Chronic Urticaria Versus Dermatomyositis in a Case of T-Cell Large Granular Lymphocytic Leukemia

In 2021, a study was conducted to diagnose a complex case involving chronic urticaria and T-cell large granular lymphocytic leukemia (T-LGLL), a rare type of leukemia known to cause autoimmune diseases. The aim was to determine whether the muscle damage observed was due to dermatomyositis or T-LGLL. The diagnostic process involved MRI scans, muscle biopsies, transmission electron microscopy, and anti-CN1A antibody testing. The MRI revealed moderate fibroadipose substitution in many muscles and edema in others, with no involvement of the shoulder girdle and upper limbs. Histological examination of the muscle fibers showed an "inflammatory myopathy with isolated phagocytotic fibers." Inclusion-body myositis, which is associated with chronic T-LGLL, was ruled out. The study concluded that the chronic urticaria was an indication of an immunoproliferative disease, and the myositis was due to T-LGLL, not dermatomyositis.