title: Merkel cell carcinoma with partial B-cell blastic immunophenotype: a potential mimic of cutaneous richter transformation in a patient with chronic lymphocytic lymphoma.
abstract: Merkel cell polyomavirus (MCPyV) is a DNA virus whose pathogenic mechanisms in Merkel cell carcinoma (MCC) are still being unraveled. Emerging reports of an association between MCPyV and chronic lymphocytic lymphoma (CLL) have begun to broaden our understanding of the oncogenic mechanisms of this virus and the known association between these 2 malignancies. Herein, we report a case of MCC demonstrating a B-cell immunophenotype arising in a patient with CLL being treated with rituximab. In this context, we discuss the differential diagnostic considerations, especially with cutaneous Richter transformation (diffuse large B-cell lymphoma). We also assessed for the presence of MCPyV in both the patient's MCC and the CLL. Finally, we provide a large meta-analysis of patients with CLL and MCC. Patients with both MCC and CLL have a dismal prognosis, with greater than 50% overall mortality within the first year and a half after MCC diagnosis.
authors.affiliation: *Department of Pathology, Duke University Medical Center, Durham, NC; †Eastern Dermatology and Pathology, Greenville, NC; and ‡Division of Hematologic Malignancies, Department of Medicine, Duke University Medical Center, Durham, NC.
authors.forename: John A
authors.initials: JA
authors.lastname: Papalas
authors.forename: Matthew S
authors.initials: MS
authors.lastname: McKinney
authors.forename: Evan
authors.initials: E
authors.lastname: Kulbacki
authors.forename: Sandeep S
authors.initials: SS
authors.lastname: Dave
authors.forename: Endi
authors.initials: E
authors.lastname: Wang
mesh_terms: D000368:Aged; D058846:Antibodies, Monoclonal, Murine-Derived / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001402:B-Lymphocytes / Q000473:pathology*; D015266:Carcinoma, Merkel Cell / Q000473:pathology* / Q000821:virology; D003520:Cyclophosphamide / Q000008:administration & dosage; D003937:Diagnosis, Differential; D017809:Fatal Outcome; D006801:Humans; D016130:Immunophenotyping; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000188:drug therapy / Q000473:pathology*; D008297:Male; D059965:Merkel cell polyomavirus; D009378:Neoplasms, Multiple Primary / Q000473:pathology* / Q000821:virology; D027601:Polyomavirus Infections / Q000473:pathology; D000069283:Rituximab; D012878:Skin Neoplasms / Q000473:pathology* / Q000821:virology; D014412:Tumor Virus Infections / Q000473:pathology; D014740:Vidarabine / Q000008:administration & dosage / Q000031:analogs & derivatives
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D000069283:Rituximab; D003520:Cyclophosphamide; D014740:Vidarabine; C024352:fludarabine