Radiologic Findings in Extrapancreatic Solid Pseudopapillary Tumor with Aggressive Behavior: a Case Report

PET/CT Findings of a Solid Pseudopapillary Tumor Mimicking Adrenocortical Carcinoma

Solid pseudopapillary tumor (SPT) is a rare low-grade malignant neoplasm originating predominantly in the pancreas. Extra-pancreatic SPTs are exceedingly rare clinical entities. The 18F-FDG PET/CT imaging features of extra-pancreatic SPTs remain poorly characterized in the current literature. We present a diagnostically challenging case of left adrenal SPT demonstrating MRI and 18F-FDG PET/CT features indistinguishable from adrenocortical carcinoma, ultimately resulting in preoperative misdiagnosis.

Malignant Solid Pseudopapillary Neoplasm of the Pancreas: An Orthogonal Analysis

BACKGROUND

Pancreatic solid pseudopapillary neoplasms (SPN) are generally indolent; however, some patients present with "malignant" SPN. An orthogonal analysis of multiple datasets was performed to investigate the utility of complete surgical resection (CSR) for malignant SPN.

METHODS

A systematic review was performed for cases of malignant SPN, defined as T4, N1, and/or M1. Malignant SPN was analyzed within the National Cancer Database (NCDB) and compared with T1-3N0M0 SPN. Predictors of malignant SPN were assessed, and treatments were analyzed by using survival analysis.

RESULTS

The systematic review yielded 164 cases of malignant SPN. Of 31 children, only one died due to malignant SPN. Among adults, CSR was associated with improved disease-specific survival (DSS) (P = 0.0002). Chemotherapy did not improve malignant SPN DSS, whether resected (P = 0.8485) or not (P = 0.2219). Of 692 adults with SPN within the NCDB, 93 (13.4%) had malignant SPN. Pancreatic head location (odds ratio [OR] 2.174; 95% confidence interval [CI] 1.136-4.166; P = 0.0186) and tumor size (OR 1.154; 95% CI 1.079-1.235; P < 0.0001) associated with the malignant phenotype. Malignant SPN predicted decreased overall survival (OS) compared with T1-3N0M0 disease (P < 0.0001). Resected malignant SPN demonstrated improved OS (P < 0.0001), including resected stage IV malignant SPN (P = 0.0003). Chemotherapy did not improve OS for malignant SPN, whether resected (P = 0.8633) or not (P = 0.5734). Within a multivariable model, resection was associated with decreased hazard of death (hazard ratio 0.090; 95% CI 0.030-0.261; P < 0.0001).

CONCLUSIONS

Approximately 13% of patients with SPN present with a malignant phenotype. Pediatric cases may be less aggressive. Resection may improve survival for malignant SPN, which does not appear chemosensitive.

Case report: A case report and literature review of extrapancreatic solid pseudopapillary neoplasm

Background

Solid pseudopapillary neoplasm (SPN) is a rare tumor with low malignant potential, which typically occurs in the pancreas. Extrapancreatic SPN is also extremely rare worldwide.

Case presentation

We report a case of a 70-year-old woman hospitalized with abdominal pain and bloating. The patient did not have any underlying diseases, such as diabetes, coronary heart disease, or hypertension. More than 30 years ago, the patient underwent surgery for “ectopic pregnancy”. The patient had no family history of hereditary disease, nor did any immediate family members have a history of cancer. Laboratory tests showed that her hemoglobin and albumin levels were low and she had a high level of cancer antigen 125 (CA125). Enhanced computed tomography (CT) showed a large tumor in the abdomen and pelvis. The patient subsequently underwent surgery, and it was found that the tumor was attached to the terminal ileum. Pathological findings suggested that the tumor was an extrapancreatic SPN, with an ectopic pancreas found in the tumor tissue. The patient did not receive chemotherapy or radiotherapy after surgery. After 13 months of follow-up, the patient was admitted again with abdominal pain. CT showed tumor recurrence with extensive systemic metastases. The patient and her family refused reoperation and biopsy, and the patient was discharged after the abdominal pain and anemia resolved.

Conclusion

We report a rare case of extrapancreatic SPN of ileal origin, which could be the first report worldwide. It had aggressive biological features, with recurrence and metastasis 13 months after surgery. For extrapancreatic SPN, the risk of recurrence should be assessed, and for tumors suspected of malignant behavior, a longer follow-up after discharge may be needed. Although SPN generally has a good prognosis after surgery, there is no consensus on whether postoperative chemotherapy and other treatments are needed for patients with high recurrence risk.