Dermatology

Accessory tragus

Accessory Tragus

Synonyms for accessory tragus: supernumerary auricle, branchiogenic cartilaginous nevus, accessory external ear, skin papillus, and polyotia.

The term accessory tragus is most precise, because it represents a minor abberation of the embyrologic development of the first branchial arch. The tragus is the only part of the external ear derived from the first branchial arch.

744.1 accessory tragus

Are You Confident of the Diagnosis?

What you should be alert for in the history

Patients present with a soft or firm, skin-colored nodule arising anywhere along an imaginary line extending from on or near the tragus to the angle of the mouth (Figure 1). Accessory tragi may also arise on the neck along the anterior border of the sternocleidomastoid muscle, in which case they are referred to as congenital cartilaginous rests of the neck (aka., wattle). The lesion is non-tender. It is present since birth. The lesion may be bilateral, and multiple lesions may occur on the same side. Family history has been reported, but is uncommon.

Figure 1.

Accessory tragus (Courtesy of Bryan Anderson, MD)

Characteristic findings on physical examination

A soft or firm, small, skin-colored nodule is found arising anywhere along an imaginary line extending from on or near the tragus to the angle of the mouth. Accessory tragi may also arise on the neck along the anterior border of the sternocleidomastoid muscle. The location along the neck reflects the embryologic migration Less common locations include the glabella, suprasternal notch, and middle ear.

Expected results of diagnostic studies

Clinical diagnosis may be sufficient, since treatment intervention is optional. Biopsy will confirm the diagnosis with certainty. Pathology shows a thin stratum corneum and epidermis with numerous irregularly-spaced vellus hair follicles. Eccrine glands are usually present (Figure 2). The stroma consists of mature adipose tissue and a central plate of elastic cartilage in most specimens. Small amounts of skeletal muscle may be present.

Figure 2.

Accessory tragus. (Courtesy of Bryan Anderson, MD)

Diagnosis confirmation

The clinical differential diagnosis could include:

-acrochordon (aka, skin tag). Presents as a soft, skin-colored or hyperpigmented papule, usually located on the neck, axillae, groin, or periorbital skin. Histology shows polypoid growth of variably loose to dense collagenous stroma with thin-walled dilated blood vessels in the center.

-adnexal tumor. Typically flesh-colored papules arising from skin adnexa. Biopsy is necessary to determine the adnexal cells of origin, such as sebacous glands, eccrine glands, apocrine glands, or hair follicles.

-auricular fistula (aka, ear pit, preauricular cyst, congenital auricular fistula). A congenital defect that presents as a true cystic nodule or an invagination in the preauricular area. Histology shows a pit or cyst lined by stratified squamous epithelium with a granular layer. Cartilage is not present.

-branchial fistula. Presents as a sinus ostium, frequently with a mucous discharge, located on the lateral lower third of the neck along the anterior border of the sternocleidomastoid muscle. It is usually detected at birth or during the first few years of life. Biopsy shows a sinus lined by stratified squamous or pseudostratified ciliated columnar epithelium.

-branchial cleft cyst. Presents as a cyst in the preauricular area, mandibular region, or along the anterior border of the sternocleidomastoid muscle. Most commonly presents in the second or third decade. Histology shows a cyst lined by stratified squamous epithelium or by pseudostratified ciliated columnar epithelium.

-epidermal cyst. Presents as a mobile, dermal nodule or cyst, usually with a central punctum, which can be located anywhere on the body. Histology shows a cystic cavity filled with lataminated keratin lined by a stratified squamous epithelium that has a granular layer.

-hair follicle nevus (aka, vellus hamartoma). Presents as a small papule from which fine hairs protrude evenly from the surface that is often located on the face, commonly in the vicinity of the ear. Histology shows a domed surface from which closely set, but normally formed vellus follicle protrude. The absence of cartilage in the subcutaneous fat will distinguish the hair follicle nevus from an accessory tragus.

-lipoma. Presents as a round to oval, soft, mobile subcutaneous nodule with a normal overlying epidermis that may be located in the subcutaneous fat anywhere on the body. Does not have a predilection for the periauricular area.

-thyroglossal cyst. Presents as a midline cystic nodule on the anterior neck in children or young adults. A tract connecting the cyst to the hyoid bone is frequently present, resulting in a characteristic movement of the cyst with swallowing. Histology shows a cyst lined with cuboidal, columnar, or stratified squamous epithelium and may contain ciliated columnar cells. The characteristic histologic feature is the presence of thyroid follicles, characterized by low cuboidal cells surrounding homogenous pink material.

