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Background:
Solid pseudopapillary neoplasms (SPN) are rare pancreatic tumors with low malignant potential.
Methods:
This is a retrospective analysis of 24 patients with a diagnosis of SPN who underwent resection. The main objective of this study was to describe the clinico-pathological features and surgical management of SPN.
Results:
Median age at diagnosis was 35.5 years (13 to 64). Most patients were female, 20/24, 83%. Most patients, 14/24, 58% were symptomatic at diagnosis, (11/24, 79% had abdominal pain). Median tumor size was 4.7cm (2.1 to 12) with 15/24, 62.5% occurring in the body or tail and 9/24, 37.5% in the head or neck of the pancreas. Most tumors were solid and cystic in nature (18/24, 75%), without calcifications (6/24, 25%) and encapsulated (16/24, 70%). There were 8/24, 33% pancreaticoduodenectomies, 4/24, 17% spleen-preserving distal pancreatectomies, 10/24, 42% distal pancreatectomy-splenectomy and 2/24, 8% central pancreatectomies. Major complications occurred in 3/24, 12.5% patients, with 6/24, 25% pancreatic leak rate (5/6, 83% ISGPF-type A leak). All cases displayed strong β-catenin, CD56, progesterone receptor, alpha-1 antitrypsin and neuron-specific-enolase staining with loss of E-cadherin. Most cases stained positive for vimentin (11/12, 92%) and CD10 (14/15, 93%). Three SPN were considered malignant, 3 developed liver metastases, 2 of which were initially found at presentation and 2 had local recurrence in the retroperitoneum. Two patients had evidence of lymphovascular invasion; one of them had lymph node involvement and eventually developed liver metastases. Curative resection of metastases was offered to 2 of the 3 patients, the other patient died of disseminated metastatic disease 5 years after diagnosis of recurrence, 10 years after initial pancreatic resection. Chemotherapy (gemcitabine and erlotinib) was given to only one patient with unresectable metastatic disease. Median follow-up period was 30 months (4 to 129), 21/24, 87.5% patients did not have recurrence and all patients except one were alive at the end of the study period.
Conclusions:
SPN are tumors with a low but real malignant potential. Metastases and lymphovascular invasion are the only features that can predict an aggressive behavior. Resection of liver metastases can offer cure to some of these patients with aggressive SPN.