Solid pseudopapillary neoplasm of the pancreas

Abstract

Solid pseudopapillary neoplasms are rare. This article reviews the clinical and pathologic features of solid pseudopapillary neoplasm of the pancreas, including the epidemiology, cytology, molecular pathology, differential diagnosis, treatment, and prognosis. Solid pseudopapillary neoplasms are low-grade malignant tumours of the pancreas characterized by poorly cohesive epithelial cells with solid and pseudopapillary patterns. Solid pseudopapillary neoplasms occur predominantly in young women. Although solid pseudopapillary neoplasms can occur throughout the pancreas, they arise slightly more frequently in the tail of the pancreas. The aetiology is unknown. Extremely rare cases have been reported in the setting of familial adenomatous polyposis. There are no symptoms unique to solid pseudopapillary neoplasms, however, the most common symptom is abdominal pain or discomfort. The features of solid pseudopapillary neoplasms on computed tomography imaging are indicative of the pathologic changes within the tumour. Typically, well-demarcated masses with variably solid and cystic appearances. Microscopically, these tumours are composed of epithelial cells forming solid and pseudopapillary structures, frequently undergoing haemorrhagic cystic degeneration. Typically, these tumours express nuclear and/or cytoplasmic β-catenin. Almost all solid pseudopapillary neoplasms harbour mutations in exon 3 of CTNNB1, the gene encoding β-catenin. The overall prognosis is excellent, and most patients are cured by complete surgical resection.

Keywords: Cancer of pancreas; Non-ductal pancreatic tumours; Pancreas; Pancreatic neoplasms; Solid pseudopapillary neoplasm of the pancreas.

Figure 1

Solid pseudopapillary neoplasm of the pancreas. A: The tumour shows pseudopapillae formed by poorly cohesive cells arranged around hyalinized fibrovascular stalks (200 ×); B: The tumour consists of cells forming solid and pseudopapillary structures (200 ×); C: Solid pseudopapillary neoplasm of the pancreas shows characteristic eosinophilic cytoplasmic hyaline globules (400 ×); D: An example showing foamy histiocytes (200 ×); E: These are cholesterol clefts surrounded by foreign body giant cells (200 ×); F: The tumour shows nuclear and cytoplasmic expression of β-catenin (200 ×); G: The tumour shows immunolabelling for CD56 (200 ×); H: The tumour is positive for vimentin (200 ×); I: The tumour shows immunolabelling for CD10 (200 ×); J: Solid pseudopapillary neoplasm of the pancreas shows nuclear positivity for cyclin D1 (200 ×).