Arthritis in acute leukemia. Clinical and histopathological observations.

Eight patients had acute leukemia and arthritis. In five the arthritis had no evident cause other than the leukemia, and three had crystal-induced arthritis. Effusions from both groups of patients were often inflammatory. The average synovial fluid leukocyte count from the five effusions attributed to leukemia was 8,790/cu mm. A synovial needle biopsy specimen from one of these patients showed acute and chronic inflammation but no leukemic infiltration. Bone involvement was suggested by bone pain in only one patient. In no case did arthritis persist in the presence of a hematologic remission. In the three patients with crystal-induced arthritis, the average synovial fluid leukocyte count was 13,000/cu mm. There were crystals of monosodium urate in one and of calcium pyrophosphate dihydrate in two patients. Suspected blast forms were seen in the synovial fluid of only one patient, one of those with pseudogout. Electron microscopic studies of needle biopsy specimens of synovial membrane from leukemic patients with arthritis described herein for the first time showed no blast forms, virus-like particles, or electron-dense deposits in vessel walls to suggest specific mechanisms for the arthritis.