**7. Solid pseudopapillary neoplasms (SPPNs)**

SPPNs represent 9% of all cystic pancreatic tumors and have the major incidence in young female patients (second–third decade). SPPNs are a neoplasm of unknown, not well‐defined origin: in fact, in the past, various descriptive names were employed. The macroscopic appearances of SPPNs are large solid masses (8–10 cm in size) and well encapsulated, and often the cut section shows areas of hemorrhage, cystic degeneration, and solid areas. The micro‐ scopic features are polygonal epithelioid cells that form solid pseudopapillary structures alternated hemorrhagic necrotic pseudocyst. There is also evident extensive vascular network, often with infiltrative growth pattern. Alterations in the antigen‐presenting cell/beta‐catenin pathway [42] and vimentine positive can be present. The histologic picture may resemble closely to pancreatic endocrine neoplasms (PEN) but chromogranin is negative. In some cases, histologic criteria of malignancy such as high nuclear grade, venous invasion, and atypical cells may be observed; the metastatic spread is possible (10–15% of cases). SPPNs can be located in all side of the pancreas. Clinical appearances are abdominal pain, palpable mass, nausea/ vomiting, jaundice, and weight loss. The imaging examinations (CT, MRI, and EUS) show a solid and cystic masses with a well‐defined and thick capsule with sometimes peripheral calcifications without septations. EUS‐FNA provides little information. SPPNs can be consid‐ ered lesions with low malignity and rare occurrence of metastasis, usually hepatic (10–15%). The recommended treatment is surgery and the complete resection is often possible (94%); the cure rate reaches 85–95% of patients [6, 44]. The pancreatic resection is based on the location of neoplasm in the gland [43, 44].
