title: ALK-positive inflammatory myofibroblastic tumor of the abdomen with widespread microscopic multifocality.
abstract: Inflammatory myofibroblastic tumor (IMT) is a locally aggressive neoplasm, most frequently occurring in the abdominal cavity as multiple recurrent nodules. We report a case of IMT in a 24-year-old male presenting as multiple nodules involving the omentum, the liver, and the colon. Spindle tumor cells expressed ALK with a cytoplasmic granular distribution, the CLTC-ALK fusion gene was demonstrated by reverse-transcriptase polymerase chain reaction analysis, and break-apart fluorescence in situ hybridization (FISH) probes for the ALK gene showed a pathological pattern (single red signal associated with 1/2 normal fused signals) highly suggestive for combined gene fusion and deletion. To reduce the surgically unresectable liver mass, the patient was treated with crizotinib, and after 4 months of treatment the disease was defined stable according to RECIST criteria. Interestingly, ALK and FISH/FICTION analysis revealed that tumor cells were widely dispersed as multiple microscopic foci or as single cells beneath the omental mesothelium. These findings indicate that IMT multifocality might result either from dissemination from the main tumor mass or development of multiple independent neoplastic foci; furthermore, they underline the need of omentectomy in abdominal IMT to obtain surgical radicality.
authors.affiliation: Pathology Section, Department of Molecular and Translational Medicine, University of Brescia, Spedali Civili, Brescia, Italy.
authors.forename: Luisa
authors.initials: L
authors.lastname: Lorenzi
authors.affiliation: Pathology Section, Department of Molecular and Translational Medicine, University of Brescia, Spedali Civili, Brescia, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Cigognetti
authors.affiliation: Pathology Section, Department of Molecular and Translational Medicine, University of Brescia, Spedali Civili, Brescia, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Medicina
authors.affiliation: Pathology Section, Department of Molecular and Translational Medicine, University of Brescia, Spedali Civili, Brescia, Italy.
authors.forename: Vilma
authors.initials: V
authors.lastname: Pellegrini
authors.affiliation: Pathology Section, Department of Molecular and Translational Medicine, University of Brescia, Spedali Civili, Brescia, Italy.
authors.forename: Piera
authors.initials: P
authors.lastname: Balzarini
authors.affiliation: Digestive Endoscopy, Department of Clinical and Experimental Sciences, University of Brescia, Spedali Civili, Brescia, Italy.
authors.forename: Renzo
authors.initials: R
authors.lastname: Cestari
authors.affiliation: Pathology Section, Department of Molecular and Translational Medicine, University of Brescia, Spedali Civili, Brescia, Italy facchett@med.unibs.it.
authors.forename: Fabio
authors.initials: F
authors.lastname: Facchetti
mesh_terms: D000008:Abdominal Neoplasms / Q000235:genetics / Q000473:pathology*; D000077548:Anaplastic Lymphoma Kinase; D014408:Biomarkers, Tumor / Q000032:analysis; D003110:Colonic Neoplasms / Q000556:secondary; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008113:Liver Neoplasms / Q000556:secondary; D008297:Male; D009379:Neoplasms, Muscle Tissue / Q000235:genetics / Q000556:secondary*; D009852:Omentum / Q000473:pathology; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D020794:Receptor Protein-Tyrosine Kinases / Q000032:analysis / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D015514:Oncogene Proteins, Fusion; C408996:oncoprotein CLTCL-ALK; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D020794:Receptor Protein-Tyrosine Kinases
keywords: ALK; inflammatory myofibroblastic tumor; microscopic multifocality; omentum