title: Metastatic malignant mesothelioma presenting as colonic polyps.
abstract: A 66-year-old male engineer diagnosed with malignant pleural mesothelioma 4 years previously had thoracotomy, radiotherapy, and chemotherapy. He was followed regularly with chest computed tomography (CT) scan and had been asymptomatic. During one of his physical examinations, routine sigmoidoscopy showed incidental colonic polyps which were biopsied. Subsequently, recurrence of pleural mesothelioma and peritoneal involvement by mesothelioma was documented. Two of the polyps showed metastatic malignant mesothelioma in the lamina propia which strongly resembled adenocarcinoma histologically causing difficulty in making definitive diagnosis. Review of the literature disclosed no previously documented similar occurrence. This case shows the importance of clinical history and ancillary laboratory procedures such as immunohistochemistry and electron microscopy to avoid diagnostic pitfalls.
authors.affiliation: Department of Laboratories, North Shore University Hospital-New York University School of Medicine, Manhasset 11030, USA.
authors.forename: A V
authors.initials: AV
authors.lastname: Masangkay
authors.forename: M
authors.initials: M
authors.lastname: Susin
authors.forename: R
authors.initials: R
authors.lastname: Baker
authors.forename: R
authors.initials: R
authors.lastname: Ward
authors.forename: E
authors.initials: E
authors.lastname: Kahn
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology; D000368:Aged; D001706:Biopsy; D003111:Colonic Polyps / Q000473:pathology* / Q000556:secondary* / Q000648:ultrastructure; D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D008654:Mesothelioma / Q000473:pathology* / Q000556:secondary / Q000648:ultrastructure; D008854:Microscopy, Electron; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D010534:Peritoneal Neoplasms / Q000473:pathology / Q000648:ultrastructure; D010997:Pleural Neoplasms / Q000473:pathology / Q000648:ultrastructure