Unraveling the enigma:A comprehensive review of solid pseudopapillary tumor of the pancreas

Solid pseudopapillary tumor of the pancreas(SPTP)is a rare neoplasm predom-inantly observed in young females.Pathologically,CTNNB1 mutations,β-catenin nuclear accumulation,and subsequent Wnt-signaling pathway activation are the leading molecular features.Accurate preoperative diagnosis often relies on imaging techniques and endoscopic biopsies.Surgical resection remains the mainstay treatment.Risk models,such as the Fudan Prognostic Index,show promise as predictive tools for assessing the prognosis of SPTP.Establishing three types of metachronous liver metastasis can be beneficial in tailoring individu-alized treatment and follow-up strategies.Despite advancements,challenges persist in understanding its etiology,establishing standardized treatments for unresectable or metastatic diseases,and developing a widely recognized grading system.This comprehensive review aims to elucidate the enigma by consolidating current knowledge on the epidemiology,clinical presentation,pathology,molecular characteristics,diagnostic methods,treatment options,and prognostic factors.

Solid pseudopapillary tumor of the pancreas:A review of 553 cases in Chinese literature

AIM:To sum up the clinical and pathological characte- ristics of solid pseudopapillary tumor (SPT) and the experience with it.METHODS: A total of 553 SPT patients reported in Chinese literature between January 1996 and January 2009 were retrospectively reviewed and analyzed. RESULTS: The mean age of the 553 SPT patients included in this review was 27.2 years, and the male to female ratio was 1:8.37. Their symptoms were non-specific, and nearly one third of the patients were asymptomatic. Computed tomography and ultraso-nography were performed to show the nature and location of SPT. Most of the tumors were distributed in the pancreatic head (39.8%), tail (24.1%), body andtail (19.5%). Forty-five patients (9.2%) were diagnosed as malignant SPT with metastasis or invasion. None of the clinical factors was closely related to the malignant potential of SPT. Surgery was the main therapeutic modality for SPT. Local resection, distal pancreatectomy and pancreatoduodenectomy were the most common surgical procedures. Local recurrence and hepatic metastasis were found in 11 and 2 patients, respectively, after radical resection. Four patients died of tumor progression within 4 years after palliative resection of SPT. The prognosis of SPT patients was good with a 5-year survival rate of 96.9%.CONCLUSION: SPT of the pancreas is a rare indolent neoplasm that typically occurs in young females. It is a low-grade malignancy and can be cured with extended resection. The prognosis of such patients is good although the tumor may recur and metastasize.

Analysis of invasiveness and tumor-associated macrophages infiltration in solid pseudopapillary tumors of pancreas

BACKGROUND Solid pseudopapillary tumor(SPT)is a rare pancreatic tumor.Considering its malignant behaviors,SPT has been classified as a low-grade malignant tumor.Indeed,only 9.2%of all SPT patients are initially diagnosed as malignant with invasion or metastasis.Thus,one of the challenges in managing SPT patients is predicting malignant behavior.AIM To investigate the malignant behavior and tumor-associated macrophage(TAM)infiltration between different histopathologic features of SPT patients.METHODS Twenty-five formalin-fixed paraffin-embedded tissue samples from 22 patients pathologically diagnosed with an SPT between 2009 and 2019 at West China Hospital were included in this retrospective study.Integrity of the capsule and growth pattern of the tumor cells was assessed microscopically in hematoxylineosin(HE)-stained sections.Based on the histopathological features,the SPT patients were divided into two groups:capsule or invasion.Clinical features,malignant behavior,and TAM infiltration were compared between the two groups.RESULTS Among the 22 SPT patients,11 were identified for each group,having either a capsule or invasion histopathologic feature.Malignant behavior was more frequent in the invasion group,including 2 patients who had peripheral organ invasion,3 with liver metastasis,and 1 with both lymph node and spleen metastases(P=0.045).Ki-67 index of more than 3%was also more frequent in the invasion group(P=0.045).Immunohistochemical analysis showed that the invasion group had a significant increase of CD68-positive TAMs in intratumor and peritumor sites in comparison with the capsule group(all P<0.0001).Similarly,CD163-positive M2-like macrophages were also markedly increased in the intratumor and peritumor sites in the invasion group(all P<0.0001).At the liver metastasis site,both intratumor and peritumor tissues showed relatively high-level CD68-positive TAMs and CD163-positive M2-like macrophages infiltration.However,the differences between the intratumor,peritumor and normal hepatic tissues did not reach statistical significance(all P>0.05).CONCLUSION SPT patients with invasion evident under microscope were more likely to exhibit malignant behavior and TAM infiltration,especially M2-like macrophages.This finding can help in future investigations of the underlying mechanism of TAM-mediated SPT malignant behavior.

