Anaplastic lymphoma kinase-positive large B-cell lymphoma (ALK LBCL) is a rare, aggressive subtype of diffuse large B-cell lymphoma with characteristic ALK rearrangements.
Anaplastic lymphoma kinase-positive (ALK+) large B-cell lymphoma (LBCL) is a rare subtype of non-Hodgkin B-cell lymphoma that exhibits a more aggressive clinical course and poorer prognosis than the typical diffuse large B-cell lymphoma.
Since the first discovery of anaplastic lymphoma kinase (ALK) in anaplastic large cell lymphoma (ALCL) by Morris et al in 1994, the number of ALK-positive neoplasms, either in the form of translocation or gain-of-function mutations, have been dramatically expanded from ALCL of T- and NK-cell origin, to diffuse large B-cell lymphoma, inflammatory myofibroblastic tumor (IMT), neuroblastoma, non-small cell lung carcinoma (NSCLC), undifferentiated anaplastic thyroid carcinoma, and rare type of sarcomas.
EML4-ALK transcripts were detected in 3/51 (5.9%) of reactive lymphoid tissues and 12/58 (20.7%) of lymphomas of different categories, including follicular lymphoma, diffuse large B-cell lymphoma and Hodgkin's disease.
These three cases suggest that different types of cytogenetic aberrations may involve the ALK gene in ALK-positive diffuse large B-cell lymphoma leading to peculiar immunohistochemical staining patterns.
In this report, we describe a diffuse large B-cell lymphoma associated with the classic t(2;5) translocation and both nuclear and cytoplasmic expression of ALK.