Percentage of {Gamma}{Delta} T Cells in Panniculitis by Paraffin Immunohistochemical Analysis.

Cutaneous T-cell lymphomas with panniculitis-like histologic features have different clinical courses depending on whether they are composed of alphabeta T cells or gammadelta T cells, necessitating their distinction for proper prognostication. However, unlike alphabeta T cells, gammadelta T cells cannot be reliably detected in formalin-fixed, paraffin-embedded sections. We demonstrated that a commercially available antibody can detect gammadelta T cells and examined 2 cases of flow cytometry-proven gammadelta T-cell lymphomas and 15 control cases of nonneoplastic panniculitis. In both lymphomas, the atypical lymphocytes were gammadelta T cells, whereas the reactive lymphocytes were alphabeta T cells. In contrast, nonneoplastic panniculitis had predominantly alphabeta T cells with many fewer and individually scattered gammadelta T cells. The detection of gammadelta T cells in paraffin sections provides a powerful new tool to characterize T cells in lymphomas and inflammation

Large Natural Killer Cell Lymphoma Arising From An Indolent Natural Killer Cell Large Granular Lymphocyte Proliferation.

Natural killer cell large granular lymphocyte proliferation is a relatively rare disorder that typically runs a chronic, indolent course. We present a patient with a 3 1/2-year history of natural killer cell large granular lymphocyte proliferation terminating in large cell lymphoma with natural killer cell features. The diagnosis of natural killer cell large granular lymphocyte proliferation was based on flow cytometric demonstration of an expanded population of CD3- CD16+/CD56+ lymphocytes in the peripheral blood. The patient experienced various rheumatologic symptoms, but was hematologically stable for 3 1/2 years. He then developed fevers, night sweats, weight loss, and a left lower lobe lung mass. Resection of the mass showed a large cell lymphoma with immunohistochemical positivity for CD2, CD7, CD56, and T-cell intracellular antigen-1, compatible with natural killer cell origin. In situ hybridization for Epstein-Barr virus and polymerase chain reaction analysis for T-cell receptor gene rearrangement were negative. To our knowledge, this is the second documented report of chronic natural killer cell large granular lymphocyte proliferation terminating in an aggressive large natural killer cell lymphoma