Imaging Features of Primary Malignant Pancreatic Tumors in Children

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1 Pediatric Imaging linical Perspective Ozcan et al. Pancreatic Tumors in hildren Pediatric Imaging linical Perspective Hatice Nursun Ozcan 1 erna Oguz 1 Hilal Susam Sen 2 anan kyuz 2 Mithat Haliloglu 1 Ozcan HN, Oguz, Sen HS, kyuz, Haliloglu M Keywords: T, MRI, pancreas, pediatric, tumors, ultrasound OI: /JR Received November 28, 2013; accepted after revision January 1, epartment of Radiology, ivision of Pediatric Radiology, Hacettepe University Medical School, Sıhhiye 06100, nkara, Turkey. ddress correspondence to M. Haliloglu (mithath@hacettepe.edu.tr). 2 epartment of Pediatric Oncology, Hacettepe University Medical School, nkara, Turkey. JR 2014; 203: X/14/ merican Roentgen Ray Society Imaging Features of Primary Malignant Pancreatic Tumors in hildren OJETIVE. The purpose of this article is to describe the sonographic, T, and MRI features of primary malignant pancreatic tumors of childhood. ONLUSION. Most children with a pancreatic tumor present with a solid pseudopapillary tumor that is usually well marginated and has solid and cystic areas surrounded by a fibrous capsule. Pancreatoblastoma is more aggressive than solid pseudopapillary tumor. The imaging features are those of a large heterogeneous tumor. uctal adenocarcinoma is rare in children and has a poor prognosis. P ancreatic tumors, which cause less than 0.2% of cancer-related pediatric deaths, are rarely seen in children. They have a different histologic spectrum and better clinical outcome than pancreatic tumors in adults. Primary pancreatic tumors are divided into epithelial (exocrine or endocrine) and nonepithelial types. Epithelial tumors are either derived from ductal and acinar cells or have an undetermined cell origin [1]. The two most common tumors in this group are solid pseudopapillary tumor (SPT) and pancreatoblastoma. Nonepithelial tumors arising primarily from the pancreas are rare in children. These include lymphoma, primitive neuroectodermal tumor, and mesenchymal tumors [2]. In addition, although uncommon, metastatic involvement of the pancreas is also seen in childhood. The pertinent malignancies are lymphomas and sarcomas. urkitt lymphoma and rhabdomyosarcoma are the most common. In the literature, the reported studies of pancreatic tumors are mainly found in the surgical literature [3 7]. Few studies have been conducted on imaging findings of pediatric pancreatic tumors, and they have included all types of tumoral involvement (i.e., benign, malignant, and metastatic) [2, 8, 9]. The purpose of this article is to review only primary malignant pancreatic tumors seen over 22 years at our institution. We have rendered the sonographic, T, and MRI findings in correlation with the pathologic findings. Materials and Methods The archives in the pediatric oncology unit were searched for primary malignant pancreatic tumors documented in the 22 years This search yielded the cases of 15 patients, five of whom did not have imaging studies available. The other 10 patients (nine girls, one boy; age range, 2 14 years; mean age, 9.6 years) were included in this study. emographic features, imaging findings, and pathologic confirmation of the diagnosis were recorded. Imaging features at sonography, T, and MRI were evaluated for the following characteristics: location within the pancreas, tumor margins and heterogeneity, presence of a capsule, calcifications, enhancement, ascites, biliary or pancreatic ductal dilatation, lymphadenopathy, displacement or encasement of visceral vessels, and presence and location of metastasis. On contrast-enhanced T images, enhancement was noted if portions of the tumor were isoattenuating in relation to the adjacent vascular structures. The pancreatic localizations were classified as being at the head, body, or tail. Grading of the tumors according to margins and heterogeneity is shown in Table 1. Results The demographic and imaging findings are summarized in Table 2. The tumor types included SPT in seven patients, pancreatoblastoma in two patients, and ductal adenocarcinoma in one patient. Tumor sizes (greatest diameter) ranged between 2 and 12 cm. The tumor was localized to the pancreatic head in seven patients, body in one patient, and tail in two patients. 662 JR:203, September 2014

