title: Incidental finding of multiple well-differentiated papillary mesotheliomas in peritoneum.
abstract: We present a case of multiple well-differentiated papillary mesotheliomas (WDPM) in the peritoneum found incidentally in a 63-year-old man with urothelial carcinoma of the bladder. When multiple tumors are seen, malignant mesothelioma should be excluded by histopathological examination as this may have a similar focal appearance to WDPM. True stromal invasion is by far the most reliable criterion of mesothelial malignancy. In doubtful cases, a conservative diagnostic approach has been recommended. Compared to malignant mesotheliomas, WDPMs are rare and have a relatively indolent clinical course with a good prognosis. Great care is needed when diagnosing mesothelial proliferations, given the crucial nature of a benign vs malignant diagnosis. No standardized treatment has yet been established.
authors.affiliation: Department of Pathology, Odense University Hospital, Odense, Denmark.
authors.forename: Mark
authors.initials: M
authors.lastname: Jakobsen
authors.affiliation: Department of Pathology, Odense University Hospital, Odense, Denmark.
authors.forename: Birte
authors.initials: B
authors.lastname: Engvad
authors.affiliation: Department of Urology, Odense University Hospital, Odense, Denmark.
authors.forename: Thor
authors.initials: T
authors.lastname: Jensen
authors.affiliation: Department of Pathology, Odense University Hospital, Odense, Denmark.
authors.forename: Niels
authors.initials: N
authors.lastname: Marcussen
mesh_terms: D002277:Carcinoma / Q000473:pathology / Q000601:surgery; D006801:Humans; D033162:Incidental Findings; D008297:Male; D008654:Mesothelioma / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D008875:Middle Aged; D010534:Peritoneal Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D010537:Peritoneum / Q000473:pathology* / Q000601:surgery; D001743:Urinary Bladder / Q000473:pathology / Q000601:surgery; D001749:Urinary Bladder Neoplasms / Q000473:pathology / Q000601:surgery
keywords: Mesothelioma; peritoneum