Eur. Radiol. 6, 86-88 (1996) © Springer-Verlag 1996

European Radiology

Abdominal radiology Solid and papillary epithelial neoplasm of the pancreas: CT and MR findings G. Savci, S. Kilicturgay, Z. Sivri, M. Parlak, E.Tuncel Department of Radiology,Uludag University Medical School, Gorukle Campus, %16059 Gorukle, Bursa, Turkey Received 21 November 1994; Revision received 4 April 1995; Accepted 3 May 1995 veloped leads to cure [1-5]. We present a case of solid and papillary epithelial neoplasm of the pancreas due to its rare occurrence.

Case report

Introduction Solid and papillary epithelial neoplasm of the pancreas is a rare low-grade malignant tumor occurring in the second to third decades of life chiefly in female patients (especially in black female patients) [1-5]. Several synonyms have been used for this tumor including papillary epithelial neoplasm and solid and cystic acinar-cell tumor. Approximately 126 cases have been reported to date, some under the names of papillary and epithelial neoplasm, papillary and cystic neoplasm, or papillarycystic carcinoma. In Japan the term "solid and cystic tumor" has recently been preferred, because tumor origin has been suggested to be from multipotential primordial cells rather than acinar cells [1]. Preoperative recognition is important, because excision of this tumor before malignant transformation deCorrespondence to: G. Savci

An otherwise healthy, 20-year-old female who was being followed for 8 months for a cystic mass located in the tail of the pancreas with a preliminary diagnosis of pancreatic hydatid disease was referred to our hospital for further investigation. There had been no change in the follow-up CT examination undertaken 6 months later (Fig. 1). Her laboratory tests were unremarkable. The mass was 4 cm in diameter and had soft tissue density (42 HU), capsule formation, some internal septations, and curvilinear calcifications. Upon abdominal M R examination the mass had some high intensity areas on T l W images (Fig. 2 a) that was more obvious on gradient-recalled echo (GRE) images (Fig. 2b). On T2W images the mass consisted of heterogeneous internal content with mainly hypointense signals. Calcific areas were seen as signal void. With these findings solid and papillary epithelial neoplasm of the pancreas was suggested and surgery was referred. The mass had clear margins and neither vascular invasion nor lymph node nor liver metastasis were detected. Distal pancreatectomy including the mass and splenectomy was performed. Pathological examination showed low-grade atypical cells and internal hemorrhagic regions. Upon a postoperative ll-month followup period, no laboratory, clinical or radiological abnormalities were detected.

Discussion Cystic pancreatic neoplasms are rare tumors accounting for only 10-15 % of all pancreatic cysts and fewer than 5 % of pancreatic tumors. They exhibit a wide spectrum of biological behavior, from being completely benign to

G. Savci et al.: Solid and papillary epithelial neoplasm of the pancreas

Fig. 1. Contrast-enhanced CT of the solid and papillary epithelial neoplasm of the pancreas showing its typical location, cystic appearance, capsule formation, and peripheral calcification Fig.2a, b. a Tl-weighted spin-echo MR (500/15); I~Breathhold Tl-weighted gradient-recalled echo (GRE) flash MR images (100/6/70 °) of the same mass with internal hyperintense signals secondary to hemorrhage and hypointense capsule formation. Note that hyperintense signals are more obvious on GRE image

87 aggressively malignant. They include serous (glycogenrich or "microcystic") and mucinous ("macrocystic") tumors, solid and papillary epithelial tumors, mucinous ductal ectasia (MDE), and, rarely, islet cell tumors and adenocarcinoma. While serous lesions are considered to be uniformly benign, islet cell tumors and M D E may be benign or malignant, and adenocarcinoma is always malignant [6, 7]. Solid and papillary epithelial neoplasms are low-grade malignant tumors that, without treatment, malignant transformation may be possible [1-5]. Of the cases 95 % are seen in females and 85 % are present by age 30 years [5], and mean age at presentation is 22 years, [2] similar to our case. This tumor has been demonstrated to contain receptors for estrogen and progesterone explaining the age and gender distribution [5]. Most patients present with signs and symptoms of an abdominal mass with a mean size of 12 cm [5]. The mass in our case was considerably smaller than this size and did not have any symptom attributable to its mass effect indicating the early diagnosis. Pathologically, all tumors show intratumoral hemorrhage followed by varying size of cystic degeneration and large cystic area in CT scans corresponded to extensive cystic necrosis filled with coagulum and necrotic tumor tissue [3]. Microscopically, solid areas of cystic spaces, loci of hemorrhage, and areas of a definite papillary arrangement are found [2]. Pathological misdiagnosis as nonfunctional islet cell tumor, cystadenocarcinoma or cystadenoma is fairly common [4]. The presence of direct extension to the pancreas and peripancreatic regions, multinucleated giant cells, mitoses and bizarre cells have been considered to be malignant signs in addition to venous invasion [8]. Because the mass had capsule formation and neither peripancreatic nor venous invasion were detected, early detection and treatment in our case lead to cure despite some lowgrade atypical cells that were detected on pathological examination. These low-grade malignant tumors may have variable appearances on CT scans. These tumors are most commonly located in the pancreatic tail [1, 5, 6] as in our case. On CT scans all reported cases appear well marginated and nonhomogeneous due to variable internal architecture most commonly seen as a mixture of solid and cystic components [1-6]. The CT numbers of the cystic areas are higher than water and ranged from 40 to 50 H U [3, 5] a finding secondary to intratumoral hemorrhage. This indirectly suggestive finding may be used to distinguish papillary cystic tumor from serous neoplasms of the pancreas that have much lower density. Calcification is an infrequent finding [1, 3-5]. In previous reports calcification has not been reported, and the presence of calcification was previously considered to increase the likelihood of other pancreatic tumors. However, recent reports have contradicted this finding, and if calcification is seen, it occurs in the periphery of the capsule as our case showed [3]. If the calcification has sunburst type and central location, it would favor se-

