A 73-year-old woman presented with a recurrent cystic mass around her left olecranon. She had a history of 8 steroid injections due to elbow pain beginning 3 years ago and twice had undergone aspiration of olecranon bursitis that developed two months prior to presentation. She had been taking medications for hypertension and diabetes with no pertinent past history. On magnetic resonance imaging (MRI), there were multiple nodules in the olecranon bursa, which were isointense to muscle on T1-weighted images and hyperintense to muscle on T2-weighted images. Our initial diagnosis was synovial chondromatosis. On bursoscopy, masses of gray-white colored nodules were observed in the bursa. Finally, synovial chondromatosis and non-tuberculous mycobacterial infection were concurrently diagnosed. In conclusion, uncalcified synovial chondromatosis and rice bodies can have similar visual and MRI characteristics; therefore, we suggest that clinicians should be aware of the possibility of other infections in cases of this type.
Non-tuberculous mycobacterial olecranon bursitis has already been described in several reports [
A 73-year-old woman presented with a rapidly growing recurrent cystic mass around her left olecranon. She had a history of elbow pain and had received 8 steroid injections beginning approximately three years prior to presentation at our clinic. A cystic mass developed at the posterior aspect of the left elbow about two months prior to presentation. At a local clinic, the initial diagnosis was olecranon bursitis, and twice she had undergone aspiration for the effusion within the bursa. However, three weeks after the second aspiration, the cystic mass recurred and grew rapidly. As a result, she was referred to our clinic for further evaluation.
On physical examination, the mass size was approximately 20 cm long and 5 cm wide (
Although we initially considered recurrence of olecranon bursitis, because of a previous recurrence despite repeated aspirations over a two month period, ultrasonography was performed to determine whether other accompanying lesions were present. On ultrasonography, a mixed hypoechoic mass with a well-defined irregular shape was observed in the olecranon bursa. Subsequently, magnetic resonance imaging (MRI) was performed to discriminate the mixed hypoechoic mass.
On MRI, there were multiple nodules in the olecranon bursa, which were isointense to muscle on the T1-weighted images and hyperintense to muscle, though less intense than fluid, on the T2-weighted images. Following intravenous administration of gadolinium contrast, there was enhancement of the thin, smooth synovial membrane surrounding the olecranon bursa but no enhancement of the soft tissue nodules. The underlying bones appeared normal without joint involvement (
We considered the presence of secondary synovial chondromatosis of chronic olecranon bursitis and planned for bursoscopic synovectomy and mass excision. We performed debridement of the inflammatory and proliferated synovial tissue around the olecranon bursa and found masses of numerous gray-white colored nodules in the bursa (
Two weeks later, based on the histologic results, synovial chondromatosis was diagnosed. Subsequently, the nontuberculous mycobacterial result was positive on real-time PCR. On those bases, empirical antimicrobial agents (clarithromycin, rifampin, and ethambutol) were administered to the patient for first 3 months regardless of in vitro susceptibility drug test. Three months after the operation, tissue cultures revealed the presence of
Synovial chondromatosis is a rare, mostly benign proliferation of the synovium of the joint, tendon, or bursa, and can result in the formation of loose bodies. The intra-articular form most commonly affects the knee joint. Extra-articular sites are uncommon, most often involving synovial sheaths or bursa of the hand or foot [
Non-tuberculous mycobacteria are present in the soil and water and can cause extra-pulmonary disease under immunocompromised conditions. Garrigues et al. [
Rice body formation is most commonly observed in chronic rheumatoid arthritis, but may also occur in seronegative arthropathies and chronic low-grade synovial infections such as those that result from mycobacterial infection [
Unmineralized synovial chondromatosis on MRI shows isointense or slightly hyperintense signals compared to the signal intensity of skeletal muscle in T1-weighted sequences and a hyperintense signal in T2-weighted sequences. In mineralized synovial chondromatosis, both T1- and T2-weighted sequences show hypointense signals. Other authors, however, have reported that T2-weighted images of synovial chondromatosis can show nodular filling defects within the hyperintense synovium, even when the nodules are not calcified [
Recurrent
The specific antimycobacterial regimen depends upon the NTM species isolated and, for certain NTM species, depends on the results of in vitro susceptibility testing. It is important not to use antibacterial monotherapy since this can lead to the development of resistance. The duration of antimycobacterial therapy depends upon several factors, including the extent of disease, response to treatment, the causative species, and the immune status of the patient [
In conclusion, although synovial chondromatosis may occur in the olecranon bursa, to our knowledge, our case is the only one to have been reported. In addition, since uncalcified synovial chondromatosis and rice bodies may appear similar, both visually and on MRI, we suggest that clinicians should be aware of the possibility of other infections in cases of this type.
IRB approval: Kyungpook National University Hospital (No. KNUH 2018-06-030).
None.
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea, funded by the Ministry of Science, ICT and Future Planning (2015R1C1A1A02036478).
A large mass (about 20 cm long and 5 cm wide) originating from the olecranon bursa on the posterior aspect of the left elbow was identified.
Plain radiographs showing soft tissue enlargement around the olecranon with an olecranon process spur and calcification on triceps insertion but no evidence of arthritis, such as bone erosion, atrophy, or a destructive process.
(A) T1-weighted sagittal magnetic resonance imaging (MRI); There were multiple nodules inside the olecranon bursa, which were isointense to muscle. (B) T2-weighted sagittal MRI; hyperintense to muscle, though less intense than fluid. (C) Following intravenous administration of gadolinium contrast, there was enhancement of the thin, smooth synovial membrane surrounding the olecranon bursa, but no enhancement of the soft tissue nodules.
(A) Inflammatory and proliferated synovial tissue in the olecranon bursa. (B) A mass of gray-white colored nodules in the bursa.