2 Pancreatic Tumors in hildren TLE 1: Tumor Grading ccording to Margins and Heterogeneity Grade haracteristic Margins 1 Uniformly well-defined margins 2 > 50% of the margins well defined 3 < 50% of the margins well defined Heterogeneity 1 Homogeneous 2 Mildly heterogeneous 3 Very heterogeneous Solid Pseudopapillary Tumor Seven children (six girls, one boy; age range, 9 14 years) had SPT. ll seven patients underwent ultrasound, six underwent T, and four underwent MRI. Tumor sizes ranged between 2 and 10 cm. On ultrasound images, one tumor was homogeneous and solid in appearance (Fig. 1). The others were heterogeneous, composed of a mixture of cystic and solid components (Fig. 2). lthough color oppler imaging showed vascularity in five of seven cases, T images revealed contrast enhancement in six of six cases. On TLE 2: emographic and Imaging Findings Patient No. iagnosis ge (y) Sex Imaging Studies 1 SPT 14 F Ultrasound, T 2 SPT 11 F Ultrasound, T, MRI 3 SPT 12 F Ultrasound, T, MRI 4 SPT 9 F Ultrasound, T 5 SPT 11 M Ultrasound, T, MRI 6 SPT 12 F Ultrasound, T 7 SPT 12 F Ultrasound, MRI 8 Pancreatoblastoma 9 F Ultrasound, T, MRI 9 Pancreatoblastoma 2 F Ultrasound, T, MRI 10 uctal adenocarcinoma 9 F Ultrasound, T Note SPT = solid pseudopapillary tumor. T images, two tumors had slightly heterogeneous contrast enhancement, and four tumors had progressive peripheral enhancement (Figs. 1 and 2). In six patients, capsule was identified on ultrasound, T, and MR images, but gross pathologic and histologic findings showed that all tumors were encapsulated by a fibrous capsule. apsule was seen as an echogenic rim on ultrasound, hypoattenuation on T, and a peripheral hypointense rim on T1- and T2-weighted MR images. On MR images, three tumors had decreased signal intensity on T1-weighted images, increased signal intensity on T2-weighted images, and heterogeneous enhancement on contrast-enhanced T1-weighted images (Figs. 1 and 2). In one tumor, an area of increased signal intensity within the mass on T1-weighted images suggested hemorrhage (Fig. 2E). fter gadolinium administration, two tumors had peripheral enhancement similar to that on T images. isplacement of the surrounding vascular structures was found in two patients. iliary and pancreatic ductal dilatation, calcifications, and liver metastases were not identified in any tumor. ll four tumors localized in the head of the pancreas were resected, and the other tumors were removed in distal pancreatectomy. No recurrence was found during follow-up. Location Tumor Margin Grade Tumor Heterogeneity Grade apsule Present Pancreatoblastoma Two girls had pancreatoblastoma. In the first patient (age, 9 years 4 months) the tumor was in the pancreatic head. T showed no calcification. Vascular encasement of the celiac trunk and the splenic arteries was identified. The tumor had areas of increased T1 signal intensity secondary to hemorrhage and increased T2 signal intensity secondary to necrosis (Fig. 3). fter contrast administration, solid components exhibited marked enhancement. Hepatic metastatic lesions were detected on both T and MR images. The serum α-fetoprotein (FP) level was 0.81 ng/ml (normal, 0 9 ng/ml). The patient was treated with chemotherapy and continued to receive chemotherapy after the study period. The tumor in the second patient (age, 2 years 2 months) was in the pancreatic head. There were calcifications in the tumor (Fig. 4). The tumor had intermediate signal intensity on T1-weighted and increased signal intensity on T2-weighted images (Fig. 4). fter contrast administration, solid components had marked enhancement (Fig. 4). Pancreatic duct dilatation and vascular displacement of the surrounding vascular structures also were present. The serum FP level was elevated (13.9 ng/ml). The tumor was alcification Present iliary or Pancreatic uctal ilatation Vascular isplacement or Encasement Liver Metastasis Present Tail 1 2 Yes No No No No ody 1 1 No No No No No Head 2 3 Yes No No Yes (displacement) No Tail 1 2 Yes No No Yes No (displacement) Head 1 2 Yes No No No No Head 1 2 Yes No No No No Head 1 2 Yes No No No No Head 2 3 No No No Yes (encasement) Head 2 3 No Yes Yes Yes (displacement) Head 3 3 No No Yes Yes (encasement) Yes No Yes JR:203, September

