CASE 15675 Published on 29.04.2018

Teaching Case

Section

Abdominal imaging

Case Type

Clinical Cases

Authors

Rita Camelo, João Lopes Dias

Hospital de Sao José,
Centro Hospitalar Lisboa Central,
Radiologia;
Rua José António Serrano
1150-199 Lisboa, Portugal;
Email:ritameiracamelo@gmail.com

Patient

28 years, female

Categories

Area of Interest Abdomen, Pancreas ; Imaging Technique MR-Diffusion/Perfusion, MR ;

Procedure Education ; Special Focus Neoplasia ;

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Clinical History

A 28-year-old woman came to the hospital complaining of severe lumbar discomfort and abdominal fullness during the last months. On physical examination, an epigastric mass was palpable. There were no previous abdominal surgery or significant medical history. Blood tests were unremarkable. After an initial ultrasonography, she was referred for MRI.

Differential Diagnosis List

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Solid pseudopapillary tumour of the pancreas.

Gastrointestinal stromal tumour

Pancreatic endocrine neoplasm

Imaging Findings

MRI showed an 11-cm solid, round, well-defined, heterogeneous tumour, arising from the head of the pancreas, between Wirsung and Santorini ducts, which were deviated, but not invaded or dilated. The tumour was hyperintense on T2-weighted imaging (T2WI) and hypointense on T1-weighted imaging (T1WI), showing restriction on diffusion-weighted imaging (DWI) and heterogeneous enhancement, with solid progressive enhancing content and some cystic non-enhancing areas. The anatomopathological examination after resection revealed a solid pseudopapillary pancreas tumour.
A 2.3-cm lesion was also demonstrated at segment VI of the liver, apparently encapsulated, slightly hyperintense on T2WI and hypointense on T1WI, non-restrictive on DWI, with strong enhancement in the arterial phase and a late enhancing central scar. These findings are consistent with and characteristic for a focal nodular hyperplasia.

Discussion

Solid pseudopapillary tumour (SPT) of the pancreas is a very rare pathological condition, which represents less than 3% of all exocrine pancreatic tumours [1, 2]. More than 90% occurs in young women, with a median age of 20–30 years [2, 3].
The exact pathogenesis of this usually benign tumour remains unclear. Some authors postulated that it may arise from centroacinar cells located between pancreatic acini and ducts, while others say that it has an endocrine origin [4, 5, 6].
A constant apparent increase of its incidence has been noted over the past two decades, but this is probably due to improved imaging techniques and better recognition of the entity [7, 8].
There is a predilection for these tumours to be located in the distal body and tail of the pancreas. Moreover, in these locations, tumours have a tendency to be larger [9].
Imaging tools play an important role in the evaluation of this entity. Under the appropriate clinical context, MRI is highly likely to provide the correct diagnosis. SPTs usually present as heterogeneous masses, occasionally encapsulated, with areas of necrosis, haemorrhage, and cystic degeneration, although small SPTs may present as purely solid lesions [9]. Typically, SPTs have variable signal intensity on T1WI, high signal intensity on T2WI and a hypointense rim on both T1 and T2 WI. On post-gadolinium images, lesions generally demonstrate heterogeneous peripheral enhancement with progressive but incomplete enhancement during portal venous and equilibrium phases [10].
These are non-specific imaging findings that may lead to a broad differential diagnosis, including: pancreatic pseudocysts, pancreatic adenocarcinomas, mucinous cystic tumours, microcystic adenomas, islet cell tumours, and pancreaticoblastomas [11]. Huge SPTs may also be mistaken as extra-pancreatic, depending on tumour location. While pancreatic head tumours may suggest liver lesions, tail tumours may mimic a renal lesion.
Despite being usually benign, SPT may be considered malignant if it shows pancreatic parenchymal infiltration, perineural invasion, angio-invasion, increased mitotic rate, peripancreatic soft tissue invasion, capsular invasion, lymph node involvement, adjacent organ invasion or distant metastases [12, 13].
Total resection of the tumour is curative in more than 85% of patients. However, recurrence may occur in some cases, and a small percentage (less than 15%) of patients may develop metastases. The overall survival rate at 10 years from surgical resection was over 90% [2]. Our patient underwent a cephalic duodenopancreatectomy, with no early complications.

References

[1] Estrella JS, Li L, Rashid A, Wang H, Katz MH, Fleming JB, et al. (2004) Solid pseudopapillary neoplasm of the pancreas: clinicopathologic and survival analyses of 64 cases from a single institution. Am J Surg Pathol 38(2):147–157 (PMID: 24418850)

[2] Papavramidis T, Papavramidis S. (2005) Solid pseudopapillary tumors of the pancreas: review of 718 patients reported in English literature. J Am Coll Surg 200(6):965–972 (PMID: 15922212)

[3] Nishihara K, Nagoshi M, Tsuneyoshi M, Yamaguchi K, Hayashi I. (1993) Papillary cystic tumors of the pancreas. Assessment of their malignant potential. Cancer 71(1):82–92

[4] Chen X, Zhou GW, Zhou HJ, Peng CH, Li HW (2005) Diagnosis and treatment of solid-pseudopapillary tumors of the pancreas. Hepatobiliary Pancreat Dis Int 4(3):456-459 (PMID: 16109536)

[5] Bergmann F, Andrulis M, Hartwig W, Penzel R, Gaida MM, Herpel E, et al (2014) Discovered on gastrointestinal stromal tumor 1 (DOG1) is expressed in pancreatic centroacinar cells and in solid-pseudopapillary neoplasms--novel evidence for a histogenetic relationship. Hum Pathol 42(6):817–823 (PMID: 21295818)

[6] Hassan I, Celik I, Nies C, Zielke A, Gerdes B, Moll R, et al. (2005) Successful treatment of solid-pseudopapillary tumor of the pancreas with multiple liver metastases. Pancreatology 5(2–3):289–294 (PMID: 15855828)

[7] Alexandrescu DT, O’Boyle K, Feliz A, Fueg A, Wiernik PH (2005) Metastatic solid-pseudopapillary tumour of the pancreas: clinico-biological correlates and management. Clin Oncol 17(5):358–363 (PMID: 16097567)

[8] Spătaru RI, Enculescu A, Popoiu MC (2014) Gruber-Frantz tumor: a very rare pathological condition in children. Rom J Morphol Embryol 55(4):1497-501 (PMID: 25611288)

[9] Anil G, Zhang J, Al Hamar NE, Nga ME (2017) Diagn Interv Radiol. Solid pseudopapillary neoplasm of the pancreas: CT imaging features and radiologic-pathologic correlation 23(2):94-99 (PMID: 28089954)

[10] Sunkara S , Williams T R , Myers D T , Kryvenko O N (2012) Solid pseudopapillary tumours of the pancreas: spectrum of imaging findings with histopathological correlation. Br J Radiol 85(1019) (PMID: 22514105)

[11] Hamoudi AB, Misugi K, Grosfeld JL, Reiner CB (1970) Papillary epithelial neoplasm of pancreas in a child. Report of a case with electron microscopy. Cancer 26(5):1126-34 (PMID: 5476792)

[12] Wang XG, Ni QF, Fei JG, Zhong ZX, Yu PF (2013) Clinicopathologic features and surgical outcome of solid pseudopapillary tumor of the pancreas: analysis of 17 cases. World J Surg Oncol 11:38 (PMID: 23384084)

[13] Hwang J, Kim DY, Kim SC, Namgoong JM, Hong SM (2014) Solid-pseudopapillary neoplasm of the pancreas in children: can we predict malignancy?. J Pediatr Surg 49(12):1730–1733 (PMID: 25487471)

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