Solid pseudopapillary neoplasm of the pancreas in children: A 15-year experience and the identification of a unique immunohistochemical marker

PurposeTo review our 15-year experience in the management of children with solid pseudopapillary neoplasm (SPPN) of the pancreas at a single pediatric institution, to delineate a unique immunohistochemical marker for SPPN, and to analyze cumulative data on this rare entity in the literature.MethodsWe did a retrospective analysis of the demographic data, clinical presentation, immunohistochemical characteristics, surgical approach, and long-term outcomes of all patients diagnosed with SPPN between 1997 and 2012.ResultsThere were 6 patients in the series, 5 females and 1 male. Median age at presentation and at surgery was 15 years (11-18 years). Abdominal pain was the presenting symptom in 5 cases and jaundice in 1 case. Two patients had a pancreatic head tumor and underwent a pylorus-preserving pancreaticoduodenectomy. Two patients had the tumor in the pancreatic tail and underwent a distal pancreatectomy with splenectomy. Two patients had the tumor in the pancreatic body and underwent a distal pancreatectomy with splenectomy in one case and with preservation of the spleen in the other. All tumors were completely resected with pathologic margins free of disease. The median maximum diameter was 6.8 cm (3 to 15 cm). On immunohistochemistry the tumors exhibited different combinations of non-specific markers like chromogranin, vimentin and neuron-specific enolase, but all tumors showed the highly SPPN-specific paranuclear dot-like immunoreactivity pattern for CD99 in the solid as well as in the pseudopapillary areas. No patient had metastasis at presentation. Median follow-up was 6.5 years (6 months to 15 years). There were no recurrences, no long-term metastasis, and all patients are disease-free.ConclusionOur series supports the concept that complete resection is necessary to achieve the best possible long-term results. Additionally, we demonstrate that SPPN exhibits a very unique immunostaining pattern for CD99 that is present in all cases.