title: Chronic lymphocytic leukemia/small lymphocytic lymphoma with trisomy 12 and focal cyclin d1 expression: a potential diagnostic pitfall.
abstract: Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) and mantle cell lymphoma usually are distinctly different in regard to clinical presentation, morphology, immunophenotype, and molecular/genetic findings. In spite of this, select cases may show overlapping characteristics and represent a diagnostic challenge. Cyclin D1 immunohistochemical staining is usually envisioned as a definitive method for resolving this differential diagnosis, with positivity supporting a diagnosis of mantle cell lymphoma. We report a case involving a 58-year-old man with a diagnosis of CLL/SLL for several years. A lymph node excision was performed after increased adenopathy was noted in the cervical region. The excised lymph node showed typical morphologic findings of CLL/SLL, including the presence of characteristic proliferation centers. Cyclin D1 staining, using 3 different antibodies, was present in scattered prolymphocytes and paraimmunoblasts, mostly within proliferation centers. Fluorescence in situ hybridization and conventional cytogenetics demonstrated trisomy 12 and an absence of t(11;14) in lymph node tissue. Focal cyclin D1 expression by immunohistochemistry in nodal CLL/SLL is quite unusual and is discussed as a potential diagnostic pitfall.
authors.affiliation: Department of Pathology, Division of Hematopathology, Indiana University School of Medicine, Indianapolis 46202, USA. dpomalle@iupui.edu
authors.forename: Dennis P
authors.initials: DP
authors.lastname: O'Malley
authors.forename: Gail H
authors.initials: GH
authors.lastname: Vance
authors.forename: Attilio
authors.initials: A
authors.lastname: Orazi
mesh_terms: D002881:Chromosomes, Human, Pair 12 / Q000235:genetics*; D019938:Cyclin D1 / Q000096:biosynthesis* / Q000276:immunology; D003937:Diagnosis, Differential; D006801:Humans; D016130:Immunophenotyping / Q000379:methods; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000175:diagnosis*; D020522:Lymphoma, Mantle-Cell / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D014314:Trisomy / Q000175:diagnosis* / Q000235:genetics
chemical_list: D019938:Cyclin D1