Who is at Risk for Developing this Disease?

The prevalence of accessory tragus as an isolated physical finding is estimated to be approximately 1.7:1000.

A family history of accessory tragus has been reported but is uncommon.

What is the Cause of the Disease?

Etiology

Accessory tragus is a congenital malformation of the external ear occurring as a result of anomalous development of the first branchial arch.

Pathophysiology

During the fourth week of embryonic life, the auricle begins to develop around the first branchial groove from tissue contributed by the first (mandibular) and second (hyoid) branchial arches. During the fifth week, three hillocks or surface irregularities appear on each arch. As the embryo grows, these six hillocks move dorsally and develop into the auricle’s structures. The first hillock forms the tragus. Accessory tragi may occur along the migratory line, as the auricle descends from the neck area to the tragus.

Systemic Implications and Complications

Most accessory tragi are isolated findings, unrelated to the any systemic disorders. However, accessory tragus may be associated with a variety of syndromes with associated developmental anomalies of the first and second branchial arches. These syndromes include:

1. Goldenhar syndrome (aka, oculoauriculovertebral syndrome). An autosomal recessively inherited condition for which accessory tragus is a constant feature. Additional findings included epibulbar dermoid cysts, vertebral defects, and auricular disorders. Facial abnormalities may be present, including maxillary and mandibular hypoplasia, antimongoloid slant to the eyelids, and fistulae in front of the tragi. Several other physical findings have been observed and mental retardation is occasionally noted.

2. Treacher-Collins syndrome (aka, mandibulofacial dysostosis). An autosomal dominantly inherited condition for which accessory tragus is NOT a constant feature. Other physical findings may include a hypoplastic maxilla and mandible, a high or cleft palate, and macrostomia.

Less common syndromes that may be associated with accessory tragi include 4p syndrome (Wolf-Hirschhorn syndrome), Townes-Brocks syndrome, and VACTERL syndrome. The latter two syndromes both present with anal, ear, renal, and radial congenital malformations.

If any of these syndromes is suspected based on physical findings in a patient presenting with accessory tragus, referral to a pediatric genetic specialist is warranted.

Treatment Options

As these lesions pose no threat to one’s health, observation is a reasonable management decision. If treatment is desired for aesthetic or diagnostic reasons, complete surgical excision is the treatment of choice. Excision should include all portions of the cartilage associated with the accessory tragus. Shave excision may result in incomplete removal of the cartilage, which may delay healing and increases the risk of postoperative chondrodermatitis.

Optimal Therapeutic Approach for this Disease

Management of the lesion depends on the desires of the patient and/or the parents. Either observation or complete surgical excision is a reasonable choice.

Patient Management

No additional treatment is necessary after after surgical excision. In Caucasian patients, a hearing evaluation and a renal ultrasound should be considered, even in the absence of classical syndromal features. In African-American patients, these tests are not usually necessary, especially if there is a family history of accessory tragi.

Unusual Clinical Scenarios to Consider in Patient Management

Most accessory tragi are isolated physical findings. Accessory tragi may occur bilaterally in approximately 6% of cases. More than one accessory tragus may occur on the same side.

What is the Evidence?

Chintalapati, K, Gunasekaran, S, Frewer, J. "Accessory tragus in the middle ear: A rare congenital anomaly". Int J Pediatr Otorhinolaryngol. vol. 74. 2010. pp. 1338-9.

(A case report of a rare presentation of accessory tragus in the middle ear.)

Jansen, T, Romiti, R, Altmeyer, P. "Accessory tragus: A report of two cases and review of the literature". Pediatr Dermatol. vol. 17. 2000. pp. 391-4.

(A case series of two pediatric patients, each with accessory tragi unrelated to systemic syndromes. Concise review of the literature on accessory tragus.)

Hodges, FR, Sahouria, JJ, Wood, AJ. "Accessory tragus: A report of 2 cases". J Dent Child. vol. 73. 2006. pp. 42-4.

(A case series of two pediatric patients, each with accessory tragi unrelated to systemic syndromes. Concise review of the literature on accessory tragus.)
You must be a registered member of Renal and Urology News to post a comment.

Sign Up for Free e-newsletters