Pseudocyst of the auricle was first reported by Hartmann in 1846 and first described in the English literature in 1966 by Engel.[1] Historically, pseudocyst of the auricle has been addressed by many terms, including endochondral pseudocyst, intracartilaginous cyst, cystic chondromalacia, and benign idiopathic cystic chondromalacia. Because the condition is uncommon, it may be misdiagnosed or underreported by clinicians. Pseudocyst of the auricle is characterized as a benign, noninflammatory swelling to the ear, located on either the front or side surface.[2, 3]
The etiology of pseudocyst of the auricle is unknown, but several pathogenic mechanisms have been proposed.
Originally, Engel postulated that lysosomal enzymes might be released from chondrocytes and cause damage to the auricular cartilage. However, analysis of pseudocyst contents revealed a fluid rich in albumin and acid proteoglycans, with a rich cytokine milieu but lacking in lysosomal enzymes.
Analysis of the cytokine profile of the fluid indicates markedly elevated levels of interleukin (IL)–6, which is believed to stimulate chondrocyte proliferation. IL-1, an important mediator of inflammation and cartilage destruction, induces IL-6. IL-1 also stimulates chondrocytes to synthesize proteases and prostaglandin E2 while inhibiting the formation of extracellular matrix components.
Others have suggested that a defect in auricular embryogenesis contributes to pseudocyst formation. This defect causes the formation of residual tissue planes within the auricular cartilage. When subjected to repeated minor trauma or mechanical stress, these tissue planes may reopen, forming a pseudocyst.
Pseudocysts usually present spontaneously or following repeated minor trauma.[2] The observation that an auricular pseudocyst often results after repeated minor trauma, such as rubbing, minor sport injuries, ear pulling, sleeping on hard pillows, or wearing a motorcycle helmet or earphones, has led to the suggestion that these minor traumas may be the mechanism. In support of this traumatic etiology, elevated serum lactic dehydrogenase (LDH) values have been reported within the pseudocyst fluid.[4, 5] Two of the elevated isoenzymes, LDH-4 and LDH-5, are proposed as major components of human auricular cartilage. These enzymes may be released from auricular cartilage degenerated from repeated minor trauma.
One article reports that pseudocysts can be regarded as simply a variation of othematoma or otoseroma.[6]
The etiology for pseudocysts of the auricle is unknown, but several pathogenic mechanisms have been proposed, including chronic low-grade trauma and spontaneous development.[7] Some have suggested that a minor defect in auricular embryogenesis can also contribute to pseudocyst formation. This defect may cause the formation of residual tissue planes within the auricular cartilage. When subjected to repeated minor trauma or mechanical stress, these tissue planes may open, forming a pseudocyst. The auricular cartilage in particular may be more susceptible to traumatic insult because of its lack of connective tissue overlying the cartilage with firm adherence to the skin.[8]
Consistent with the proposed mechanism, atopic dermatitis with accompanying facial and ear involvement may be a predisposing condition for pseudocyst formation.[9, 10] Although the incidence of pseudocysts in patients with atopic dermatitis appears to be low, these patients have an earlier occurrence of the condition and a greater incidence of bilateral lesions compared with the general population.
Pseudocyst has also been reported in a patient with intense pruritus who was later diagnosed with lymphoma.[11] After chemotherapy for the lymphoma, the pruritus improved with spontaneous reduction in the volume of the pseudocyst. The authors proposed that the trauma from scratching and rubbing of the ears was the major exacerbating cause of the pseudocyst.
Furthermore, pseudocysts have presented as a rare result following a relapse of polychondritis. Polychondritis is an uncommon autoimmune disorder associated with cartilaginous tissues on the nose and ear. The specific occurrence of auricle pseudocysts is very uncommon.[12]
Tan and Hsu reported the epidemiological features, clinicopathologic characteristics, and success of surgical treatment in 40 patients of different Asian groups presenting with pseudocyst of the auricle.[13] Results showed a Chinese predominance (90%), followed by Malays (5%), and Eurasians (5%). All except one patient had unilateral presentations. Most (55%) presented within 2 weeks of auricular swelling. Few (10%) had a history of trauma.
Most reports of pseudocyst of the auricle have involved Chinese or white patients; however, persons of all racial groups have been affected.
Males show a higher prevalence of pseudocyst of the auricle than females.[14]
Most pseudocysts of the auricle are unilateral and occur in men aged 30-40 years, but lesions are documented in patients ranging in age from 15-85 years of both sexes.
Without treatment of pseudocyst of the auricle, permanent deformity of the auricle may occur.
Patients with pseudocyst of the auricle should be informed that even with optimal therapy, recurrence is common. Avoidance of triggers or exacerbating factors should be encouraged.
A pseudocyst manifests as a painless swelling on the lateral or anterior surface of the pinna, developing over a period of 4-12 weeks. The pseudocyst may appear randomly or after repeated minor trauma.[12] Frequent traumas that may accompany the clinical history include rubbing, ear pulling, sleeping on hard pillows, minor sports injuries, or wearing of a motorcycle helmet or earphones. Neurological diseases have also been shown to promote the occurrence of pseudocysts of the auricle.[2] It has also been associated with cases of pruritic skin or systemic diseases, including atopic dermatitis and lymphomas.[9, 11]
Physical examination findings include swelling and tenderness of the lateral and/or anterior part of the ear.[2] A pseudocyst is a noninflammatory, asymptomatic swelling on the lateral or anterior surface of the pinna, usually in the scaphoid or triangular fossa. They range from 1-5 cm in diameter and contain clear or yellowish viscous fluid, with a consistency similar to that of olive oil. Note the image below.
