Pediatric Imaging • Review Kaneda et al. Pediatric and Adolescent Breast Masses Pediatric Imaging Review Pediatric and Adolescent Breast Masses: A Review of Pathophysiology, Imaging, Diagnosis, and Treatment Heather J. Kaneda1 OBJECTIVE. Pediatric breast masses are relatively rare and most are benign. Most are Julie Mack either secondary to normal developmental changes or neoplastic processes with a relatively Claudia J. Kasales benign behavior. To fully understand pediatric breast disease, it is important to have a firm Susann Schetter comprehension of normal development and of the various tumors that can arise. Physical ex- amination and targeted history (including family history) are key to appropriate patient man- Kaneda HJ, Mack J, Kasales CJ, Schetter S agement. When indicated, ultrasound is the imaging modality of choice. The purpose of this article is to review the benign breast conditions that arise as part of the spectrum of normal breast development, as well as the usually benign but neoplastic process that may develop within an otherwise normal breast. Rare primary carcinomas and metastatic lesions to the pediatric breast will also be addressed. The associated imaging findings will be reviewed, as well as treatment strategies for clinical management of the pediatric patient with signs or symptoms of breast disease. CONCLUSION. The majority of breast abnormalities in the pediatric patient are be- nign, but malignancies do occur. Careful attention to patient presentation, history, and clini- cal findings will help guide appropriate imaging and therapeutic decisions. hough breast masses are uncom- mary breast cancer is extremely low in the pe- mon in the pediatric population, diatric population, reducing the utility of mam- the detection of an abnormality is mography as a diagnostic problem-solving tool T often alarming to caregivers and [1]. Ultrasound is generally the primary imag- patients. Fortunately, most breast conditions ing modality used in young patients, aiding in arising in the pediatric age group are benign. the initial diagnosis, assisting in imaging-guid- Integral to the evaluation of these patients is a ed biopsy when indicated, and offering a safe thorough clinical examination and history. method of follow-up. In the pediatric patient, Key factors that aid in diagnosis include the MRI of the breast is rarely used, though in Keywords: adolescent breast masses, pediatric breast masses, ultrasound length of time that the mass has been present, select cases, it may be useful for surgical associated pain or other symptoms, whether planning or assessing the extent of disease. DOI:10.2214/AJR.12.9560 the mass affects one breast or both, how rap- idly the mass is growing, and, finally, any Benign Breast Disease Received July 6, 2012; accepted after revision August 26, 2012. family history of breast disease [1]. The most common benign pediatric breast Because most breast tumors in young people lesions can be divided into two main groups: 1 All authors: Department of Radiology, Penn State are benign, a conservative approach is warrant- those that arise as part of the spectrum of University, PO Box 850, Hershey, PA 17033. Address correspondence to J. Mack ([email protected]) and ed. Diagnosis and treatment must be tailored normal breast development and those that H. J. Kaneda ([email protected]). to avoid damaging developing breast tissue, arise as a usually benign but neoplastic pro- which can result in hypoplasia or aplasia [1]. cess within an otherwise normal breast. CME/SAM In the pediatric population, mammography This article is available for CME/SAM credit. plays no significant role in the evaluation of Normal Breast Development WEB breast disease for several reasons. First, the ex- Breast tissue begins to develop at approxi- This is a Web exclusive article. posure of breast tissue to ionizing radiation can mately week 5 of gestation, arising from the induce cellular changes that may lead to the ectoderm on the ventral surface of the em- AJR 2013; 200:W204–W212 Downloaded from www.ajronline.org by University Of Chicago Library on 05/12/13 IP address 128.135.12.127. Copyright ARRS. For personal use only; all rights reserved development of malignancy. Second, young bryo along a curvilinear ridge known as the 0361–803X/13/2002–W204 breast tissue can be extremely dense mammo- “Hughes line” or the “milk line,” extending graphically, reducing the overall sensitivity of from the axilla to the groin [2]. The majority © American Roentgen Ray Society the examination. Finally, the incidence of pri- of the milk line disappears shortly after its W204 AJR:200, February 2013 Pediatric and Adolescent Breast Masses formation, except for a portion at the ante- cocious puberty. Ultrasound allows the ex- idiopathic [7]. Elevated serum estrogen levels rior fourth intercostal space [3]. At approxi- clusion of an underlying breast mass and can can be caused by increased production of es- mately 10 weeks, the primitive ectodermal- also be used to evaluate the pelvis for signs trogen from testicular tumors (Leydig cell tu- ly derived