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Gastrointestinal Imaging

E1183. Solid Pseudopapillary Tumor: What a Surgeon Wants to Know

Sharma P,  Kochar P,  Sulaiman R,  Ghasemiesfe A,  Kumar Y. Yale New Haven Health System at Bridgeport Hospital,, Bridgeport, CT

Address correspondence to P. Sharma (drpranavsharma29@gmail.com)

Background Information: We describe a series of four cases of incidentally detected cystic pancreatic neoplasms with their histopathologic correlation. The multimodality imaging approach has been used in characterizing these lesions. Solid and papillary epithelial neoplasm and solid pseudopapillary tumor (SPT) are rare, accounting 1-2% of exocrine pancreatic tumors with low malignant potential, presenting asymptomatically or with vague abdominal pain in young women around second and third decades of life, with excellent prognosis after resection.

Educational Goals/Teaching Points: In this exhibit, we review the presentation, clinical picture, imaging features, differentiation between benign and malignant tumors, and how to communicate the appropriate information to the surgical team. Surgeons have a different terminology in relation to the pancreas and need some specific information in the reports.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: SPT occurs in the young female African-American population (10–50 years of age), having cystic and papillary components with hemorrhage and fluid-fluid levels. Patients with SPT of the pancreas are generally asymptomatic and may present with vague abdominal pain or a gradually increasing mass. Clinically, the abdomen is generally not tender to palpation but sometimes they present with features of obstruction. The laboratory findings including the pancreatic cell cancer markers like carbohydrate antigen 19-9 and carcinoembryonic antigen are usually normal. Tumor markers like Ki-67 have relation to malignant potential. These tumors are predominantly located in the tail or head, are well marinated, and can have peripheral calcification. These lesions lack communication with the pancreatic duct, thereby differentiating it from intraductal papillary mucinous neoplasms. When incidentally detected on an abdominal ultrasound or abdominal CT scan, the primary workup includes pancreatic protocol CT or MRI. If the imaging findings show very small peripheral cysts, then follow-up at close intervals is performed. Various criteria have been described in the literature for differentiating benign versus malignant changes, like a cystic lesion involving the main pancreatic duct, marked dilatation of the main pancreatic duct, enlargement with nodules or septal thickening or irregularity, and size more than 3 cm. In cases of indeterminate or suspicious findings, further workup with endoscopy ultrasound and biopsy is performed. In case of malignant findings, the surgical treatment is the mainstay. Surgeons use a different terminology in contrast to radiologists, like for lesions in the tail of pancreas, the treatment is distal pancreatectomy with splenectomy; however, radiologically speaking, the tail is the proximal pancreas. Hence, the terminology in the reports must be more descriptive rather than tumor in the proximal or distal pancreas. For example, a mass in the body of pancreas causes dilatation of pancreatic duct proximally, i.e., in the tail. Hence, the description of the lesion should be with the site, i.e., head, uncinated, neck, body, or tail. Surgeons also want to know if there is any involvement of adjacent vessels like superior mesenteric vessels or any organ invasion or lymphadenopathy. Generally, the prognosis of SPT is good, even with recurrence and metastasis, with an overall 5-year survival rate of 95%.

Conclusion: The differential diagnosis for a cystic lesion in the pancreas is wide and are indistinguishable on clinical and historical characteristics; however, some imaging criteria help to make a suggestive diagnosis that needs to be confirmed with histopathologic correlation. Thus, identifying the imaging characteristics and differentiating benign versus malignant are important. The findings need to be clearly communicated to the treatment team for adequate treatment and follow-up.