Large benign rheumatoid nodules of the trunk in an elderly patient: radiologic appearance mimicking a soft-tissue sarcoma

An 80-year-old woman without any evidence of rheumatoid arthritis presented with two large (maximum diameter: 6 cm and 7 cm), rapidly growing, rubbery nodules on the trunk. Although the clinical and radiological appearance suggested malignancy, the nodules were pathologically identical to rheumatoid nodules in rheumatoid arthritis, and the nodules regressed spontaneously. The final diagnosis was benign rheumatoid nodules. Recognition of this rare clinical entity is important to avoid unnecessary examination and treatment.