breast tissue begins to proliferate, of early sexual development [6]. mors) or adrenocortical neoplasms. Increased growing into the dermis and forming the pri- aromatization of the precursors of estrogen mary mammary bud. Over time, the prima- Asymmetric Breast Bud Development can result in the elevation of estrogens and ac- ry bud begins to branch, forming secondary Early normal breast development can be counts for the gynecomastia associated with buds, which ultimately form the mammary quite asymmetric, with up to a 2-year differ- Sertoli cell and sex-cord testicular tumors lobules. The buds continue to branch and in- ence between breasts in the overall timing and in testicular germ cell tumors, liver dis- crease in length and, by the 20th week, form [1]. The asymmetric breast tissue presents as ease (cirrhosis), hyperthyroidism, Klinefel- small openings that fuse to form the lactifer- a unilateral subareolar mass. The role of ul- ter syndrome, and hyperthyroidism. Congeni- ous ducts, which converge into a small open- trasound again is to provide verification that tal testicular aplasia or hypoplasia, testicular ing, forming the nipple. The breast tissue in normal breast tissue is present and to ex- trauma or torsion, viral orchitis, and congeni- the full-term newborn is a discrete palpable clude an underlying mass, reassuring both tal anomalies (such as Klinefelter syndrome) nodule, which may persist for 6–12 months. the patient and parents. can all be associated with decreased testos- Thereafter, the breast tissue involutes and is terone levels and may lead to pathologic gy- essentially identical in boys and girls until Gynecomastia necomastia. Medications such as spironolac- the onset of puberty [4]. Gynecomastia is the excessive develop- tone and ketoconazole can displace estrogen The second phase of breast development ment of breast tissue in male patients. In the from sex hormone–binding globulin, result- occurs at puberty with the onset of thelar- pediatric population, it can be physiologic or ing in elevated free-estrogen levels. Finally, che, promoted by rising levels of estrogen and pathologic. Physiologic gynecomastia is gen- some herbal and skin care products (includ- progesterone. Estrogen stimulation produc- erally seen in three age groups: neonates, pu- ing those containing lavender and tea tree oil) es growth of ducts and fat, while progester- bertal boys (who develop pubertal or patho- have weak estrogenic and antiandrogenic ac- one stimulation results in lobular and alveo- logic gynecomastia), and elderly men. tivity that may cause gynecomastia [11]. lar budding. The mean age for thelarche in the Neonatal breast hypertrophy is a common Typically, ultrasound does not play a pri- United States is 8.87 years for African-Amer- transient condition seen in up to 90% of all mary role in the evaluation of the breast in ican girls and 9.96 years for white girls [5]. newborns, both male and female [7]. It is pre- pubertal gynecomastia. If the physical ex- sumed to be caused by transient elevations in amination is suggestive of gynecomastia, a Developmental Breast Lesions estrogen due to transplacental passage of the thorough history and laboratory assessment Prepubertal or peripubertal developmen- hormone [8]. Parental reassurance is general- should follow. However, if the physical find- tal breast lesions can be asymmetric or uni- ly all that is warranted, and ultrasound plays ings are questioned, ultrasound allows verifi- lateral and include premature thelarche, little role in treating these patients. cation of normal-appearing breast tissue and asymmetric development of breast buds, su- Pubertal gynecomastia can be seen in the exclusion of an underlying mass. Ultra- pernumerary breast tissue, and gynecomas- 3.9–64.6% of boys, depending on the criteria sound is also helpful in revealing a lack of tia. Postpubertal variations of development used to define gynecomastia [9]. It is gener- breast tissue in cases of pseudogynecomas- include mammary duct ectasia, cystic breast ally seen in boys aged 10–13 years, with typ- tia [12], which is breast enlargement caused changes, and infection. ical onset 6 months after the appearance of by fat deposition. Although testicular neo- secondary sex characteristics. Pubertal gy- plasms peak in incidence after puberty, tes- Abnormalities of Embryogenesis necomastia is a benign process that should ticular cancer can be associated with gyne- If fragments of the milk line persist abnor- regress within 2 years of onset (usually by comastia, which may be the only clinical mally, accessory nipples (polythelia) or su- age 17 years). Half of patients report a fam- finding at diagnosis. Ultrasound can be used pernumerary breasts (polymastia) may devel- ily history of gynecomastia [9]. to evaluate for the presence of testicular neo- op. Accessory nipples or accessory breasts are The cause of pubertal gynecomastia is plasms if indicated in these patients (Fig. 1). generally found along the course of the mam- unknown. In the past, an imbalance of tes- mary ridge, most commonly in the axilla.