Image Quiz

A Thirty-eight-Year-Old Man with Painful Lesions About the Elbow (continued)

Answer: Tophaceous gout

For larger view, click on image
Fig. 4	Fig. 5	Fig. 6
Fig. 4 Amorphous material surrounded by histiocytic inflammatory and fibrous tissue reaction. Foreign-body giant cells (fused histiocytes) can be seen at the perimeter of the tophus (arrows) (hematoxylin and eosin, original magnification, ×100). Fig. 5 Needle-like crystals (hematoxylin and eosin section, unpolarized, original magnification, ×400). Fig. 6 Crystals demonstrating negative birefringence (compensated polarized light, original magnification, ×400).

The patient subsequently underwent excision of the two gouty tophi masses in the ulnar aspect of the forearm. Appropriate medications for hyperuricemia were prescribed in consultation with a rheumatologist, and dietary recommendations were made prior to discharge.

Discussion

Gout, also known as monosodium urate crystal deposition disease, is a common disorder affecting nearly two million men and women in the United States alone¹. It predominantly affects men older than thirty years of age and postmenopausal women². Gout is the clinical syndrome associated with hyperuricemia (high serum urate levels) and is characterized by an accumulation of urate in the extracellular space. Physiological conditions may contribute to this accumulation, which is also associated with dietary factors, diuretic use, weight gain, and obesity^1,2. However, only a limited number of patients with hyperuricemia actually have gout, a condition in which the excess urate forms needle-like crystals in the tissue³.

The most common site of the initial presentation of tophaceous gout is the first metatarsophalangeal joint, but it is often seen in many joints, especially those of the lower extremities⁴. The clinical presentation of gout can include periodic attacks of acute inflammatory arthritis, the development of tophaceous deposits, and the formation of renal uric-acid stones³. The three main stages of gout are acute gouty arthritis, intercritical gout, and chronic tophaceous gout³.

Acute gouty arthritis is characterized by abrupt attacks of joint inflammation. These attacks are generally monoarticular and are more common in the lower extremities. The onset is usually rapid and is typically precipitated by events such as trauma or the ingestion of seafood, red meat, or alcohol³.

Chronic tophaceous gout will eventually develop in a subset of patients with gout. This condition is characterized by the formation of tophus masses most commonly found in the kidneys and in subcutaneous and periarticular areas^3,5. Frequently, affected sites include the fingers and toes⁶, the wrist, the ankle, the knee, the Achilles tendon, and the patella. The tendons and bursa that surround the joints are often involved. Although rare, tophi can also form in the abdomen, the pelvis, and the heart^6,7.

Tophus deposits consist of macrophages, debris, and monosodium urate crystals surrounded by dense connective tissue^4,8. There can be associated bone and cartilage erosions in the adjacent areas^4,5. Magnetic resonance imaging of gouty tophi tend to show "low to intermediate signal intensity on T1 and T2" weighted images⁹. Some enhancement may be seen with the use of contrast, although this result is not consistent.

Histologic examination of tophi typically reveals collections of amorphous and crystalline material surrounded by a prominent histiocytic reaction¹⁰. The crystals viewed under compensated polarized light will demonstrate negative birefringence, a characteristic feature of sodium urate. However, urate crystals are difficult to demonstrate in histologic sections due to fixation with aqueous formalin, which often dissolves the soluble crystals out of the tissue. Fixation using only nonaqueous 100% ethanol, or direct microscopic examination of unfixed deposits, improves crystal identification¹.

Management of hyperuricemia includes modification of diet and lifestyle to lower the serum urate levels¹¹. These measures can also be used in the treatment of gout, although acute attacks may require the use of antiinflammatory (corticosteroid and nonsteroidal) and pain medications¹¹. Medications to lower serum urate levels can be beneficial, and the use of these drugs has reduced the number of patients who progress to chronic tophaceous gout.

In patients who have chronic tophaceous gout, surgical removal of the tophi may be necessary. The conventional treatment of tophi involves curettage and débridement, although this can be complicated by the size of the tophus, by local ischemia, or by wound infection¹⁰.

*The authors did not receive grants or outside funding in support of their research for or preparation of this manuscript. They did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.

References

1. Kramer HM, Curhan G. The association between gout and nephrolithiasis: the National Health and Nutrition Examination Survey III, 1988-1994. Am J Kidney Dis. 2002;40:37-42.
2. Choi HK, Curhan G. Gout: epidemiology and lifestyle choices. Curr Opin Rheumatol. 2005;17:341-5.
3. Bullough PG. Orthopaedic pathology. 4th ed. New York: Mosby; 2004. p 299.
4. Zaloga B, Hughes JL, Hoda RS. Pathologic quiz case: a soft tissue mass with bone destruction. Gouty tophus. Arch Pathol Lab Med. 2002;126:621-2.
5. Dalbeth N, Haskard DO. Mechanisms of inflammation in gout. Rheumatology. (Oxford), 2005;44:1090-6.
6. Chen CH, Chen CK, Yeh LR, Pan HB, Yang CF. Intra-abdominal gout mimicking pelvic abscess. Skeletal Radiol. 2005;34:229-33.
7. Iacobellis G, Iacobellis G. A rare and asymptomatic case of mitral valve tophus associated with severe gouty tophaceous arthritis. J Endocrinol Invest. 2004;27:965-6.
8. Palmer DG, Highton J, Hessian PA. Development of the gout tophus. An hypothesis. Am J Clin Pathol. 1989;91:190-5.
9. Gerster JC, Landry M, Dufresne L, Meuwly JY. Imaging of tophaceous gout: computed tomography provides specific images compared with magnetic resonance imaging and ultrasonography. Ann Rheum Dis. 2002;61:52-4.
10. Harris MD, Siegel LB, Alloway JA. Gout and hyperuricemia. Am Fam Physician. 1999;59:925-34.
11. Lee SS, Lin SD, Lai CS, Lin TM, Chang KP, Yang YL. The soft-tissue shaving procedure for deformity management of chronic tophaceous gout. Ann Plast Surg. 2003;51:372-5.