title: Unusual focal keratin expression in plexiform angiomyxoid myofibroblastic tumor: A case report and review of the literature.
abstract: BACKGROUND
  Plexiform angiomyxoid myofibroblastic tumor (PAMT), also known as plexiform fibromyxoma, is a rare distinctive benign intramural tumor, typical of gastric antrum, commonly causing mucosal ulceration with upper gastrointestinal bleeding and anemia, effectively treated by complete surgical resection usually accomplished by distal gastrectomy.
  
  
  RESULTS
  We herein report a 47-year-old man presenting with a syncopal episode, regurgitation and epigastric discomfort, bearing a gastric antral myxoid plexiform tumor positive for α-smooth muscle actin, vimentin and, partially, for caldesmon, desmin, and CD10; CD117, DOG1, CD34, S100, CAM5.2, CK20, CK7, EMA, p53, CDX2, chromogranin A, synaptophysin, anaplastic lymphoma kinase, Melan-A, and HMB-45 were all negative. All these features are typical of PAMT. Of note, focal positivity for AE1/AE3 and pan-CK KL1 was also present.
  
  
  CONCLUSIONS
  The finding of a focal keratin expression in PAMT contributes to enlarge the immunophenotypic spectrum of this tumor type and is relevant for avoiding presurgical misdiagnoses which could ultimately lead to inappropriate overtreatment of patients with PAMT.
authors.affiliation: Department of Surgery, Catholic University Department of Pathology, Catholic University, Rome Department of Gastroenterology and Digestive Endoscopy, "A. Cardarelli" Hospital Department of Radiology, "A. Cardarelli" Hospital, Campobasso Department of Medicine, University of Padua School of Medicine, Padua, Italy and Department of Pathology, Treviso Regional Hospital, Treviso, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Quero
authors.forename: Teresa
authors.initials: T
authors.lastname: Musarra
authors.forename: Alfredo
authors.initials: A
authors.lastname: Carrato
authors.forename: Michelangelo
authors.initials: M
authors.lastname: Fici
authors.forename: Maurizio
authors.initials: M
authors.lastname: Martini
authors.forename: Angelo Paolo
authors.initials: AP
authors.lastname: Dei Tos
authors.forename: Sergio
authors.initials: S
authors.lastname: Alfieri
authors.forename: Riccardo
authors.initials: R
authors.lastname: Ricci
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D005350:Fibroma / Q000473:pathology* / Q000601:surgery; D005743:Gastrectomy; D006801:Humans; D007633:Keratins / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D013274:Stomach Neoplasms / Q000473:pathology* / Q000601:surgery
chemical_list: D014408:Biomarkers, Tumor; D007633:Keratins