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Tophus due to gout is most commonly found in the toes and ankles, but can also be found in the auricle. Although small nodules on the helix are sometimes found in gout patients, a large mass lesion on the back side of the auricle is rare. We report a patient who visited the otology clinic due to an auricular mass lesion, which was diagnosed as a large auricular tophus. A 17- year-old male patient who suffered from gout complained of a right side auricular mass. A 3 cm sized solid mass lesion was detected on the back side of the right canvum conchal cartilage. The mass was soft, non-tender, and well-circumscribed. The lesion was first found 1-2 years earlier. The size of the lesion had been slowly increasing, but had recently stopped growing. The mass was surgically removed for pathologic confirmation and cosmetic reasons. Specimens were composed of 2 irregularly shaped pieces of soft-gray tan and yellowish tissue. The upper larger tophus was attached to the cartilage and the lower smaller tophus was embedded inside the auricular cartilage. Pathologic findings suggested tophus with amorphous deposits and subepithelial tissue.


Introduction Gout is a disease in which uric acid crystals are deposited in the body due to a high level of uric acid in the blood. Sometimes it was called as the king's disease, because it was usually found in rich and obese people; however, due to high-nutrition diets, gout is now frequently diagnosed in middle-aged men.1) Also, rapid aging is presumed to be a precipitating factor for the recent high incidence of gout, and the incidence of gout in the head and neck region is presumed to increase in the future due to similar reasons.1)Gout tophi are the end product of long standing high blood uric acid levels. The incidence of tophi is positively correlated with the level of blood uric acid and the duration of gout. The saturating concentration of uric acid in blood at normal body temperature is -7 mg/dL, and if the blood uric acid level is higher than this level, uric acid crystals start to precipitate in the body. It takes -10 years for a gout patient to experience tophi formation. The early stages of gout usually present as an single joint arthritis, but after 20 years, gout tophi can be found in multiple parts of the body in 25% of the patients.2) The most common sites of tophi formation are the fingers, toes, ankles, and knees. However, there are not many reports of a tophus being formed on the auricle and middle ear.4) Auricular tophus can usually be found around the helix, presenting as multiple small nodules. Because they are not related to loss of ear function, both patients and clinicians are not very interested in this condition and tend to ignore it. However, a large auricle mass must be differentiated from other tumorous conditions including malignancy. In this article, we report a patent who had a 3 cm sized mass on the back side of the auricle. We completely removed the mass for pathologic evaluation and it was diagnosed as a large tophus of the auricle. A detailed description of the patient and a review of literature are provided. Case Report A 17-year-old male visited the otologic clinic due to an auricular mass on the right side, which was first detected 1-2 years earlier. The mass was initially small, but tended to grow progressively larger, and had recently stopped growing. The mass was soft, non-tender, well-circumscribed, and was -3 cm in size. It was located on the posterior side of the auricle, was oval shaped, and longer in the vertical direction. The mass was fixed to the auricular cartilage. It was completely covered with normal looking healthy skin and there was no pain or tenderness. It was presumed that the mass was composed of 2 parts; an upper, larger (2 cm) mass and a lower, smaller (1 cm) mass (Fig. 1). The patient had no history of auricular injury. He had been diagnosed as gout at our hospital rheumatology clinic 5 years earlier and was currently taking medication for gout. He also had a history of surgical debridement with lavage of the metatarsophalangeal joint due to toe tophus. His blood uric acid level was 17.2 mg/dL, but after strict diet control, it had recently decreased to 10.0 mg/dL. We counseled the patient on the advantages and disadvantages of surgical removal of the auricular mass. After careful consideration, an excisional biopsy under local anesthesia was planned for cosmetic and diagnostic purposes. A 4 cm sized skin incision was made on the posterior surface of the auricle. The skin flap was elevated from a lateral to medial direction and the mass was dissected from the skin flap without difficulty. The solid, yellowish, and hard mass was composed of 2 separate parts. The upper mass was larger and was attached to the posterior surface of the auricular cartilage (Fig. 2). The upper mass was completely removed and a small portion of the normal auricular cartilage was also removed due to severe adhesion. The lower mass, which was smaller, was buried inside the auricular cartilage. The cartilage covering the posterior portion of the mass was removed together with the