Ultrasound Evaluation of Costochondral Abnormalities in Children Presenting With Anterior Chest Wall Mass

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1 Pediatric Imaging Original Research Supakul and Karmazyn Ultrasound of ostochondral bnormalities Pediatric Imaging Original Research Nucharin Supakul 1 oaz Karmazyn Supakul N, Karmazyn Keywords: anterior chest wall, cartilage, costochondral junction, osteochondroma, ultrasound DOI: /JR Received ugust 15, 2012; accepted after revision October 2, oth authors: Pediatric Radiology Section, Riley Hospital for hildren, 705 Riley Hospital Dr, Rm 1053, Indianapolis, IN ddress correspondence to N. Supakul (tsupakul@iupui.edu). WE This is a web exclusive article. JR 2013; 201:W336 W X/13/2012 W336 merican Roentgen Ray Society Ultrasound Evaluation of ostochondral bnormalities in hildren Presenting With nterior hest Wall Mass OJETIVE. The purpose of this article is to summarize our experience with the use of ultrasound for evaluation of costochondral cartilage deformity in patients presenting with an anterior chest wall mass. MTERILS ND METHODS. From 2007 to 2012, we identified all patients at our tertiary care children s hospital younger than 18 years old who underwent ultrasound for a clinical indication of anterior chest wall mass of unknown cause. pediatric radiologist reviewed all ultrasound examinations and other pertinent radiology examinations as well as prior and follow-up clinical history and determined the final clinical cause of the mass. RESULTS. We identified 16 patients (nine girls and seven boys; age range, 11 months to 16.1 years; mean, 7.5 years). ll patients presented with a firm anterior chest wall mass. Three patients had pain. Thirteen patients had prior imaging studies, including chest radiography (n = 13), T of the chest (n = 1), MRI of the breast (n = 1), and ultrasound of the chest wall (n = 1). In all prior studies the cause of the anterior chest wall mass was missed. Ultrasound showed an angular deformity of a single-level (n = 13) or multilevel (n = 1) costal cartilage, hypertrophy and elongation with mild angulation of the costal cartilage (n = 1), and osteochondroma (n = 1). ONLUSION. Targeted chest ultrasound is a useful diagnostic tool in the evaluation of costochondral cartilage deformities and should be considered in children with a firm anterior chest wall mass and negative radiography. D iagnosis of an anterior chest wall mass in children can be challenging because of the wide spectrum of causes, including normal variation, rib deformity, and benign and malignant tumors [1 6]. The most common cause of an anterior chest wall mass in children is deformity of the ribs [1 4, 7, 8]. Rib tumors, although rare, may have the same presentation. Therefore, imaging may be required to exclude tumors [1 5]. Radiography or cross-sectional imaging with either T or MRI is usually performed for evaluation of an anterior chest wall mass [1 4, 7, 8]. lthough patients are often referred for cross-sectional imaging, Donnelly et al. [1, 4, 7, 8] showed in a series of patients with asymptomatic palpable anterior chest wall lesions who underwent either T or MRI that all lesions were benign. This is usually related to normal variation in the bone or cartilage of the chest wall and is of no clinical importance. If nonbenign disease appears to be at least very infrequent, the question arises of whether exposure to ionizing radiation via T or the use of an expensive modality (MRI) is needed in this patient population. Ultrasound can directly show the costal cartilage that is occult on chest radiography and therefore can be used to evaluate for costochondral abnormalities when chest radiography is negative. lthough the use of ultrasound for evaluation of a chest wall mass has been suggested in some articles [9, 10], to our knowledge, there are no published series on the experience of using ultrasound for evaluation of chest wall abnormalities. The purpose of this study is to share the experience at our tertiary care children s hospital in using ultrasound in the evaluation of anterior chest wall masses. For several years, we have performed ultrasound in patients with known or suspected chest wall masses who had negative chest radiography. Materials and Methods Patients retrospective review was performed on all patients who were under 18 years old who underwent ultrasound for a clinical indication of a palpable firm W336 JR:201, ugust 2013

