title: Pigmented solid-pseudopapillary neoplasm of the pancreas.
abstract: A hitherto unrecognized variant of solid-pseudopapillary neoplasm of the pancreas is reported. The tumor presented in the pancreatic head of a 57-year-old female patient. It was a well-circumscribed, encapsulated nodule measuring 27 mm in diameter, with variegated yellow to brown and gray cut surface. Histologically, the neoplasm was composed of uniform polyhedral cells arranged around delicate fibrovascular cores retaining their solid pattern in the periphery, whereas central parts of the tumor were characterized by the formation of papillae and smaller pseudocysts. Neither mitotic activity nor invasive growth were found. Immunohistochemically, tumor cells were positive for vimentin, neuron-specific enolase, and CD56, whereas they were negative in reactions with antibodies directed against other neuroendocrine markers, cytokeratins, melanocytic markers, and pancreatic amylase. In addition to these typical findings, intracellular pigmented granules were found in the darker brown zones of the tumor. They were positively stained in periodic acid-Schiff reaction after diastase digestion, sudan black B, and in Schmorl stain. In contrast, they were not stained with Fontana-Masson, Ziehl-Neelsen, and Perls stains. Ultrastructurally, the pigment consisted of dense granules with lipid droplets resembling modified lysosomes. These results exclude the possibility of a melanogenic nature of the pigment and instead determine it as lipofuscin.
authors.affiliation: Department of Pathology, Medical Faculty Hospital, Pilsen, Czech Republic.
authors.forename: Ondrej
authors.initials: O
authors.lastname: Daum
authors.forename: Radek
authors.initials: R
authors.lastname: Sima
authors.forename: Petr
authors.initials: P
authors.lastname: Mukensnabl
authors.forename: Tomas
authors.initials: T
authors.lastname: Vanecek
authors.forename: Martina
authors.initials: M
authors.lastname: Brouckova
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Benes
authors.forename: Michal
authors.initials: M
authors.lastname: Michal
mesh_terms: D019002:CD56 Antigen / Q000032:analysis; D002291:Carcinoma, Papillary / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D003598:Cytoskeletal Proteins / Q000235:genetics; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D008875:Middle Aged; D020125:Mutation, Missense; D010179:Pancreas / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D010751:Phosphopyruvate Hydratase / Q000032:analysis; D015534:Trans-Activators / Q000235:genetics; D014746:Vimentin / Q000032:analysis; D051176:beta Catenin
chemical_list: D019002:CD56 Antigen; C495270:CTNNB1 protein, human; D003598:Cytoskeletal Proteins; D015534:Trans-Activators; D014746:Vimentin; D051176:beta Catenin; D010751:Phosphopyruvate Hydratase