title: Well-differentiated papillary mesothelioma, possibly giving rise to diffuse malignant mesothelioma: a case report.
abstract: Well-differentiated papillary mesothelioma (WDPM) is a distinct subtype of mesothelial tumor from diffuse malignant mesothelioma (DMM), with an uncertain malignant potential. The relationship between WDPM and DMM, with regard to the ability of the former to develop into the latter, is also unknown. A 58-year-old woman, diagnosed with a rectal carcinoid tumor, underwent removal of the lymph nodes via the abdomen in 2004. A large number of white miliary nodules were identified on the mesentery and peritoneum, which were histologically diagnosed as WDPM. No further therapy was administered, but the patient was followed-up using imaging methods. Seven years later, an abdominal wall mass was discovered using positron emission tomography-computed tomography, and a laparotomy biopsy was performed. DMM was diagnosed, because mesothelioma with extended invasion had been histologically identified. Mesothelioma similar to papillary proliferation was present on the outer layer of the peritoneum, and an infiltrating lesion with continuous restiform or solid-like structures was noted. WDPM was believed to have undergone malignant transformation. Compared to DMM, WDPM has a good prognosis and is considered a benign or borderline neoplasm. Our findings suggest that WDPM does have malignant potential, however, because histological findings indicated a malignant transformation of WDPM to DMM.
authors.affiliation: Department of Pathology, Kanagawa Cancer Center, Yokohama-shi 241-0815, Japan. washimik@kcch.jp
authors.forename: Kota
authors.initials: K
authors.lastname: Washimi
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Yokose
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Amitani
authors.forename: Mamiko
authors.initials: M
authors.lastname: Nakamura
authors.forename: Sachie
authors.initials: S
authors.lastname: Osanai
authors.forename: Hiroko
authors.initials: H
authors.lastname: Noda
authors.forename: Kae
authors.initials: K
authors.lastname: Kawachi
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Takasaki
authors.forename: Makoto
authors.initials: M
authors.lastname: Akaike
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Kameda
mesh_terms: D001201:Ascites / Q000473:pathology; D014408:Biomarkers, Tumor / Q000378:metabolism; D001706:Biopsy; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000601:surgery; D008654:Mesothelioma / Q000175:diagnosis* / Q000378:metabolism / Q000601:surgery; D000086002:Mesothelioma, Malignant; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000175:diagnosis*; D010534:Peritoneal Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000601:surgery; D049268:Positron-Emission Tomography; D013997:Time Factors; D057832:Watchful Waiting
chemical_list: D014408:Biomarkers, Tumor