Sonographic Findings of Accessory Breast Tissue in Axilla and Related Diseases

Abstract

Accessory breast tissue results from failed regression of primitive mammary tissue and is most often located in the axilla. Accessory breast tissue itself is normal and should not be misdiagnosed as an abnormality. Both benign and malignant diseases that occur in the normal breast can also develop in accessory breast tissue in the axilla. In this pictorial essay, we show sonographic findings of normal accessory breast tissue in the axilla and various lesions that occur in accessory axillary breast tissue, along with other imaging findings and pathologic features.

Ectopic axillary breast tissue appeared in pregnancy and revealed by ultrasound

“…Ultrasound is the best imaging tool used to evaluate both palpable and non-palpable masses differentiating between the most common causes of axillary swelling (i.e. lipomas, lymphadenopathies, sebaceous and follicular cysts, hidradenitis suppurativa) [1]. Axillary hidradenitis suppurativa, the first clinical diagnosis that our patient received, is easy to rule out with sonography, since the typical findings have been described in 2013 by Wortsman and colleagues 4 [2]: widening of the hair follicles, dermal-epidermal thickness, dermal pseudocysts, fluid collections and fistulous tracts.…”

“…In comparison, ABT only consists in an island of breast tissue without any relationship to the overlying skin, often located very close to the normal breast position. Indeed the axilla is the most commonly involved site (bilateral or confined to the right side) [6], followed by the inframammary area [1,3,4]. When only supernumerary nipple or/and areolae are present, without any glandular tissue, the term polythelia is used [3,6].…”

“…The ectopic breast tissue is observed in 2% to 6% of the population [4], occurring more frequently among Japanese people and less frequently among whites [1,6].…”

Tejido mamario ectópico en vulva: reporte de caso y revisión sistemática de la literatura

“…La apariencia ultrasonográfica del tejido mamario tiene aspecto fibroductal y mezcla de elementos glandulares o grasos. Sirve además para diferenciar el tejido mamario accesorio de lipomas, linfadenopatías, quistes sebáceos, entre otros 8 .…”

Experience of Ultrasound-Guided Vacuum-Assisted Excision of a Phyllodes Tumor Arising From Ectopic Axillary Breast Tissue: A Case Report

“…An accessory breast tissue, with a prevalence of 0.6 to 6%, is caused by the failed regression of the primitive mammary tissue. Phyllodes tumors in the ectopic axillary breast tissue are very rare fibroepithelial tumors, and only few cases have been reported in the literature (1)(2)(3)(4). Surgical removal is the treatment of choice for phyllodes tumors to prevent recurrence.…”