3 Ozcan et al. E Fig year-old boy with solid pseudopapillary tumor of pancreas., Transverse sonogram shows well-circumscribed heterogeneous solid mass (arrows)., xial contrast-enhanced T scan shows well-circumscribed heterogeneous mass in head of pancreas with enhancement of solid components (arrow) and capsule (arrowhead)., xial T2-weighted MR image shows heterogeneous hyperintense mass (arrows) in head of pancreas., xial T1-weighted out-of-phase MR image shows heterogeneous hypointense mass (arrows) in head of pancreas. E, xial gadolinium-enhanced T1-weighted MR image shows predominant enhancement of capsule (arrows) and enhancement of solid portions. Fig year-old girl with solid pseudopapillary tumor of pancreas., Transverse sonogram of upper abdomen shows well-circumscribed heterogeneous mass (arrows) with solid and cystic components., xial contrast-enhanced T scan shows well-demarcated heterogeneously enhancing tumor (arrows) arising from head of pancreas. and, xial () and coronal () T2-weighted MR images show heterogeneous hyperintense mass in head of pancreas. Hypointense capsule (arrows) is evident. E, xial T1-weighted MR image shows hypointense capsule (arrows) and hyperintensity (asterisk) consistent with hemorrhage. F, xial contrast-enhanced fat suppression T1-weighted MR image shows predominant enhancement of capsule of mass (arrows) and enhancement of solid components. E F 664 JR:203, September 2014

4 Pancreatic Tumors in hildren Fig. 3 9-year-old girl with pancreatoblastoma., oronal T2-weighted MR image shows heterogeneous mass (arrows) in head of pancreas with hyperintense cystic areas., xial T2-weighted image shows liver metastasis (arrow)., xial T1-weighted image shows large, heterogeneous mass (arrows) with solid and cystic components. Presence of hyperintense areas (asterisk) suggests hemorrhage., xial contrast-enhanced T1-weighted image shows enhancement of solid components of mass (arrows). E resected, and recurrence was not found at follow-up evaluations. oth of the tumors had partially well-defined margins (grade 2), and tumors were very heterogeneous (grade 3). uctal denocarcinoma Only one patient in this series had ductal adenocarcinoma. The tumor was located in the head of the pancreas. olor oppler images showed no significant flow in the mass. T examination showed necrosis without any overt calcifications. The tumor was hypoattenuating in relation to the adjacent enhanced vessels and encased the celiac trunk and the superior mesenteric artery (Fig. 5). Multiple enlarged, peripherally enhancing lymph nodes up to 4 cm in diameter were adjacent to the pancreas, and intraabdominal free fluid was found. Multiple liver metastatic lesions and intrahepatic or extrahepatic biliary duct dilatation were seen. The patient died 3 years after the diagnosis. iscussion Pancreatic neoplasms are rare in childhood and have a different histologic spectrum and better clinical outcome than in adulthood [2]. Much more has been reported from the clinical and surgical perspectives and less about imaging findings [3 6]. Fig. 4 2-year-old girl with pancreatoblastoma., Transverse sonogram of upper abdomen shows heterogeneous mass with lobulate margins and hypoechoic cystic structures with hyperechoic internal septa and solid components (arrows)., xial contrast-enhanced T scan shows large, heterogeneous mass with peripheral septal enhancement. Round, nonenhancing cystic areas, intense enhancement of solid component (white arrow), and calcification (black arrow) are present within mass., xial contrast-enhanced T scan shows peripheral calcifications within mass (arrows)., oronal T2-weighted image shows heterogeneous hyperintense lobulate mass in head of pancreas with hypointense solid component (arrow). E, xial contrast-enhanced T1-weighted image shows enhancement of solid component of mass (asterisk). Septal enhancement (arrow) also is evident. JR:203, September

