[Sick sinus syndrome as an initial symptom of B-cell malignant lymphoma involving the heart].

We present a rare case of B-cell malignant lymphoma in whom lymphoma cell infiltration into heart caused sick sinus syndrome (S.S.S) as an initial symptom and premortem diagnosis of heart involvement was made. A 62-year-old woman was admitted to the orthopedic hospital because of pain in the lower extremities and discomfort in the chest. Chest roentgenogram showed an enlarged cardiac shadow and electrocardiogram (ECG) showed a sinus node dysfunction. A diagnosis of S.S.S. was made by the examination of sinus node recovery time. Myelography disclosed complete block between the 3rd and 4th lumbar vertebra. Pacemaker was inserted and laminectomy was done. The diagnosis of malignant lymphoma was made by the cytological study of the resected tissue. Gallium isotope study showed markedly increased isotope uptake in heart and abdomen. After chemotherapy the enlarged shadow of heart reduced in size and the uptake of gallium disappeared. ECG showed a sinus regular rhythm. Afterwards her general condition got worse and leukemic convergence of malignant lymphoma occurred. Monoclonal antibody study of these cells disclosed positive CD 19 (OK B1), CD 20 (OK B4), and surface IgM-lambda.