[Solid pseudopapillary tumors of the pancreas: clinical and morphological characteristics, specific features of their immunophenotype, and diagnostic problems].

OBJECTIVE: To analyze 60 cases of solid pseudopapillary tumors (SPTs) of the pancreas, to reveal their most characteristic clinical and morphological features, and to study their possible histogenesis. MATERIAL AND METHODS: Sixty cases of SPTs of the pancreas underwent clinical, morphological, and immunohistochemical (IHC) examinations; a comparison group consisted of 86 pancreatic tumors of other histogenesis. RESULTS: It has been shown for the first time that SPTs are characterized by the nuclear expression of claudin 3 and the cytoplasmic expression of claudin 7. It has been also ascertained that the aberrant perinuclear (dot-like) expression of CD99 is a unique feature of these tumors. CONCLUSION: SPTs of the pancreas are distinguished by a diversity of clinical manifestations and morphological features, but have a unique immunophenotype, which can differentiate them from other types of pancreatic tumors.