5 Ozcan et al. s in previous series [3 6], our results have shown that the most frequently detected pediatric pancreatic tumor is SPT. The term solid pseudopapillary tumor was adopted in the World Health Organization tumor classification in efore that, different names, such as papillary solid neoplasm, solid and papillary epithelial neoplasm, papillary cystic epithelial neoplasm, and Frantz tumor (Frantz first described the tumor in 1959 [7]) were used. Most SPTs are found in adolescent girls and young women, usually in the 2nd decade of life [10 12]. Typical ultrasound and T findings include a large, well-circumscribed solid lesion with variable amounts of cystic area corresponding to hemorrhagic necrosis [8]. The capsule may be visualized as an echogenic or, less commonly, hypoechoic rim at ultrasound. t T, the capsule is typically hypoattenuating, and at MRI it is seen as a peripheral hypointense rim on both T1- and T2-weighted images. antisani et al. [13] described early peripheral or slightly heterogeneous contrast enhancement of SPTs on gadolinium-enhanced MR images. They also observed that in seven of 10 patients, capsular enhancement appeared earlier and was more intense than tumor enhancement. alcifications were uncommon, but they may be seen in as many as one third of cases, usually in the periphery of the tumor [2]. alcifications can also be seen in mucinous cystic neoplasms and serous cystadenomas, so this condition does not appear to be a useful diagnostic feature. Our series included a highly unusual case of SPT in a boy. In addition, all tumors were detected in the 1st decade of life. Our findings suggest that most of these tumors are Fig. 5 9-year-old girl with ductal adenocarcinoma of pancreas., xial contrast-enhanced T scan shows hypoattenuating mass (arrowheads) arising in head of pancreas. Liver metastatic lesions (arrows) also are evident., oronal reformatted T image shows irregular mass in region of pancreatic head (arrowheads) and downward displacement of duodenum (arrows)., oronal reformatted T image shows dilatation of common bile duct (arrows). well defined. Six of seven tumors in our series had imaging evidence of cystic components, and only one had intratumoral hemorrhage of increased signal intensity on T1-weighted images. Six tumors in SPT patients had a capsule. Tumor calcifications were not found in our series. In four patients, the tumor had peripheral contrast enhancement on both T and MR images. SPT should be considered when a well-marginated, large, encapsulated, solid and cystic mass with progressive peripheral or slightly heterogeneous contrast enhancement is detected in the pancreas of a young woman. Pancreatoblastoma is a rare pancreatic tumor in children ( % of all pancreatic tumors) [14]. Pancreatoblastoma most commonly occurs in the 1st decade of life, and serum FP levels are often elevated in these patients [14]. The mean age at presentation is 4 years, although rare cases in adults have been reported [15, 16]. These tumors were described as typically large, well-defined, multilobulate masses with enhancing septa at T and as being heterogeneous masses with solid and cystic components [9, 17, 18]. MRI shows low to intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted images. Unlike those described in previous reports, a tumor in one of our patients had high signal intensity on T1-weighted images consistent with intratumoral hemorrhage. alcifications may be seen as small, punctate, clustered, or rimlike. Small calcifications were present in one of our two patients with pancreatoblastoma. iliary and pancreatic ductal dilatation may also be seen [16]. Lobulations, considered characteristic of this tumor, were seen in our patients. ompared with SPT, pancreatoblastoma is more heterogeneous and has larger dimensions, as in our patients. ecause of the large size of the tumor, it can be difficult to determine the organ of origin. The liver is the most common site of metastatic disease. Pancreatoblastoma is more aggressive than SPT. uctal adenocarcinoma is most commonly seen in adults; it is extremely rare among persons younger than 40 years. The clinical, imaging, and pathologic findings are similar to those in older adults [19, 20]. uctal adenocarcinoma is small, echogenic, and inhomogeneous at ultrasound