Large granular lymphocyte leukemia: Case report of chronic neutropenia andrheumatoid arthritis-like symptoms in a child

Lymphoproliferative disorders of large granular lymphocytes (LGL) are heter ogeneous, with a clinical/pathologic spectrum ranging from a benign polyclo nal expansion to an aggressive clonal disease. Often these lymphoproliferat ive disorders are associated with autoimmune disease. The clonal form of th e disorder, LGL leukemia, typically occurs in older adults with a median ag e of 55 years at diagnosis. Pediatric cases are referred to in review artic les; however, no detailed reports of T-cell LGL leukemia in children exist. This report illustrates a case of a child who presented initially at age 2 and 1/2 years with psoriasis, juvenile rheumatoid arthritis-like symptoms, and neutropenia. Bone marrow examinations obtained throughout his course h ave demonstrated progressive hypercellularity with increased reticulin fibe rs and replacement of the normal marrow elements by lymphocytes, which were later identified as large granular lymphocytes. Further testing with immun ophenotyping by flow cytometry and T-cell receptor gene rearrangement studi es revealed a monoclonal proliferation of large granular lymphocytes and co nfirmed a diagnosis of LGL leukemia. Although rare, large granular lymphocy te leukemia should be included in the differential diagnosis of chronic neu tropenia in children.