Solid pseudopapillary neoplasm-diagnostic approach and post-surgical follow up: Three case reports and review of literature

Abstract

BACKGROUND Solid pseudopapillary neoplasm (SPN) is a rare tumor that was first described by Frantz in 1959. Although this tumor is benign, some may have malignant potential that can be predicted based on demographics, imaging characteristics, and pathologic evaluation. This case series presents 3 SPN cases with discussion on gender differences, preoperative predictors of malignancy, and a suggested algorithm for diagnostic approach as well as post-surgical follow up. CASE SUMMARY Three adult patients in a tertiary hospital found to have SPN, one elderly male and two young females. Each of the cases presented with abdominal pain and were discovered incidentally. Two cases underwent endoscopic ultrasound with fine needle aspiration and biopsy to assess tumor markers and immuno-histochemical staining (which were consistent with SPN before undergoing surgery), and one case underwent surgery directly after imaging. The average tumor size was 5 cm. Diagnosis was confirmed by histology. Two patients had post-surgical complications requiring intervention. CONCLUSION Demographic and imaging characteristics can be sufficient to establish diagnosis for SPN, while malignant cases require pre-operative evaluation with endoscopic ultrasound fine needle aspiration/fine needle biopsy.

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

“…Some researchers also found that the tumor size for cases with metastases was larger than that of nonmetastatic tumors (8.13 ± 1.03 cm for metastatic tumors and 5.20 ± 3.78 cm for nonmetastatic, range 7-9 cm, P < 0.012). Larger tumor size was significantly associated with the risk of metastasis and recurrence (P < 0.002) (46). The tumor resected from our patient was approximately 20 cm × 20 cm in size, and the postoperative pathological finding of the Ki-67 index was approximately 20%, so we speculated that these clinical features of the patient were one of the possible reasons for the recurrence.…”

“…Imaging examinations play an important role in the initial diagnosis of SPN, among which the most commonly used imaging modalities are ultrasound, CT, and magnetic resonance imaging (MRI) (17,46). The ultrasound features of SPN are mainly cystic and solid masses with heterogeneous internal echoes.…”

“…Most tumors were positive for CD99, α1-antitrypsin, NSE, P504s, and PR; some were positive for synaptophysin. However, they usually do not express chromogranin A or E-cadherin (3,46). Based on these typical features, the diagnosis of SPN can be performed.…”

“…Although the liver is the most common site of distant metastases, the mesentery, mentum, peritoneum, and lungs may also be involved. However, metastasis or invasion of adjacent organs is not a contraindication to surgery, and the patients could also have a longer survival time after reoperation (46). In addition to surgery, conventional adjuvant treatments can also be used for the treatment of SPN, such as hyperthermic intraperitoneal chemotherapy (HIPEC), radiofrequency ablation (RFA), transcatheter arterial embolization, radiotherapy, and chemotherapy (19).…”