ALK activation by the CLTC-ALK fusion is a recurrent event in large B-cell lymphoma.
We present 3 cases of large B-cell lymphoma (LBCL) with a granular cytoplasmic staining for anaplastic lymphoma kinase (ALK). All of the cases showed striking similarities in morphology and immunohistochemical profile characterized by a massive monomorphic proliferation of CD20-/CD138+ plasmablast-like cells. In one of the cases, initially diagnosed as a null-type anaplastic large cell lymphoma (ALCL), the B-cell phenotype became evident only at recurrence. Fluorescent in situ hybridization (FISH) and molecular studies led to the detection of a CLTC-ALK rearrangement in all 3 cases, without any evidence of full-length ALK receptor expression. The associated t(2;17)(p23;q23) was demonstrated in the karyotype of 2 cases. Although a similar CLTC-ALK aberration was previously identified in ALK-positive T-/null cell ALCL and inflammatory myofibroblastic tumor, its association with ALK-positive LBCL seems to be specific and intriguing.
Department of Pathology, Center of Medical Genetics and Pediatric Oncology, Ghent University Hospital, Belgium.
Pascale
P
De Paepe
Mathijs
M
Baens
Han
H
van Krieken
Bruno
B
Verhasselt
Michel
M
Stul
Annet
A
Simons
Bruce
B
Poppe
Geneviève
G
Laureys
Paul
P
Brons
Peter
P
Vandenberghe
Frank
F
Speleman
Marleen
M
Praet
Chris
C
De Wolf-Peeters
Peter
P
Marynen
Iwona
I
Wlodarska
D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D000077548:Anaplastic Lymphoma Kinase; D001483:Base Sequence; D002648:Child; D002886:Chromosomes, Human, Pair 17; D002889:Chromosomes, Human, Pair 2; D002966:Clathrin / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D016393:Lymphoma, B-Cell / Q000235:genetics* / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases
D002966:Clathrin; D015514:Oncogene Proteins, Fusion; C408996:oncoprotein CLTCL-ALK; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases