Solid pseudopapillary neoplasm of pancreas: Two case reports.

RATIONALE

About 8384 cases of solid pseudopapillary neoplasms (SPN) of pancreas have been published in English literature, from 1933 to 2018. This is a low-grade tumor that usually occurs in children but is rare in adults and, in exceptional cases, can show extrapancreatic localization. In this paper we present 2 unusual cases of SPNs, 1 with retroperitoneal location (case 1) and 1 that was firstly diagnosed as a G1 neuroendocrine tumor (NET) and showed hepatic metastases after 13 years (case 2).

PATIENT CONCERNS

No symptoms in first case. The tumor was incidentally diagnosed, during ultrasound examination. In the second case, the metastasis was observed during regular follow-up.

DIAGNOSES

The diagnosis was established based on the histological features and immunohistochemical profile that showed positivity for vimentin, nuclear β-catenin, cyclin D1, CD10, and SRY-related high-mobility group box 11 and negativity for maspin.

INTERVENTIONS

Surgical excision, in both cases.

OUTCOMES

No recurrences in first case, at 5 months after diagnosis. Hepatic metastases in the second case, at 13 years after diagnosis, with portal invasion after another 15 months.

LESSONS

Without a complex immunoprofile, SPN can be misdiagnosed as NET. SPN can be a low-grade tumor but long-time follow-up is mandatory to detect delayed metastases. A correct diagnosis is necessary for a proper therapeutic management.