[Solid pseudopapillary neoplasms of the pancreas : Diagnostics, surgical treatment and postoperative outcome].

Background: Malignant solid pseudopapillary neoplasms (SPN) are rare tumor entities of the pancreas. The prognosis for SPN is generally excellent, although some tumors have malignant potential and tend to metastasize or relapse.

Objective: The aim was to investigate whether there are histopathological or surgical risk factors that enable the biological potential of SPN to be estimated.

Patients and methods: Data from patients with SPN treated in two large German pancreas centers from 2009 to 2018 were evaluated with respect to the occurrence of SPN, surgical management, histopathological tumor characteristics and the postoperative outcome.

Results: A total of 22 patients with SPN (17 women, 5 men) were operated on. The median age of the patients was 37 years (range 19-69 years). At the time of surgery 20 patients showed tumor growth limited to the pancreas. A female patient with recurrence of an externally resected SPN had lymph node involvement. Another female patient had a hepatic metastatic recurrence (Union Internationale contre Cancer (UICC) stage IV) of an externally resected SPN. Although all patients survived recurrence-free during the follow-up, this patient developed liver metastases again. The survival rate up to the end of the follow-up (median 43 months; range 1-132 months) of this study was 100%.

Conclusion: There is a lack of knowledge of the possible parameters that can be used to predict the biological behavior of SPN. Apart from an increased likelihood of recurrence after resection of an SPN recurrence, no clear risk factors could be identified in the examined patient collective that could indicate an increased malignant potential and a possibly poorer outcome. Only a radical surgical resection with lymphadenectomy enables a reliable assessment of the tumor stage and the removal of possibly affected lymph nodes, which could be the cause of a recurrence if left intact.