title: ALK-positive diffuse large B-cell lymphoma of the stomach associated with a clathrin-ALK rearrangement.
abstract: ALK-positive diffuse large B-cell lymphoma is a rare, recently characterized lymphoma subtype that shows granular cytoplasmic ALK expression. This report describes a primary gastric ALK-positive B-lineage lymphoma in which a clathrin (CLTC)-ALK fusion was identified by RT-PCR and direct sequencing of the breakpoint. This confirmed the presence of t(2;17)(p23;q23) involving the CLTC gene and is only the 4th report of such a translocation in this lymphoma subtype and the first to describe this tumor within the stomach. As in previous reports, immunophenotyping showed the malignant cell to be a terminally differentiated B-lineage cell characterized by the absence of B-cell antigens and expression of antigens associated with plasma cell differentiation. This case confirms the existence of such a lymphoma subtype arising in extranodal locations and underscores the importance of detailed immunophenotyping and specialized molecular genetic investigations in confirming the diagnosis.
authors.affiliation: Department of Tissue Pathology, Belfast City Hospital, Belfast City Hospital Trust, Northern Ireland, United Kingdom.
authors.forename: D T
authors.initials: DT
authors.lastname: McManus
authors.forename: M A
authors.initials: MA
authors.lastname: Catherwood
authors.forename: P D
authors.initials: PD
authors.lastname: Carey
authors.forename: R J G
authors.initials: RJ
authors.lastname: Cuthbert
authors.forename: H D
authors.initials: HD
authors.lastname: Alexander
mesh_terms: D000328:Adult; D000077548:Anaplastic Lymphoma Kinase; D001483:Base Sequence; D002966:Clathrin / Q000235:genetics*; D006801:Humans; D016393:Lymphoma, B-Cell / Q000235:genetics*; D016403:Lymphoma, Large B-Cell, Diffuse / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D011505:Protein-Tyrosine Kinases / Q000235:genetics*; D020794:Receptor Protein-Tyrosine Kinases; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics*; D014178:Translocation, Genetic
chemical_list: D002966:Clathrin; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases