We describe a patient who had multiple subcutaneous rheumatoid nodules associated with episodes of acute intermittent arthritis and subchondral cystic lesions of the small bones of the hands and feet; this coadition is termed "rheumatoid nodulosis. " The patient had a cystic lesion in communication with the joint cavity, rheumatoid granulomas, and evidence of a central zone of necrosis opening toward the joint space. His case is compared with 8 previously reported cases, and possible etiologies of the subchondral bone cyst formation in rheumatoid nodulosis are discussed.Subcutaneous rheumatoid nodules occur in 20-25% of patients with seropositive rheumatoid arthritis (RA) (l), and histologically identical subcutaneous nodules are seen in other diseases (2). Ginsberg et a1 (3) were the first to report a symptom complex, which they termed "rheumatoid nodulosis," in which subcutaneous rheumatoid nodules are associated with episodes of acute intermittent arthritis and subchondral cystic lesions of the small bones of the hands and feet. There are few histopathologic descriptions of these cysts ( 4 3 , and they are not always well docu- mented. For these reasons, their etiology and diagnostic significance remain unclear.The morphologic findings in the patient with rheumatoid nodulosis that are presented in this report might elucidate the origin and significance of subchondral bone cysts in this condition.Case report. At the age of 35, the patient had experienced episodes of intermittent arthritis in the metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joints and in the knees. The episodes remitted spontaneously without sequelae within 4-5 days and recurred at variable intervals ranging from 2-6 weeks. At that time he also experienced nontender nodular lesions localized in the hands, elbows, and feet, with no apparent changes in the overlying skin. Laboratory findings at that time included positive rheumatoid factor (RF), erythrocyte sedimentation rate (ESR) 25 mm/hour, and normal values for hemoglobin, white blood cell (WBC) count, and serum biochemical values including uric acid. A diagnosis of seropositive RA was made and the patient was begun on a regimen of nonsteroidal antiinflammatory drugs and gold salts. He discontinued the gold salts on his own initiative after 4 weeks. His condition remained the same for 12 months; thereafter, the joint symptoms disappeared, but the nodular lesions persisted.When he was referred to our unit in 1983, at the age of 44, the patient presented with intermittent arthralgia in the MCP and MTP joints and knees with morning stiffness lasting 2 hours. He denied having intestinal symptoms or renal lithiasis. He admitted to drinking 80 gm of alcohol/day. His family history was unremarkable.Physical examination revealed 19 nontender subcutaneous nodules, 0.5-2 cm in diameter, which