title: Intravascular natural killer cell lymphoma mimicking mycosis fungoides: a case report and review of the literature.
abstract: Intravascular lymphoma is a rare entity. Most cases constitute a variant of extranodal diffuse large B-cell lymphoma, and only 10% of the published cases are of T-cell or histiocytic origin. Even fewer cases of intravascular natural killer (NK) cell lymphoma have been reported. To date, only the intravascular lymphoma of B-cell linage is recognized as a distinct entity by the WHO Classification. Here, we report the clinical, morphological, immunohistochemical, and molecular findings of a 72-year-old male patient with intravascular NK-cell lymphoma of the skin who initially presented with red skin efflorescences suspicious of mycosis fungoides. A skin biopsy revealed large cell infiltrates of NK/T-cell phenotype (CD3ε, CD4, CD8, CD56, and TIA-1), which were localized strictly intravascularly and which were positive for Epstein-Barr virus nucleic acid EBER (Epstein-Barr virus-encoded small RNA). Molecular studies revealed a germline configuration for the T-cell receptor consistent with the possibility of an NK-cell origin. At the beginning, the disease appeared to be limited to the skin with no sign of bone marrow involvement or leukemic dissemination. Chemotherapy was initiated; however, the patient subsequently developed meningiosis lymphomatosa with recurrent epileptic episodes and bone marrow infiltration with pancytopenia 7 months after primary admission. Finally, the patient passed away in a septic shock.
authors.affiliation: *Department of Pathology, Reference Center for Lymph Node Pathology and Hematopathology, University Hospital of Schleswig-Holstein, Luebeck, Germany; and †Department of Dermatology and Allergology, Center for Skin Diseases, Bad Cannstatt, Germany.
authors.forename: Niklas
authors.initials: N
authors.lastname: Gebauer
authors.forename: Ebba J
authors.initials: EJ
authors.lastname: Nissen
authors.forename: Peter von den
authors.initials: Pv
authors.lastname: Driesch
authors.forename: Alfred C
authors.initials: AC
authors.lastname: Feller
authors.forename: Hartmut
authors.initials: H
authors.lastname: Merz
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D001808:Blood Vessels / Q000473:pathology; D003937:Diagnosis, Differential; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D007694:Killer Cells, Natural / Q000473:pathology*; D016399:Lymphoma, T-Cell / Q000473:pathology*; D008297:Male; D009182:Mycosis Fungoides / Q000473:pathology*; D055611:Natural Killer T-Cells / Q000473:pathology*; D012878:Skin Neoplasms / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor