title: Distinctive histopathologic findings of pancreatic hamartomas suggesting their "hamartomatous" nature: a study of 9 cases.
abstract: Pancreatic hamartoma is a rare tumor, and its characteristic histopathologic features have not yet been fully evaluated. In this study, we collected 9 cases of pancreatic hamartoma to elucidate distinctive histopathologic features that can serve to establish this tumor as a clear disease entity and thus formulate useful histopathologic criteria for this tumor. The cases comprised 4 men and 5 women with a mean age of 62.7 years. The average tumor diameter was 3.3 cm. All patients underwent surgical treatment, and none showed any recurrence postoperatively. Macroscopically, pancreatic hamartomas were well-demarcated tumors with a solid or solid and cystic appearance. Microscopically, these tumors comprised mature acini and small-sized to medium-sized ducts showing a distorted architecture with various amounts of fibrous stroma. Strikingly, the tumors consistently lacked concentric elastic fibers in their duct walls, peripheral nerves, and well-formed islets of Langerhans, all of which exist in both the normal and atrophic pancreas. Immunohistochemically, scattered chromogranin A-positive neuroendocrine cells were observed in the acinar and ductal components. Ductal components were positive for S-100 protein. Spindle-shaped stromal cells expressed CD34 and/or c-kit. These histopathologic features were distinct from those of 5 cases of pancreatic ductal adenocarcinoma, 3 cases of type 1 autoimmune pancreatitis (lymphoplasmacytic sclerosing pancreatitis), 3 cases of alcoholic chronic pancreatitis, and 5 cases of normal pancreas. In conclusion, pancreatic hamartomas share some distinctive histopathologic features and clinical outcomes (neither recurrence nor metastasis) that allow them to be interpreted as malformative lesions. The term "hamartoma" is appropriate for these unique lesions.
authors.affiliation: Department of Pathology, Saitama International Medical Center, Saitama Medical University, Hidaka, Japan. hyamag@saitama-med.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamaguchi
authors.forename: Shinichi
authors.initials: S
authors.lastname: Aishima
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Oda
authors.forename: Hiroki
authors.initials: H
authors.lastname: Mizukami
authors.forename: Takuma
authors.initials: T
authors.lastname: Tajiri
authors.forename: Sohsuke
authors.initials: S
authors.lastname: Yamada
authors.forename: Takashi
authors.initials: T
authors.lastname: Tasaki
authors.forename: Keisuke
authors.initials: K
authors.lastname: Yamakita
authors.forename: Koji
authors.initials: K
authors.lastname: Imai
authors.forename: Fumi
authors.initials: F
authors.lastname: Kawakami
authors.forename: Shigeo
authors.initials: S
authors.lastname: Hara
authors.forename: Keiji
authors.initials: K
authors.lastname: Hanada
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Iiboshi
authors.forename: Toshikatsu
authors.initials: T
authors.lastname: Fukuda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Imai
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Inoue
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Nagakawa
authors.forename: Shunji
authors.initials: S
authors.lastname: Muraoka
authors.forename: Toru
authors.initials: T
authors.lastname: Furukawa
authors.forename: Michio
authors.initials: M
authors.lastname: Shimizu
mesh_terms: D000368:Aged; D015415:Biomarkers; D053379:Chromogranin A / Q000378:metabolism; D005260:Female; D006222:Hamartoma / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D055099:Neuroendocrine Cells / Q000378:metabolism / Q000473:pathology; D010182:Pancreatic Diseases / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D009418:S100 Proteins / Q000378:metabolism
chemical_list: D015415:Biomarkers; D053379:Chromogranin A; D009418:S100 Proteins