Institutional Experience With Solid Pseudopapillary Neoplasms

Abstract

Objective Solid pseudopapillary neoplasms (SPNs) are low-grade malignancies with an excellent prognosis, albeit with the potential for metastatic disease. This study details our institution's experience with the diagnosis and treatment of SPN, including clinical presentation, multimodality imaging findings, and potential predictors of aggressive tumor behavior. Materials and Methods The institutional pathology database was searched through for all cases of SPN since 1988, yielding 51 patients. The electronic medical record was searched for clinical and demographic information regarding these patients, including age, sex, presenting symptoms, type of surgery, postoperative length of stay, tumor markers, and postsurgical follow-up. All available imaging data were reviewed, including those of 30 patients who underwent multidetector computed tomography, those of 9 patients who underwent magnetic resonance imaging (MRI), those of 3 patients who underwent conventional ultrasound, and those of 11 patients who underwent endoscopic ultrasound. Results A total of 84% of patients were females, with a mean age of only 33 years. Prognosis was excellent, with a mean follow-up of 3 years without recurrence. Only 1 of the 51 patients developed metastatic disease to the liver 8 years after the surgery. On computed tomography, lesions tended to be large (5.3 cm), well circumscribed (29/30), round/oval (20/30), and encapsulated (23/30). The lesions often demonstrated calcification (14/30) and typically resulted in no biliary or pancreatic ductal dilatation. The lesions ranged from completely cystic to completely solid. On MRI, the lesions often demonstrated a T2 hypointense or enhancing capsule (6/9) and demonstrated internal blood products (5/9). The lesions tended to be devoid of vascularity on conventional ultrasound. Ten patients were found to have “aggressive” histology at presentation (T3 tumor, nodal involvement, perineural invasion, or vascular invasion). No demographic, clinical, or multidetector computed tomographic imaging features were found to correlate with aggressive histology. Conclusions Certain imaging features (eg, well-circumscribed mass with calcification, peripheral capsule, internal blood products, and lack of biliary/pancreatic ductal obstruction) on computed tomography and MRI are highly suggestive of the diagnosis of SPN, particularly when visualized in young female patients. However, it is not possible to predict aggressive histology on the basis of imaging findings, clinical presentation, or patient demographic features.

Risk Factors of the Recurrences of Pancreatic Solid Pseudopapillary Tumors: A Systematic Review and Meta-analysis

“…Owing to the covert manifestations, pancreatic SPTs are usually picked up by imaging examinations 28 . Typical imaging characteristics of pancreatic SPTs are described as encapsulated masses with solid and cystic components and frequent internal hemorrhage 29 . Although SPTs have typical radiological features, some of them were still preoperatively misdiagnosed for pancreatic cystic neoplasms 23 .…”

Prediction of malignancy and adverse outcome of solid pseudopapillary tumor of the pancreas

“…Yu et al[ 31 ] and Xu et al[ 35 ] showed that positive status for Ki-67 correlated with malignancy of SPTP, while Yang et al[ 8 ] did not demonstrate any association between the Ki-67 index and malignant SPTP. Most other studies[ 20 , 23 , 26 , 27 , 57 , 58 ] found no significant differences between benign and malignant SPTP, including age, sex, symptomatology, laboratory data, tumor marker, tumor size and location, tumor composition, growth pattern, and histopathology. Thus, malignancy cannot be easily predicted on the basis of preoperative findings and immunohistochemical patterns.…”

“…Due to the arbitrary criteria of malignancy used, and rarity of the disease with small proportion of malignancy, conflicting results have been reported about factors associated with malignant potential across institutions[ 8 , 20 , 23 , 24 , 26 , 27 , 30 , 31 , 35 , 36 , 38 , 39 , 56 - 58 ] (Figure 4 ). Butte et al[ 24 ] found that patients with malignant SPTP presented with larger tumor size ( P < 0.005).…”

Solid Pseudopapillary Neoplasm of the Pancreas: Analysis of Seven Cases

“…Despite the large size of these tumors, vascular encasement or occlusion is quite rare (13%), although the large size of the masses sometimes leads to considerable displacement of the adjacent vasculature. MRI is superior to CT in distinguishing certain tissue characteristics, such as hemorrhage, cystic degeneration, or the presence of a capsule, and may enable correct diagnosis [ 16 ]. CT scans might help to diagnose SPNs accurately in 80% of the cases [ 17 ].…”