lower mass. The skin flap was repositioned and sutured. A compressive dressing was applied to avoid fluid collection between the skin flap and auricular cartilage. Pathologic examination showed the mass to have amorphous deposits and subepithelial tissue. Needle-like deposits with multifocal dystrophic calcification were also displaced within the stroma. These findings were consistent with gout tophus (Fig. 3). The patient was followed up for 2 months and there was no evidence of recurrence during this period. Discussion It is relatively common to find small multiple nodules of tophi around the helix; however, an auricular tophus arising in the auricle rather than the helix is seldom reported. There has been a case report on middle ear tophus3) and another article has reported a case of auricular tophus arising on the helix and antihelix. In some cases, the auricular tophus was the first symptom of gout in the patient. The authors have advocated that the possibility of gout tophus should be considered in patients presenting with an auricular mass, even if the patient has no history of gout.3)When an auricular mass is detected, various causes including sebaceous cyst, keloid, chondrodermatitis, leprosy, leishmaniasis, hemangioma, keratoacanthoma, chondroma, lipoma, schwannoma, actinic keratosis, basal cell carcinoma, Kaposi sarcoma, melanoma, dernoid, epidermoid, elastotic nodule, and a gouty node can be suspected. It is recommended to rule out the possibility of malignancy by pathologic verification.3) In this particular patient, we were able to suspect the possibility of tophus from the beginning, because the patient had a long standing history of gout; however, the mass was atypically large for a tophus and the location was also atypical. The auricular mass was found only on the right ear and the left auricle was free of any mass. It has been known that bilateral auricle tophi are more frequent than a unilateral auricular tophus. A unilateral auricular mass presenting in an atypical location and with this size required pathologic confirmation of the initial diagnosis.3)Most patients with tophus usually have a long history of gout, and it is not difficult to consider the possibility of tophus in such cases. However, in some patients, auricle tophus may be the first and only symptom of gout. Because it may be difficult to suspect the possibility of tophus in these cases, tophus should be kept in mind for differential diagnosis.3,4)Tophus in the joint may lead to arthritis, infection, nerve compression, or restriction of movement. In such cases, surgical debridement with lavage may be indicated to relieve pain or improve cosmetic and functional outcome.5) A case of auricular tophus is usually followed up on a regular basis without surgical intervention, because there are no symptoms or functional deficit. However, superficial tophus may be accompanied by skin inflammation or ulceration, resulting in severe pain. In our patient, there was no sign of inflammation or infection, but the diagnosis was not certain, and the patient wanted to remove the mass due to cosmetic problems. In the clinician's point of view, excisional biopsy may not only guarantee a good cosmetic outcome, but also an accurate diagnosis, preventing the possibility of misdiagnosis. Long standing elevation of blood uric acid levels and supersaturation are related to uric acid crystal precipitation and deposition in the joints. The saturating concentration of uric acid is 7 mg/dL when the temperature is 37℃. However, when the temperature decreases, the saturating concentration also significantly decreases. Peripheral areas such as toes or ankles are suspected to be the most frequent locations of tophi formation due to their lower temperatures compared to the central body temperature.2) Although the mechanism of tophus formation on the auricle has not been extensively studied, a similar explanation may be applied. The auricle is one of the body parts with the lowest temperature, and uric acid dissolved in blood may precipitate in the auricle due to the low saturating concentration. Another hypothesis is that the auricular cartilage may be a disposing factor for easy tophus formation, similar to the cartilage of joints.6)We described a patient with a large unilateral auricular tophus. This case suggests that the possibility of a gout tophus should be considered when dealing with a patient with an auricular mass lesion. REFERENCES: 1.Song JS. Light and shadow in the treatment of gout. J Korean Rheum Assoc 2010;17:227-9. 2.Lee KH, Lee SK. Pathophysiology of gout. Korean J Med 2011;80:251-4. 3.Griffin GR, Munns J, Fullen D, Moyer JS. Auricular tophi as the initial presentation of gout. Otolaryngol Head Neck Surg 2009;141:153-4. 4.Reineke U, Ebmeyer J, Schütte F, Upile T, Sudhoff HH. Tophaceous gout of the middle ear. Otol Neurotol 2009;30:127-8. 5.Jung YO. Management of complicated gout. Korean J Med 2011;80:269-72. 6.Filippucci E, Riveros MG, Georgescu D, Salaffi F, Grassi W. Hyaline cartilage involvement in patients with gout and calcium pyrophosphate deposition disease. An ultrasound study. Osteoarthritis Cartilage 2009;17:178-81.