Leg ulcer and thigh telangiectasia associated with natural killer cell CD56– large granular lymphocyte leukemia in a patient with pseudo-Felty syndrome

Clonal disorders of large granular lymphocytes (LGL) represent a rare spectrum of biologically distinct lymphoproliferative diseases originating either from mature T cells or natural killer cells. Both subtypes can manifest as indolent or aggressive disorders. We report a 77-year-old woman with rheumatoid arthritis, splenomegaly, and neutropenia who developed a painful leg ulcer refractory to treatment and thigh telangiectatic lesions. Because of the association of rheumatoid arthritis, splenomegaly, and nonspecific neutropenia, the diagnosis of Felty syndrome was initially made. Further investigation allowed the diagnosis of a CD56– natural killer–cell LGL leukemia and documented skin infiltration by natural killer cells. Cutaneous manifestations of LGL leukemia have been rarely reported. This report of pseudo-Felty syndrome with CD56– LGL leukemia, presenting with a leg ulcer and telangiectasia, enhances the role of dermatology in the diagnosis of hematologic neoplasia.