examination, hypoattenuating at T, hypointense to normal pancreas on T1-weighted images owing to sclerosis, and variable in signal intensity on T2-weighted images [2]. uctal adenocarcinoma is most commonly seen as a small hypovascular mass in the head of the pancreas, often associated with dilatation of the main pancreatic duct and the common bile duct proximal to the mass [12]. Ivy et al. [19] reported poorer differentiation and high prevalence of metastatic disease among younger patients with ductal adenocarcinoma. The prognosis is as poor in younger patients as it is in older patients, the 5-year survival rate being 2 4% [19]. onclusion The most common primary pancreatic tumor of childhood is SPT, followed by pancreatoblastoma. SPTs are usually well marginated and encapsulated, have solid and cystic areas, exhibit peripheral or heterogeneous contrast enhancement, are cured by complete resection, and have an excellent 666 JR:203, September 2014

6 Pancreatic Tumors in hildren prognosis. Pancreatoblastoma is typically a heterogeneous tumor with lobulate margins and can behave aggressively by encasement of localized vascular structures and widespread metastasis. uctal adenocarcinomas more often present with distant metastases and have a worse prognosis than the other two tumors. References 1. Jaffe R. The pancreas. In: Stocker J, ehner L, eds. Pediatric pathology, 2nd ed. Philadelphia, P: Lippincott Williams & Wilkins, 2002: hung EM, Travis M, onran RM. Pancreatic tumors in children: radiologic-pathologic correlation. RadioGraphics 2006; 26: Rojas Y, Warneke L, hamne, et al. Primary malignant pancreatic neoplasms in children and adolescents: a 20 year experience. J Pediatr Surg 2012; 47: Jaksic T, Yaman M, Thorner P, et al. 20 year review of pediatric pancreatic tumors. J Pediatr Surg 1992; 27: Yu, Kozakewich HP, Perez-tayde R, Shamberger R, Weldon. hildhood pancreatic tumors: a single institution experience. J Pediatr Surg 2009; 44: Shorter N, Glick R, Klimstra S, rennan MF, LaQuaglia MP. Malignant pancreatic tumors in childhood and adolescence: the Memorial Sloan-Kettering experience, 1967 to present. J Pediatr Surg 2002; 37: Rebhandl W, Felberbauer FX, Puig S, et al. Solidpseudopapillary tumor of the pancreas (Frantz tumor) in children: report of four cases and review of the literature. J Surg Oncol 2001; 76: Nijs E, allahon MJ, Taylor G. isorders of the pediatric pancreas: imaging features. Pediatr Radiol 2005; 35: hmed TS, havhan G, Navarro OM, Traubici J. Imaging features of pancreatic tumors in children: 13-year experience at a pediatric tertiary hospital. Pediatr Radiol 2013; 43: oleman KM, oherty M, igler S. Solid pseudopapillary tumor of the pancreas. Radio- Graphics 2003; 23: Zhou H, heng W, Lam KY, han G, Khong PL, Tam PK. Solid-cystic papillary tumor of the pancreas in children. Pediatr Surg Int 2001; 17: Papavramidis T, Papavramidis S. Solid pseudopapillary tumors of the pancreas: review of 718 patients reported in English literature. J m oll Surg 2005; 200: antisani V, Mortele KJ, Levy, et al. MR imaging features of solid pseudopapillary tumor of the pancreas in adult and pediatric patients. JR 2003; 181: Saif MW. Pancreatoblastoma. JOP 2007; 8: Klimstra S, Wenig M, dair F, Heffess S. Pancreatoblastoma: a clinicopathologic study and review of the literature. m J Surg Pathol 1995; 19: Montemarano H, Lonergan GJ, ulas I, Selby M. Pancreatoblastoma: imaging findings in 10 patients and review of the literature. Radiology 2000; 214: Roebuck J, Yuen MK, Wong Y, et al. Imaging features of pancreatoblastoma. Pediatr Radiol 2001; 31: Lee JY, Kim IO, Kim WS, Kim W, Yeon KM. T and US findings of pancreatoblastoma. J omput ssist Tomogr 1996; 20: Ivy EJ, Sarr MG, Reiman HM. Nonendocrine cancer of the pancreas in patients under age forty years. Surgery 1990; 108: Lüttges J, Stigge, Pacena M, Klöppel G. Rare ductal adenocarcinoma of the pancreas in patients younger than age 40 years. ancer 2004; 100: FOR YOUR INFORMTION The comprehensive book based on the RRS 2014 annual meeting categorical course on The Radiology M and M Meeting: Misinterpretations, Misses, and Mimics is now available! For more information or to purchase a copy, see JR:203, September