Retroperitoneal congenital epidermoid cyst misdiagnosed as a solid pseudopapillary tumor of the pancreas:A case report

BACKGROUND Retroperitoneal cysts are rare and usually asymptomatic abdominal lesions.Epidermoid cysts are frequent benign cutaneous tumors,but retroperitoneal localization of these cysts does not occur very often.CASE SUMMARY We report a case report of a 25-year-old woman with a giant mass in the abdominal cavity.Because imaging examination indicated that the mass probably originated from the pancreas,the mass was considered a solid pseudopapillary tumor of the pancreas(SPTP).However,surgery revealed a retroperitoneal epidermoid cyst located behind the pancreas neck and the root of the superior mesenteric artery(SMA).We performed complete resection of the tumor.Postoperative pathology showed an epidermoid cyst.The patient fared well after two months of follow-up.CONCLUSION Surgery is the gold standard for the diagnosis and treatment of retroperitoneal epidermoid cysts.Retroperitoneal epidermoid cysts around the pancreas are easily misdiagnosed as cystic SPTPs.Surgeons should pay particular attention to preoperative diagnosis to reduce severe surgical complications and improve the quality of life of patients.

Cryoablation for liver metastasis from solid pseudopapillary tumor of the pancreas: A case report

BACKGROUND Solid pseudopapillary tumor(SPT) of the pancreas is a rare pancreatic tumor and 10% to 15% of cases are associated with metastasis. Cryoablation is a new method that can induce tumor necrosis, and treatment of tumors by cryoablation can cause anti-tumor immune responses.CASE SUMMARY A 16-year-old woman with SPT of the pancreas developed liver metastases 5.3 years after complete resection of the primary pancreatic tumor. She was admitted with chief complaints of abdominal pain in the upper abdomen and a weight loss of approximately 5 kg over 4 mo. Carbohydrate antigen(CA) 125,carcinoembryonic antigen, and CA 199 were normal. An abdominal computed tomography scan found multiple nodules in the right lobe of the liver that measured approximately 13.5 cm × 10.8 cm × 21.4 cm. Immunohistochemical staining results showed that CD10 and CD56 were positive, and the patient was diagnosed with SPT of the pancreas with liver metastasis. The patient underwent percutaneous cryoablation and interventional embolization. During the 5-year follow-up, the patient remained disease-free after cryoablation, with relatively normal immune function.CONCLUSION Herein, we for the first time report the treatment of liver metastasis from SPT of the pancreas using cryoablation plus interventional embolization, which could be a promising alternative therapy for pancreatic SPT liver metastasis.

Solid pseudopapillary tumor of the pancreas:A systematic review of clinical,surgical and oncological characteristics of 1384 patients underwent pancreatic surgery

Background:Pancreatic solid pseudopapillary tumors(SPTs)are rare clinical entity,with low malignancy and still unclear pathogenesis.They account for less than 2%of exocrine pancreatic neoplasms.This study aimed to perform a systematic review of the main clinical,surgical and oncological characteristics of pancreatic SPTs.Data sources:MEDLINE/PubMed,Web of Science and Scopus databases were systematically searched for the main clinical,surgical and oncological characteristics of pancreatic SPTs up to April 2021,in accordance with the preferred reporting items for systematic reviews and meta-analyses(PRISMA)standards.Primary endpoints were to analyze treatments and oncological outcomes.Results:A total of 823 studies were recorded,86 studies underwent full-text reviews and 28 met inclusion criteria.Overall,1384 patients underwent pancreatic surgery.Mean age was 30 years and 1181 patients(85.3%)were female.The most common clinical presentation was non-specific abdominal pain(52.6%of cases).Mean overall survival was 98.1%.Mean recurrence rate was 2.8%.Mean follow-up was 4.2 years.Conclusions:Pancreatic SPTs are rare,and predominantly affect young women with unclear pathogenesis.Radical resection is the gold standard of treatment achieving good oncological impact and a favorable prognosis in a yearly life-long follow-up.