 View Image | Asymptomatic nodule on the left ear. |
In several reports, magnetic resonance images revealed a serous fluid collection within the auricular cartilage, further enhancing the diagnosis.[11, 15]
Histologically, pseudocysts of the auricle lack pathognomonic features, but they can typically be characterized by an intracartilaginous cavity lacking an epithelial lining. They contain thinned cartilage and hyalinizing degeneration along the internal border of the cystic space. The epidermis and dermis overlying the pseudocyst are usually normal. However, a dermal perivascular lymphocytic infiltrate is commonly found, along with inflammatory cells within the cystic space.
In one of study, calcification of the auricular cartilage was identified at least 7 days after initial clinical presentation.[16] Although contrary to literature reports,[8, 17, 18] one study postulated that an inflammatory response is crucial to the development of pseudocysts. This theory is based on a consistent perivascular inflammatory response seen in all 16 specimens studied.[16] Eosinophilic degeneration and necrosis of the cartilage is also present in some areas.[15] Intracartilaginous fibrosis and granulation tissues are manifestations of later stages of pseudocysts.[16] A slide of an auricular pseudocyst is shown below.
View Image | Low magnification of this pseudocyst reveals a mucin-containing cystic cavity. |
The goals of treatment of pseudocyst of the auricle are preservation of anatomical architecture and prevention of recurrence.[19, 20] Without treatment, permanent deformity of the auricle may occur. Treatment options include needle aspiration with pressure dressings, medication (either systemic or oral), and surgical care. Consensus on the best management for pseudocyst of the auricle is undetermined, and a combination of treatment modalities may be necessary to achieve optimal resolution.
No medical treatment is uniformly effective for pseudocyst of the auricle. High-dose oral corticosteroids and intralesional corticosteroids therapies have been reported, with variable results.[8, 21] Some authors argue against the use of intralesional steroids, implicating them in permanent deformity of the ear, while others support steroid injection therapy or even oral steroid therapy.[22] Advocates of steroid injection therapy consider it a much simpler procedure than surgery. Kim et al report intralesional steroid therapy in combination with a clip compression dressing.[23] Patigaroo et al found that simple observation as a treatment option was found to be as good as intralesional steroids.[24]
Simple needle aspiration of pseudocyst fluid followed by placement of a compressive dressing is one of the most commonly performed methods. However, without use of a pressure dressing, recurrence is common. In one study, the mean time of recurrence of the pseudocyst after aspiration (without subsequent pressure dressing) was 2.3 days.[25] Patigaroo et al used the commonly used technique of simple aspiration followed by intralesional steroid injection followed by pressure dressing. Their success rate was 57% with minimal complications, including thickening of the pinna.[24, 26]
Some have used an auricular prosthesis formulated with the creation of a moulage fitted to the ear by the prosthetist for pressure.[27] Several reports describe a combined procedure using surgical incision and drainage of the lesion, replacement of the anterior skin surface, and the application of a pressure dressing or bolster.[24, 25]
Surgical curettage and fibrin sealant has been shown to be effective in obliterating the cystic cavity. The fibrin sealant works as a template for fibroblasts to move through the wound and serves as a delivery system for growth factor. It also has hemostatic and antibacterial activity.[15]
Intralesional injections of minocycline hydrochloride (1 mg/mL) 2-3 times at 2-week intervals has shown efficacy. Minocycline is thought to work as a sclerosant through its anti-inflammatory and immunomodulatory mechanisms.[28] Other sclerosants used include 1% trichloroacetic acid[29] and tincture of iodine.
An alternative to steroids and conventional surgical incision is a simple punch biopsy followed by the application of a bolster for approximately 2 weeks. This method should be a welcome alternative for physicians who choose to not use steroids.[30] This simple alternative method provides a safe and effective mechanism for diagnosis and treatment of this phenomenon, while minimizing the risk of deformity. Successful treatment of an auricular pseudocyst using a surgical bolster is reported in the literature.[31, 32] Shan et al reported success with surgical treatment using plastic sheet compression.[33]
One study reported a patient who developed initial perichondritis following excision, requiring treatment with intravenous antibiotics. The perichondritis resolved, but with a resultant cauliflower ear 3 months after the surgery. Authors proposed that since the patient was an elderly woman with diabetes mellitus, the underlying comorbidity may have contributed to the unfavorable outcome.[25]
One report stated the potential risk associated with compressive techniques, such as a compressive ear splint for pressure application, may include pressure necrosis if the device is too tight. Proper application and instructing the patient to remove the device and examine for redness of the ear several times daily will aid in prevention.[27]
Asymptomatic nodule on the left ear.
Low magnification of this pseudocyst reveals a mucin-containing cystic cavity.
Asymptomatic nodule on the left ear.
Low magnification of this pseudocyst reveals a mucin-containing cystic cavity.
Pseudocyst of the auricle Chondrodermatitis chronica helices Relapsing polychondritis Subperichondrial hematoma Swelling Localized Localized Diffuse Localized Skin involvement Rare Yes, crusting/ulceration Yes, erythematous Rare Pain Rare Common (from ulceration) Common (extremely tender) Common Systemic Symptoms No No Yes (involvement of other cartilage) No Histology Intracartilaginous, cystic defect, granulation tissue Subperichondrial granulation tissue, cystic dilatation rare Acute inflammable cells seen; antibody deposition on basement membrane during immunofluorescence Inflammatory cells with degraded blood products Adapted from Lim CM, et al. “Pseudocyst of the Auricle.” 2002.
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