title: Epithelioid inflammatory myofibroblastic sarcoma: a clinicopathological, immunohistochemical and molecular cytogenetic analysis of five additional cases and review of the literature.
abstract: BACKGROUND
  To explore the clinical characteristics and pathological features of epithelioid inflammatory myofibroblastic sarcoma (EIMS) with emphasis on the diagnostic spectrum.
  
  
  METHODS
  The clinical data and histological features in 5 additional cases of EIMS were retrospectively reviewed. Immunohistochemical study and interphase fluorescence in situ hybridization (FISH) analysis were carried out.
  
  
  RESULTS
  There were 2 males and 3 females with age at presentation ranging from 15 to 58 years (mean, 37 years). All 5 tumors were intra-abdominal with 2 arising in the mesentery and 1 each in the omentum, rectum and transverse colon. The tumor size ranged from 5 to 20 cm in maximum diameter (mean, 10.7 cm). Histologically, all 5 tumors were composed predominantly of large epithelioid cells possessing vesicular nuclei, prominent nucleoli, and amphophilic cytoplasm. Mitotic figures were easily identified (mean, 20/10HPF). Tumor cells were arranged in clusters or sheets embedded in a myxoid stroma containing prominent neutrophils. A minor component of spindle cells was present in focal areas. By immunohistochemistry, all 5 cases were positive for anaplastic lymphoma kinase (ALK) with a nuclear membrane pattern in 4 and cytoplasmic staining with perinuclear accentuation in 1. Besides ALK, tumor cells stained variably for desmin (4/5), alpha smooth muscle actin (2/5), muscle-specific actin (1/2) and pan-cytokeratin (1/4). FISH analysis demonstrated the presence of ALK rearrangement in all 5 cases. Of 5 patients, 3 developed local recurrence, 1 died of disease 8 months after surgery.
  
  
  CONCLUSIONS
  EIMS represents a highly aggressive variant of inflammatory myofibroblastic tumor characterized by epithelioid morphology, prominent neutrophilic infiltrate, and nuclear membrane staining of ALK with ALK rearrangement. As patients with ALK-rearrangement tumors may benefit from targeted therapy, accurate diagnosis of EIMS is very important. Familiar with the characteristic features of EIMS will help pathologists avoid misdiagnosing the tumor as other malignancies.
authors.affiliation: Department of Pathology, Fudan University Shanghai Cancer Center, Fudan University, 270 Dong An Road, Shanghai, 200032, China.|Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Yu
authors.affiliation: Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University and Shanghai Respiratory Research Institute, Shanghai, 200032, China.
authors.forename: Jinguo
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Pathology, Fudan University Shanghai Cancer Center, Fudan University, 270 Dong An Road, Shanghai, 200032, China.|Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
authors.forename: I Weng
authors.initials: IW
authors.lastname: Lao
authors.affiliation: Department of Medical Oncology, Fudan University Shanghai Cancer Center, Fudan University, Shanghai, 200032, China.|Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Luo
authors.affiliation: Department of Pathology, Fudan University Shanghai Cancer Center, Fudan University, 270 Dong An Road, Shanghai, 200032, China. softtissuetumor@163.com.|Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China. softtissuetumor@163.com.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D000077548:Anaplastic Lymphoma Kinase; D014408:Biomarkers, Tumor / Q000378:metabolism*; D020732:Cytogenetic Analysis; D015622:Epithelioid Cells / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D007249:Inflammation; D008297:Male; D008875:Middle Aged; D058628:Myofibroblasts / Q000378:metabolism / Q000473:pathology; D009379:Neoplasms, Muscle Tissue / Q000175:diagnosis* / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D012189:Retrospective Studies; D012509:Sarcoma / Q000175:diagnosis* / Q000378:metabolism; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D020794:Receptor Protein-Tyrosine Kinases
keywords: Fluorescence in situ hybridization; Gastrointestinal tract; Inflammatory myofibroblastic tumor; RANBP2-ALK; Soft tissue tumor