title: Primary and metastatic high-grade pleomorphic sarcoma/malignant fibrous histiocytoma of the gastrointestinal tract: an approach to the differential diagnosis in a series of five cases with emphasis on myofibroblastic differentiation.
abstract: Primary and metastatic so-called malignant fibrous histiocytoma/undifferentiated high-grade pleomorphic sarcoma (MFH) is rare in the gastrointestinal (GI) tract with approximately 50 primary and five metastatic cases reported so far. We evaluated two primary gastric and three metastatic intestinal high-grade pleomorphic sarcomas with features of storiform-pleomorphic MFH. Gastric tumours occurred in a 79-year-old man and a 68-year-old woman. One patient died post-operatively, and the other was disease-free at 6 months. Three patients presented with GI metastasis 24, 60 and 0 months after diagnosis of MFH of the heart (n = 1) and the thigh (n = 2). Metastases were located in the small (n = 1) and large bowel (n = 2) and were characteristically pedunculated and polypoid with oedematous haemorrhagic stroma. Concurrent metastases (brain, lung, bone) were present in all three cases. Tumours expressed alpha-smooth muscle actin (four of five), platelet-derived growth factor receptor (PDGFR) alpha (three of three) and PDGFRbeta (two of three) but were negative for CD117, CD34 and other lineage-specific markers. Ultrastructural examination revealed myo/fibroblastic features. Both gastric MFH were wild type for KIT and PDGFRalpha. In conclusion, primary and metastatic MFH of the GI tract commonly express PDGFRalpha and show a myo/fibroblastic phenotype. They should be distinguished from a variety of primary and metastatic pleomorphic neoplasms, in particular high-grade sarcomatous GI stromal tumours (GIST), pleomorphic leiomyosarcoma, sarcomatoid carcinoma and other mimics.
authors.affiliation: Institute of Pathology, Klinikum Nürnberg, Prof.-Ernst-Nathan-Strasse 1, 90419 Nürnberg, Germany. abbas.agaimy@klinikum-nuernberg.de
authors.forename: Abbas
authors.initials: A
authors.lastname: Agaimy
authors.forename: Andreas
authors.initials: A
authors.lastname: Gaumann
authors.forename: Josef
authors.initials: J
authors.lastname: Schroeder
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Dietmaier
authors.forename: Arndt
authors.initials: A
authors.lastname: Hartmann
authors.forename: Ferdinand
authors.initials: F
authors.lastname: Hofstaedter
authors.forename: Peter H
authors.initials: PH
authors.lastname: Wünsch
authors.forename: Thomas
authors.initials: T
authors.lastname: Mentzel
mesh_terms: D000328:Adult; D000368:Aged; D002454:Cell Differentiation; D003937:Diagnosis, Differential; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000175:diagnosis*; D046152:Gastrointestinal Stromal Tumors / Q000473:pathology; D006338:Heart Neoplasms / Q000473:pathology; D051677:Histiocytoma, Malignant Fibrous / Q000175:diagnosis / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019042:Muscle Neoplasms / Q000473:pathology; D009362:Neoplasm Metastasis / Q000175:diagnosis / Q000473:pathology; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000378:metabolism; D012509:Sarcoma / Q000175:diagnosis / Q000473:pathology*; D013274:Stomach Neoplasms / Q000473:pathology; D013848:Thigh
chemical_list: D020796:Receptor, Platelet-Derived Growth Factor alpha