2 Ultrasound of ostochondral bnormalities TLE 1: Presentation, Findings, and Treatment in 16 Patients Patient No. Sex ge a History Ultrasound Diagnosis Other Imaging Treatment 1 oy 1 year 9 months Mass Single-level angular deformity hest radiography Observe 2 Girl 2 years 9 months Mass Single-level angular deformity hest radiography Observe 3 oy 12 years 10 months Mass Single-level angular deformity hest radiography Observe 4 oy 15 years 3 months Mass Single-level angular deformity hest radiography Observe 5 Girl 14 years 7 months Mass Single-level angular deformity hest radiography, outside MRI of breast Observe 6 Girl 6 years 11 months Mass Single-level angular deformity hest radiography, outside T of chest Observe 7 oy 7 years 7 months Mass Single-level angular deformity hest radiography Observe 8 Girl 1 year 2 months Mass Single-level angular deformity Observe 9 oy 7 years 8 months Mass Single-level angular deformity Observe 10 Girl 9 years 1 month Mass, pain Single-level angular deformity hest radiography Observe 11 oy 1 year 9 months Mass Single-level angular deformity hest radiography Observe 12 Girl 10 years 7 months Mass, pain Single-level angular deformity hest radiography, outside ultrasound of chest Observe 13 Girl 9 years 7 months Mass, pain Osteochondroma hest radiography Surgical resection 14 Girl 1 year Mass Multilevel wavy cartilage contour of thoracic cage hest radiography Observe 15 Girl 11 months Mass Single-level angular deformity hest radiography Observe 16 oy 16 years 1 month Mass Multilevel hypertrophy and elongation of cartilage Observe a ge when ultrasound was performed. anterior chest wall mass between pril 2007 and July 2012 and had no history of malignancy. Our institutional review board approved this HIPcompliant study with waiver of informed consent. From the medical records, we documented demographic data, clinical presentation (including whether the mass was painful), underlying disease (if any), and treatment. The original ultrasound diagnosis was recorded. We also documented the results of available prior pertinent radiologic studies, including ultrasound at other institutions. Imaging Technique fellowship-trained pediatric radiologist with 15 years of experience and a certification of added qualification performed all ultrasound studies. The focused anterior chest wall ultrasound was performed with the patient in the supine position. high-resolution MHz linear transducer and HDI 5000 or IU 22 ultrasound system (both systems, Philips Healthcare) was used. Gray-scale transverse and longitudinal images were obtained in the region of the chest mass and compared with the ipsilateral chest wall at the level above and below this region as well as the contralateral chest wall at the level of the mass. Results The study group included 16 patients (nine girls and seven boys) with a mean age of 7.5 years (range, 11 months to 16.1 years). ll patients presented with an anterior chest wall mass. Three also had pain. Prior imaging studies included chest radiography (n = 13), T of the chest (n = 1), MRI of the breast (n = 1), and ultrasound of the chest obtained at another institution (n = 1). ll reports from prior studies were negative for the cause of the chest mass. linical and ultrasound findings are summarized in Table 1. Three patients (numbers 8, 9, and 16) did not undergo any other imaging studies before the chest ultrasound. In patient number 8, the ordering physician knew we had experience with chest ultrasound and suspected that the chest mass involved the cartilaginous rib. In the patients 9 and 16, there was an order for T of the chest. The order was changed after discussion with the referring physician. On ultrasound, 15 patients (94%) had a diagnosis of angular deformities of the costochondral junction. There were 13 patients with a single-level angular deformity (Figs. 1 and 2), one patient with multilevel angular deformities (Fig. 3), and one patient with multilevel mild angular deformities with hypertrophy and elongation of the costal cartilage (Fig. 4). One patient (6%) had a bony mass at the costochondral junction with a cartilage cap typical for osteochondroma (Fig. 5), which was later resected with diagnosis confirmed by pathology. Discussion hildren who present with an anterior chest wall mass may pose a diagnostic dilemma for the clinician because of the wide differential diagnosis. lthough the cause is most commonly benign and no treatment is required, imaging may be important in some cases to exclude a malignant tumor [1, 2, 4, 5, 7]. primary neoplasm of the chest wall is uncommon and accounts for only 5 10% of all bone tumors [3, 5]. Malignant tumors are more common than benign tumors [3, 5]. The most common malignant primary bone tumor is the Ewing sarcoma family of tumors [1, 3 6]. Metastases are uncommon [4]. The most common JR:201, ugust 2013 W337

3 Supakul and Karmazyn Fig. 1 ngular deformity of single costal cartilage in 6-year-old girl with history of right anterior chest wall lump. T of chest showed normal findings. Fig. 1 ngular deformity of single costal cartilage in 6-year-old girl with history of right anterior chest wall lump. T of chest showed normal findings. and, Focused ultrasound images of anterior chest wall show abnormal angular contour of cartilage at right chest wall () compared with normal contour of left rib ()., T image of chest initially read as having negative findings. Retrospective evaluation revealed angular deformity of right costochondral cartilage (arrow) corresponding with palpable area. Left chest wall at same level was in normal contour. Fig. 2 ngular deformity of single costal cartilage in 9-year-old girl with history of palpable mass in left anterior chest wall. and, Focused ultrasound images of anterior chest wall show abnormal contour of cartilage at left chest wall corresponding with palpable area () and normal costochondral contour of ipsilateral chest wall at superior level ()., Drawing shows angular deformity of left costochondral cartilage (box) and normal right costochondral cartilage. (Reprinted with permission from the Trustees of Indiana University, Indianapolis, IN) W338 JR:201, ugust 2013

4 Ultrasound of ostochondral bnormalities Fig. 3 ngular deformities of multiple ribs in 1-year-old girl with history of palpable anterior chest wall mass bilaterally. and, