya M, Shimizu K. A small serous cystadenoma of the pancreas: endoscopic ultrasonographic findings. Pancreas. 2000;21(1):101–3. 10. Le Borgne J, de Calan L, Partensky C. Cystadenomas and cystadenocarcinomas of the pancreas: a multiinstitutional retrospective study of 398 cases French Surgical Association. Ann Surg. 1999;230(2):152–61. 11. Zhong L. Magnetic resonance imaging in the detection of pancreatic neoplasms. J Dig Dis. 2007;8(3):128–32.
237 12. Nicolau C, Vilana R, Catala´ V, Bianchi L, Gilabert R, Garcı´a A, et al. Importance of evaluating all vascular phases on contrastenhanced sonography in the differentiation of benign from malignant focal liver lesions. AJR Am J Roentgenol. 2006; 186:158–67. 13. Sontum PC. Physicochemical characteristics of Sonazoid, a new contrast agent for ultrasound imaging. Ultrasound Med Biol. 2008;34(5):824–33. 14. Edey AJ, Ryan SM, Beese RC, Gordon P, Sidhu PS. Ultrasound imaging of liver metastases in the delayed parenchymal phase following administration of Sonazoid using a destructive mode technique (Agent Detection Imaging). Clin Radiol. 2008;63 (10):1112–20.
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