Diagnostic challenges in an aggressive case of peripheralizing marginal zone lymphoma

Abstract

Evaluation of B-cell lymphomas benefits from cytogenetic analysis, however, limitations in conventional karyotyping and fluorescence in situ hybridization curtail their clinical utility. This case highlights value of cytogenetics in diagnosis of atypical B-cell lymphoma and discusses the benefits of new technology that can overcome the limitations of conventional cytogenetic studies. Mature B-cell neoplasms are relatively common neoplasms that can occasionally pose diagnostic challenges. In these cases, cytogenetics can be a useful tool for both diagnosis and prognosis. Common ancillary cytogenetics studies-conventional karyotyping and fluorescence in situ hybridization (FISH)-are almost universally available; however, both modalities have limitations that can curtail their utility in evaluation of mature B-cell neoplasms with atypical presentation or phenotypes. We present a case of peripheralizing marginal zone lymphoma with an atypical immunophenotype and clinical presentation and discuss the advantages and limitations of both conventional karyotyping and FISH in this setting. We also discuss how new next-generation sequencing (NGS) based methods, specifically referencing mate-pair sequencing, can bridge the gap between these limitations and why they should be considered in the toolkit of ancillary cytogenetic tests. 2 | CASE PRESENTATION A 68-year-old Caucasian man with a past medical history of obstructive sleep apnea, hypertension, and gout presented to a community hospital with shortness of breath, night sweats, and fatigue. His dyspnea had significantly worsened, in