title: Cytopathologic features of epithelioid inflammatory myofibroblastic sarcoma with correlation of histopathology, immunohistochemistry, and molecular cytogenetic analysis.
abstract: BACKGROUND
  Epithelioid inflammatory myofibroblastic sarcoma (E-IMS) is a recently established rare variant of inflammatory myofibroblastic tumor. It is characterized by a distinctive constellation of clinical, pathological, and molecular features, including a nearly exclusive intraabdominal location, strong male predilection, aggressive clinical course, predominance of epithelioid tumor cells, and Ran-binding protein 2 (RANBP2)-anaplastic lymphoma kinase (ALK) fusion in the majority of cases. To the authors' knowledge, the cytologic features of E-IMS have not been described to date.
  
  
  METHODS
  Cases of E-IMS that had corresponding cytology were searched. Six cytology samples (1 fine-needle aspiration sample, 2 imprint samples, and 3 effusion fluids) containing tumor cells were identified in 5 patients with E-IMS.
  
  
  RESULTS
  The cytomorphology included large monotonous epithelioid cells arranged in loose aggregates or singly, with admixed myxoid stroma, and an inflammatory background rich in neutrophils. The tumor cells had a large, round, eccentric nucleus with vesicular chromatin, prominent nucleoli, and moderate amounts of pale cytoplasm. Delicate thin-walled branching vessels traversing tumor aggregates was a prominent feature in a fine-needle aspiration sample. Immunohistochemically, ALK was positive in all 5 tumors, with a nuclear membranous staining pattern noted in 3 cases and a cytoplasmic pattern observed in the other 2 cases. ALK rearrangement was confirmed in all 5 tumors by molecular genetic studies.
  
  
  CONCLUSIONS
  The cytologic features of E-IMS recapitulate its histologic characteristics. E-IMS merits inclusion in the differential diagnosis of any intraabdominal, large epithelioid cell neoplasm. Confirmation of ALK rearrangement is advisable because patients may benefit from targeted therapies.
authors.affiliation: Department and Graduate Institute of Pathology, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Jen-Chieh
authors.initials: JC
authors.lastname: Lee
authors.affiliation: Department of Surgery, Far Eastern Memorial Hospital, New Taipei City, Taiwan.
authors.forename: Jiann-Ming
authors.initials: JM
authors.lastname: Wu
authors.affiliation: Department and Graduate Institute of Pathology, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Jau-Yu
authors.initials: JY
authors.lastname: Liau
authors.affiliation: Department of Pathology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Hsuan-Ying
authors.initials: HY
authors.lastname: Huang
authors.affiliation: Department of Pathology, Far Eastern Memorial Hospital, New Taipei City, Taiwan.
authors.forename: Cheng-Yu
authors.initials: CY
authors.lastname: Lo
authors.affiliation: Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: I-Shiow
authors.initials: IS
authors.lastname: Jan
authors.affiliation: Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Jason L
authors.initials: JL
authors.lastname: Hornick
authors.affiliation: Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Qian
mesh_terms: D000293:Adolescent; D000328:Adult; D000077548:Anaplastic Lymphoma Kinase; D044963:Biopsy, Fine-Needle / Q000379:methods; D003581:Cytodiagnosis / Q000379:methods; D020732:Cytogenetic Analysis / Q000379:methods*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008113:Liver Neoplasms / Q000235:genetics / Q000473:pathology*; D008175:Lung Neoplasms / Q000235:genetics / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D058628:Myofibroblasts / Q000473:pathology; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D012042:Registries; D012494:Sampling Studies; D012509:Sarcoma / Q000235:genetics / Q000473:pathology*; D012680:Sensitivity and Specificity
chemical_list: D009687:Nuclear Proteins; C091775:ran-binding protein 1; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D020794:Receptor Protein-Tyrosine Kinases
keywords: RANBP2 (Ran-binding protein 2)-ALK; anaplastic lymphoma kinase (ALK); cytology; epithelioid; fine-needle aspiration; inflammatory myofibroblastic tumor; sarcoma