A subcutaneous tumour in a patient with rheumatoid arthritis.

A 79-year-old Caucasian woman with rheumatoid arthritis (RA) for 27 years presented with a swelling on her left wrist. Both pain and a tingling sensation in the radial four fingers could be elicited by applying light pressure on the swelling. The patient was uncertain as to the actual onset of this swelling and had not complained, as it resembled many of the swellings of the hand region she had previously experienced. Primarily, an organised tenosynovitis was suspected with a presumed pressure on the median nerve, and a puncture was considered. Ultrasonography diagnosed a large hypoechoic mass. This is not unusual with longstanding inflammatory changes, which may contain elements of connective tissue. Using the Doppler function it turned out to be highly vascularised. The tumour could not be removed, but histology revealed a diagnosis of schwannoma.