A specimen submitted to a dermatopathologist or pathologist with the clinical diagnosis of tag or nodule may, on occasion, have histologic features that may be normal or characteristic but not for a particular location. Such a lesion could be considered ectopic (ektopos is Greek for “out of place”) and may be benign and of no systemic consequence, or it may be associated with an extracutaneous and potentially serious condition. Various types of ectopic tissue and their characteristic locations are listed in Table 18-1.
TABLE 18-1Typical anatomic sites of ectopic tissue ||Download (.pdf) TABLE 18-1 Typical anatomic sites of ectopic tissue
|SITE ||LESION |
|Preauricular cheek ||Accessory tragus |
|Lateral chest ||Accessory breast tissue/supernumerary nipple |
|1st or 5th digit ||Supernumerary/rudimentary digit |
|Umbilicus ||Endometriosis |
|Omphalomesenteric/urachal duct remnants |
|Metastatic tumors (Sister Joseph nodule) |
Synonyms: Preauricular tag, polyotia, accessory auricle anomaly, rudimentary ear, supernumery pinna, ear tag, wattle.
The tragus is the portion of the external ear derived from the first branchial arch. This, together with the second branchial arch, moves dorsally, forming the auricle. An accessory tragus may develop at any point along the migratory line that extends from the tragus to the angle of the mouth or along the anterior margin of the sternocleidomastoid muscle.1 Some synonyms for this anomaly, such as accessory auricle, may be less accurate, because the rest of the external ear is derived from the second branchial arch. Accessory auricular anomaly, as a reference to a cartilaginous core with overlying skin, similar to a tragus, may be more appropriate. In contrast, an accessory auricle is larger and morphologically resembles an additional pinna. Cases of polyotia are much rarer congenital anomalies.2
Accessory tragi are located commonly in the preauricular and buccal region, slightly above or below the level of the tragus. They may present more anteriorly on the cheek or along the line of the mandible, on the neck between the sternocleidomastoid muscle and the suprasternoclavicular region, or (rarely) on the glabella or suprasternal region.1,3 Lesions arising on the neck are referred to by some as wattles.4 Others consider wattles to be cutaneous cartilaginous rests.1 Accessory tragi typically present as pedunculated soft to cartilaginous papules; they may be solitary or multiple, unilateral or bilateral, and are often diagnosed clinically as skin tags or fibromas. Vellus hairs may cover the surface. Some authors refer to these as a subtype of accessory auricle, which are further classified according to the location (intraauricular, preauricular, and buccal) and protrusion pattern (pedunculated, sessile, areolar, remnant, or depressed).5 The pedunculated and sessile lesions may be spherical, ovoid, lobed, or nodular in morphology. A cartilaginous root is usually but not always present. The lesions are asymptomatic unless they become infected or ...