Solid-pseudopapillary Neoplasms of the Pancreas is still an Enigma: a Clinicopathological Review

Abstract

The solid-pseudopapillary neoplasm of the pancreas is a rare but enigmatic entity occurring mainly in young women. Since the first description by V. Frantz in 1959 the terminology of this tumor has continuously changed but it has remained simply descriptive, because the exact histogenesis is still obscure. Although in majority of cases the survival is excellent, nevertheless, the expected prognosis is not exactly predictable. In this review the authors aim to summarize its clinico-pathological features, the expected biological behavior, the molecular alterations, the immune phenotype and discuss the putative histogenesis. From diagnostic point of view, the salient histological characteristic findings are analyzed that would help to differentiate it from other, look-alike pancreatic tumors, and suggestions are made about the desirable content of the histological report.

Keywords: Histogenesis; Pancreas; Review; Solid-pseudopapillary neoplasm.

Fig. 1

Pathological characteristics of solid-pseudopapillary neoplasm. a The tumor is sharply demarcated; b Circumscribed tumor with necrotic-hemorrhagic, degenerative changes; c Connective tissue capsule around the tumor (Picrosirius red, ×100); d Rich vascularization is seen (HE, ×100); e Solid pattern (HE, ×100); f pseudopapillary pattern (PAS, ×200); g Hyalinized stroma (PAS, ×200); h Bland, monomorphous nuclei (PAS, ×200); i Numerous, hyalinic globules (PAS, ×200); j Cholesterol crystals with multinucleated giant cells (PAS, ×100)

Fig. 2

Immunohistochemical characteristics of solid-pseudopapillary neoplasm. a very low Ki-67 score (×200); b nuclear β-catenin expression (×100); c cyclin D1 expression (×100); d AAT positivity (×200); e CD56 expression (×400); f loss of E-cadherin (×200); g Progesteron receptor positive expression (×100); h CD99 expression (×200); i SOX-11 nuclear positivity (×100)