PATHOLOGY CLINIC

Gout

Mon ica Hollowell, MD; Lester D. R. Thompson, MD, FASCP; Liron Pantanowitz, MD

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>' · tt ... \\ \\ ~ . ~ Figure 1. A: Urate isseenasstronglynegative, birefringent, needle- Figure 2: A: Amorphous fibrillary crystalline tissue deposits of shaped crystals under polarized light. B: Sheaves of elongated tophaceous goutinformalin-fixedtissue represent theproteinaceous monosodium uratecrystals arevisible in alcoholfixed and stained matrix thatsurroundsdissolvedcrystals (H&E).B:Agranulomatous with methyleneblue. reaction palisades around a gouty tophus(H&E).

Gout is caused by disord ered purine metabolism leads to long-term crystal deposition, usually in cooler resulting in . Symptoms are related to body sites around and cartilage; the accumula• the precipitation of monosodium ur ate () tion of these crystals results in pathognom onic tophi, crystals, typically in spaces or soft tissue. Primary or chalky deposits. gout is caused by an increase in ur ic acid production, In the head and neck region, gout may involve the while secondary gout is caused by either a decrease in auricle, larynx and, infrequently, the temp oroman• urinary uric acid excretion or an 'overproduction of dibul ar joint. Gouty tophi involving the external ear purine secondary to increased cell turnover (e.g., t u• may occur in the helix and antihelix, presenting as firm mor lysis). Predisposing clinical factors include older nodules that may ulcerate. When the cricoarytenoid age (fifth and older decade), male sex, obesity, heavy joint, vocal fold, or infraglottis is involved, gouty tophi alcohol ingestion, a purine-rich diet, certain medica• can present as an exophytic papillary lesion and mimic tions (e.g., thiazide diuretics), and genetic factors. carcinoma. They can also present as small, grainy mu• Patients with gout may present with episodes of cosal lesions. Cricoarytenoid joint involvement can acute arthr itis that are initiated by the crystallization lead to hoarseness, pain, dysphagia, and vocal fold fix• of urate within acutely inflamed synovial tissue. The ation. When the larynx is involved, pat ients generally first toe is the most commonly involved joint (gouty have severe multifocal disease. pain in the great toe is called podagra). Chronic gout On gross pathologic examination, tophaceous gout

From the Depar tm ent of Pathology, Baystate Medical Center, Tufts University School of Medicine, Springfield, Mass. (Dr. Hollowell and Dr. Pan• tanowitz), and the Department of Pathology, Woodland Hills Medical Center, South ern Californ ia Permanente Medical Group, Woodland Hills, Calif. (Dr. Thompson).

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PATHOLOG Y CLINIC

deposits appear as yellow-white chalky material. Urate granulomatous inflammation with foreign-body giant within aspirated or scraped material is seen as strongly cells (figure 2, B) and a lymphoplasmacytic infiltrate. negative, birefringent, needle-shaped crystals under Such a reaction can mimic a rheumatoid nodule. Large polarized light (figure I, A) or alcohol-fixed, methyl• tophi may undergo ossification. ene-blue-stained (figure I, B). In pseud ogout (deposi• Renal failure is responsible for death in up to 20% of tion of calcium pyrophosphate), the crystals are rhom• patients with gout. Treatment for acute gout includes boid. Histologically, gout y tophi appear as amorphous colchicine and nonsteroidal anti-inflammatory drugs. amphophilic material similar to amyloid deposits Avoidance of alcohol and purine-rich foods, combined (fig ure 2, A). The crystals within these tissue deposits with allopurinol or probenecid pharmacotherapy, can are difficult to visualize with routine fixation, tissue help in managing chronic hyperuricemia. processing, and staining because they are dissolved by aqueous solutions during formalin proces sing. There• Suggested reading fore, tissue submitted to the pathology laboratory for Adair C. Non-neoplastic lesions of the ear and temporal bone . In: Thomp son LOR, ed. Head and Neck Pathology. Philadelphia: the identification of uric acid crystals should include a Elsevier Health Sciences; 2006:371-96. scrape (smeared onto an unfixed slide) and/ or alcohol• Guttenplan MD, Hendrix RA, Townsend MI, Balsara G. Laryngeal fixed material (figure 1) in addition to a form alin-fixed manifestations of gout. Ann Otol Rhino l Laryngol 1991;100(11): 899-902. specimen. Often the urate crystals are sur rounded by

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134· www.entjournat.cem ENT-Ear, Nose &Throat Journal s March 2008