title: A Solid Pseudopapillary Neoplasm of the Pancreas Associated With IgG4-Related Pancreatitis: A Case Report.
abstract: A solid and cystic pancreatic lesion was incidentally found in a 62-year-old woman on abdominal computed tomography. The lesion was diagnosed as a solid pseudopapillary neoplasm by using endoscopic ultrasound-guided fine needle aspiration, and the tumor was resected. Histologically, the tumor cells had relatively small, round nuclei and papillary-like architecture in a hemorrhagic background. On immunohistochemical examination, the tumor cells were diffusely positive for nuclear β-catenin and cytoplasmic CD10. In addition, typical histological findings of IgG4-related pancreatitis (obstructive phlebitis, storiform-type fibrosis, and abundant IgG4-positive plasma cell infiltration) were found in the surrounding stroma of the solid pseudopapillary neoplasm. Postoperative workup failed to detect any other sclerotic lesions or serum IgG4 elevation, suggesting that the patient had no evidence of IgG4-related disease. To avoid misdiagnosis of a combined pancreatic neoplasm and fibro-inflammatory lesion, pathologists should consider such situations and make a definitive diagnosis after careful observation of all pancreatic lesions.
authors.affiliation: 1 Department of Tumor Pathology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Hatano
authors.affiliation: 2 Department of Pathology and Translational Research, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kawashima
authors.affiliation: 3 First Department of Internal Medicine, Gifu University Hospital, Gifu, Japan.
authors.forename: Takuji
authors.initials: T
authors.lastname: Iwashita
authors.affiliation: 4 Department of General and Cardiothoracic Surgery, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Kimura
authors.affiliation: 3 First Department of Internal Medicine, Gifu University Hospital, Gifu, Japan.
authors.forename: Masahito
authors.initials: M
authors.lastname: Shimizu
authors.affiliation: 1 Department of Tumor Pathology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Hara
mesh_terms: D001327:Autoimmune Diseases / Q000150:complications*; D014408:Biomarkers, Tumor / Q000032:analysis; D005260:Female; D006801:Humans; D007074:Immunoglobulin G; D007150:Immunohistochemistry; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000150:complications* / Q000473:pathology; D010195:Pancreatitis / Q000150:complications* / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; D007074:Immunoglobulin G
keywords: IgG4-related pancreatitis; autoimmune pancreatitis; case report; pancreas; solid pseudopapillary neoplasm