88 rous adenoma or islet cell tumors [7]. Calcification is more obvious on CT scans than on M R images [1]. The M R image can show the internal architecture of the masses better than CT [1]. Hyperintense areas on T l W images, representing the paramagnetic content of the lesion, corresponds to hemorrhagic necrosis in the solid or hemorrhagic debris in the cystic areas. On T2W images these areas have inhomogeneously low signals. This may be explained by the presence of paramagnetic metabolites of methemoglobin and hemosiderin. H e m orrhagic areas detected upon histopathological examination was responsible for both hyperintense signals on T l W images and hyperdense areas on CT scans in the center of the mass. The M R image can also show capsule formation better than CT. A capsule is seen in two thirds of cases. In addition to the intratumoral hemorrhage, demonstration of a low-intensity signal around the mass might be another characteristic feature of solid and papillary neoplasm [1]. In our case both capsule formation and intratumoral hyperintense signals led to correct diagnosis. Differential diagnosis of solid and papillary epithelial neoplasms includes serous cystadenoma, mucinous cystic neoplasms, nonhyperfunctioning islet cell tumors, and pancreatoblastomas [1, 3-5, 7]. Clinically, the former three tumors rarely occur in patients younger than 30 years of age. Serous cystadenoma is composed of innumerable cysts smaller than 2 cm in diameter, and diagnosis is easy when a so-called honeycomb appearance is seen. Sometimes, light microscopic differentiation from islet cell neoplasms may be difficult. Both CT and M R can be useful in the diagnosis of solid and papillary epithelial tumors. The M R image can show the intratumoral hemorrhage and peritumoral

G. Savci et al.: Solid and papillary epithelial neoplasm of the pancreas capsule formation better than CT, but calcification is more obvious on CT scans. There may still be some overlapping between CT and M R findings of solid and papillary neoplasm and the other cystic pancreatic neoplasms. When M R shows intratumoral hemorrhage surrounded by fibrous capsule, solid and papillary epithelial neoplasm is the first consideration especially in a young female [1]. This is a very important point, because excision at early stage means cure, and delay may lead to malignant transformation.

References 1. Ohtomo K, Furui S, Onoue M, Okada Y, Kusano S, Shiga J, Suda K (1992) Solid and papillary epithelial neoplasm of the pancreas: MR imaging and pathologic correlation. Radiology 184:567-570 2. Morrison DM, Jewell LD, McCaughey TE, Danyluk J, Shnitka TK, Manickavel V (1984) Papillary cystic tumor of the pancreas. Arch Pathol Lab Med 108:723-727 3. Choi BI, Kim KW, Han MC, Kim YI, Kim C (1988) Solid and papillary epithelial neoplasm of the pancreas: CT findings. Radiology 166:413-416 4. Friedman AC, Lichtenstein JE, Fishman EK, Oertel JE, Dachman AH, Siegelman SS (1985) Solid and papillary epithelial neoplasm of the pancreas. Radiology 154:333-337 5. Phillips GWL, Chou ST, Mulhauser J (1991) Papillary cystic tumour of the pancreas: findings at computed tomography and ultrasound. Br J Radiology 64:367-369 6. Mathieu D, Guigui B, Valette PJ et al. (1989) Pancreatic cystic neoplasms. Radiol Clin North Am 27:163-176 7. Itai Y, Ohhashi K, Furui S, Araki T, Murakami Y, Ohtomo K, Atomi Y (1988) Microcystic adenoma of the pancreas: spectrum of computed tomographic findings. J Comput Assist Tomogr 12:797-803 8. Nishihara K, Nagoshi M, Tsuneyoshi M, Yamaguchi K, Hayashi I (1993) Papillary cystic tumor of the pancreas. Cancer 71:82-92