Nodule on scaphoid fossa of the ear

A pseudocyst of the auricle (PCA), less commonly known as benign idiopathic cystic chondromalacia, presents as a benign asymptomatic swelling of the pinna, usually localized to the scaphoid or triangular fossa. The lesions typically develop over a course of 1...

Submit your diagnosis to see full explanation.

A pseudocyst of the auricle (PCA), less commonly known as benign idiopathic cystic chondromalacia, presents as a benign asymptomatic swelling of the pinna, usually localized to the scaphoid or triangular fossa. The lesions typically develop over a course of 1 to 3 months.

The swelling may appear as several distinct smaller nodules, or it may present as a single larger nodule that is up to 5 cm in size. As in this case, incision of the lesion will find clear or yellowish viscous fluid with a consistency that is similar to that of olive oil.¹


Most patients report that the lesions are asymptomatic, and they present for treatment concerned about the nature and cosmetic appearance of the lesions.


Although the exact cause of PCA is unknown, several theories have been introduced. One author has suggested that minor low-grade trauma, such as “rubbing, ear pulling, sleeping on hard pillows, or earphones,”² can lead to degeneration and subsequent separation of the auricular cartilage. Similarly, Ng et al. described a higher incidence of PCA in the setting of atopic dermatitis, hypothesizing that the pruritus of atopic dermatitis and subsequent rubbing causes sufficient trauma to induce PCA.³ Others have reported an embryologic defect in the cartilage,⁴ producing unstable residual tissue planes that spontaneously reopen, fill with fluid, and form the basis of a pseudocyst.⁵ 


PCA is uncommon, leading to frequent misdiagnosis of the condition. PCA is seen more often in males in the third to fourth decade of life, and has been noted more often in men of Chinese or European ancestry.⁶ 


A diagnosis of PCA is often made clinically or histologically. Histologic examination of the pseudocyst would reveal an intracartilaginous cavity without an epithelial lining.¹ The clinical differential diagnoses would include chondrodermatitis nodularis helicis, subperichondrial hematoma, traumatic perichondritis, relapsing perichondritis, and gouty tophi. 


Several treatment options for PCA have been suggested. However, there is a high rate of recurrence. The foremost goal of treatment should be preservation of the anatomic architecture. The most common treatment is surgical excision or drainage, followed by application of a pressure bandage. One case study described resolution of PCA with a simple 3-mm punch biopsy of the inferior border of the cyst followed by 2 weeks of daily application of a pressure bolster.⁶ Clinicians should be aware of the risk for local infection and pressure necrosis with this technique. 


The use of systemic or intralesional corticosteroids is controversial. Patigaroo et al. suggested that observing the patient for worsening of the deformity for 2 to 3 months may be appropriate, after finding in their study that observation was equally as effective as intralesional corticosteroid use.⁷ Oyama et al. described 2 cases of successful treatment with use of intralesional injections of minocycline.⁸ After needle aspiration of the intralesional fluid, 1 mg/mL of minocycline hydrochloride was injected at 2-week intervals. The lesions resolved after 2 and 3 treatments. 


The patient in this case was referred to a dermatologic surgeon at a nearby university for expert consultation. As of the last follow-up, the patient had chosen to observe the lesion for signs of progression and reported no further worsening of the deformity. 


Esther Stern, NP-C, is a family nurse practitioner at Advanced Dermatology & Skin Surgery, P.C., in Lakewood, N.J.


---

This The Clinical Advisor CME activity consists of 3 articles. To obtain credit, read Vesiculobullous rash with atopic dermatitis and Plaques with hyperpigmented borders. Then take the post-test here.

---