Axial (Fig. 1A) and coronal (Fig. 1B) abdominopelvic Computed Tomography (CT) after administration of contrast showed an exuberant distension of right iliopsoas bursa not in communication with the hip joint and an iliopsoas muscle distension by liquid (please see arrows). The ipsilateral hip joint has a small joint effusion. This case refers to a 74-year-old man with rheumatoid arthritis (RA) diagnosed 40 years ago and currently treated with tocilizumab. The patient had right hip joint pain, an inguinal mass and unilateral lower limb edema for 2 months. The analytic study was normal, including inflammatory parameters. Ultrasound-guided aspiration of the bursal liquid was performed, which revealed inflammatory characteristics. Its bacteriological and mycobacteriological exams, PCR for Mycobacterium tuberculosis and cytology for malignant cells were all negative. Whereby, oral steroidal therapy (10 mg/day prednisone, according to his low body mass index) was started and the lower limb edema gradually disappeared.
Iliopsoas bursitis is a rare clinical manifestation of RA and should be suspected in patients with a long history of disease presenting with persistent hip joint pain and an inguinal mass or unilateral lower limb edema. In this case, the edema of the lower limb was probably due to the fact that the enlarged iliopsoas bursa was associated with marked compression of the right common femoral vein. CT proved to be valuable in establishing the early diagnosis. Steroids treatment have demonstrated efficacy in managing this condition, though, when this intervention is ineffective bursectomy may be indicated. In this patient, the fact that the adjacent hip joint was not severely affected by arthritis and the lack of communication between the hip joint cavity and the iliopsoas bursa can be considered favourable prognostic factors. Thus, the case described emphasizes the importance of early detection of iliopsoas bursitis as a cause of hip joint pain in RA to avoid future complications resulting from compression of the adjacent structures.
