Age / Sex : 63 / F

Chief complaint: volar and dorsal lump in right hand (o: 5yr), recent finger extension difficulty

What is your impression?

Two weeks later, you can see the final diagnosis with a brief discussion of this case.

(답안은 한 개만 보내주시기 바랍니다)

Courtesy: 안경식(Kyung Sik Ahn), 고려대학교 안암병원 (Korea University Anam Hospital)

Dialysis-related amyloidosis

Discussion

Findings:

Radiograph reveals soft tissue swelling around the right wrist and hand.

CT scan shows erosion of the carpal bone.

Transverse ultrasonography images obtained over the dorsal wrist reveals tendon thickening and echogenic materials in the tendon sheath.

MRI shows diffuse thickening of the flexor and extensor tendons. Non-enhancing peritendinous and intraarticular T2 and T1 low signal intensities are seen. The carpal tunnel is markedly swollen.

Differential Diagnosis: Inflammatory arthritis, gout, tenosynovial giant cell tumor

Diagnosis: Amyloidosis

Discussion:

Dialysis-related amyloidosis occurs secondarily to the deposition of β2-microglobulin, which is not filtered by the standard dialysis membranes. Dialysis-related amyloidosis predominantly involves the osteoarticular system and is clinically manifested by erosive and destructive osteoarthropathies, destructive spondyloarthropathy, and carpal tunnel syndrome.

On conventional radiographs, bone lesions of amyloidosis show radiolucencies of variable size within the medullary or cortical bone that may cause cortical destruction. Sonography exhibits thickening of the tendons and amyloid deposits in the area of the synovial membranes. MRI allows assessment of intraosseous, periarticular, and soft-tissue involvement. In most patients, bone lesions show decreased signal intensity on T1-weighted images and various signal intensity on T2-weighted images. Identification of an intraosseous lesion with relatively low signal intensity on both T1- and T2-weighted images is helpful in the diagnosis of amyloidosis. Synovial thickening can also be identified.

 Dialysis-related amyloidosis is characterized by various imaging appearances. In patients undergoing long-term hemodialysis, cystic and destructive lesions on conventional radiographs, echogenic soft-tissue abnormalities in intra- or periarticular structures, and relatively low-signal-intensity masses on T2weighted MR images should raise the suspicion of dialysis-related amyloidosis.

References:

Kiss E, Keusch G, Zanetti M, et al. Dialysis-related amyloidosis revisited. AJR Am J Roentgenol 2005;185(6):1460-1467.