A case of rice bodyformation in dorsum manus mass associated with rheumatoid arthritis

An 85-year-old woman was referred to our hospital with fever and polyarthralgia and was diagnosed as rheumatoid arthritis. She also complained of a subcutaneous mass on the dorsum of the left hand. The fever and the polyarthralgia were improved byoral administration of prednisolone and salazosulfapyridine, but the mass on the hand dorsum remained. When we performed a skin incision on the mass, a large number of rice bodies were found inside the tendon sheath. A histopathological analysis revealed a fibrotic fibrinoid structure in the center of the rice body, which was closely surrounded by histiocytic cells. Formation of rice bodies in the dorsum manus has rarely been reported in the literature.