From a small series of patients hospitalized with rheumatoid arthritis, six cases are presented in which Baker's cysts were associated with pain a n d swelling of the calf, initially erroneously diagnosed as thrombophlebitis. The pathogenesis of these calf symptoms is reviewed.
Ex u n pauco extense serie de casos d e patientes hospitalisate con arthritis rheumatoidee, sex es presentate in le quales cystes de Baker esseva associate
CQll dolores e tumescentia del sura, initialmente diagnosticate i n error como thrombophlebitis. Le pathogenese d e iste symptomas sural es revistate. HE APPEARANCE of pain, swelling, and tenderness in the calf, uni-T lateral ankle edema, and a positive Homans' sign calls for a presumptive diagnosis of venous thrombosis. Although arthritis at the knee and ankle may produce these signs and symptoms, there is usually no cause for confusion when swelling and tenderness are predominant in and around the joints. In patients with arthritis, however, swelling, erythema, tenderness and pain in the calf may appear, clearly separable from articular involvement. Our recent experience indicates that these symptoms are not uncommonly manifestations of a Baker's cyst rather than of phlebitis. In several instances, the cysts were elicited only after calf swelling and erythema subsided, or patients were properly positioned, standing with the knee in full extension.
MATERIAL AND METHODS
As an outcome of our experience in Case 1 with the combination of rheumatoid arthritia, a Baker's cyst, and suspected thrombophlebitis, 45 consecutive cases, beginning with Case 1, of definite or classical rheumatoid arthritis hospitalized at Ann Arbor Veterans Administration Hospital for various reasons during the period from November 1961 through December 1962 were screened for thrombophlebitis and Baker's cysts (table 1.).
Twelve patients had popliteal cysts, either demonstrable or well documented in previous records. Eight cases had had, at one time or another, a clinical diagnosis of thrombophlebitis in the lower leg; six of these were patients with Baker's cysts, whose histories are presented as follows: CASE 1 ( AAVAH, A-8584) The patient, W. W. D., a 45-year-old male with definite rheumatoid arthritis was admitted in November 1961, five months after the onset of polyarthritis. On admission numerous joints were involved including the left knee, which was the site of effusion, increased heat, and tenderness. There was no evidence of a Baker's cyst. On the 14th hospital day, pain, increased heat, swelling, and non-pitting edema with a positive Homans' sign appeared in the left calf. A diagnosis of thrombophlebitis was made and the patient was treated by elevation of the leg and hot soaks. After four days, pain, heat