Synchronous intraoperative radiofrequency ablation for multiple liver metastasis and resection of giant solid pseudopapillary tumors of the pancreas

The solid pseudopapillary tumors of the pancreas （SPTP） are rare tumors, which are commonly found in adolescent women. Radical surgical resection of the primary tumor or metastases is the standard treatment for SPTP and could achieve long-term survival. We reported a case of a 20-year-old female with multiple liver metastases of SPTP, and performed surgical resection for primary tumor 14 cm in diameter and 2 major liver metastases （both 5 cm in diameter）, radiofrequency ablation （RFA） for small lesions and one major liver metastase 6 cm in diameter successfully. No evidence of recurrence in situ or in the liver was found by computed tomography （CT） scan 3 months after the operation. RFA is a safe and effective treatment for unresectable multiple liver metastases of SPTP.

Pancreatic head region lymph node tuberculosis mimicking pancreatic solid pseudopapillary tumor

Tuberculosis （TB） is a common disease in developing countries, and even in developed countries; its incidence is rising. Pancreatic head regional lymph node TB is uncommon, and isolated involvement is rare. Pre-operative diagnosis of pancreatic head regional lymph node TB is difficult and may mimic pancreatic malignant or benign lesions. We herein present a case of lymph node TB in the pancreatic head region mimicking a pancreatic solid pseudopapillary tumor in a 40-year-old female patient.

Pregnancy Complicated With a Giant Pancreatic Tumor and Decompensation of Liver Cirrhosis:A Case Report and Literature Review

Pregnancy with solid pseudopapillary tumor of the pancreas(SPTP)is rare.Because pregnancy hormones may cause tumor progression,the management and treatment of SPTP need to balance the safety of pregnant women and fetuses with surgical treatment.We reported a case of a giant pancreatic tumor diagnosed during pregnancy that was considered to be SPTP.Examinations also showed hepatitis B virus infection and severe decompensation of liver cirrhosis.Medical termination of pregnancy was performed.The patient has lived with the tumor until now without surgery.We retrieved the published case reports,summarized the clinical characteristics of pregnancy with SPTP,and explored its management during the perinatal period.Most patients with SPTP have a good prognosis with good maternal and fetal outcomes,and it is important to choose an appropriate treatment method and timing.However,pregnancy combined with decompensated liver cirrhosis needs to be terminated in a timely manner because of its high-risk status.

Pancreatic cystic tumors:an update

Pancreatic cystic tumors(PCTs)comprise a heterogeneous group of entities,accounting for 2%to 10%of pancreatic lesions.The most common types are intraductal papillary mucinous neoplasms(IPMNs),mucinous cystic neoplasm(MCN),and serous cystic neoplasm(SCN),which account for approximately 90%of PCTs.This review discusses updates in pathologic features,malignant transformation,biologic behavior,and molecular evolution of PCTs.IPMN includes main duct and branch duct types.These can also be classified into 4 histologic subtypes based on cell lineages of differentiation,and may be associated with different tumorigenic pathways and clinicopathologic characteristics.The gastric type is the most common and is rarely associated with carcinomas,whereas the pancreatobiliary type is significantly more associated with invasive carcinoma.MCN is a mucinous cystic lesion with the presence of ovarian-type pericystic stroma.Prognosis of the resected non-invasive MCN is excellent,but the long-term survival of MCNs with invasive carcinoma may be poor.SCN includes microcystic adenoma,macrocystic adenoma,and solid variant serous adenoma.Serous cystadenocarcinoma is defined by the presence of distant metastases,which is rare in literature.Intraductal tubulopapillary neoplasm is characterized by uniformly high-grade dysplasia and ductal differentiation without overt production of mucin,with high risk for developing invasion.Acinar cell cystadenoma is a rare benign lesion with acinar differentiation.In addition,some pancreatic neuroendocrine tumors may assume a cystic configuration,sometimes referred to as cystic pancreatic endocrine neoplasm tumor,with a lower pathologic stage.Solid pseudopapillary tumor is composed of poorly cohesive monomorphic epithelial cells forming solid and pseudopapillary structures,with excellent prognosis.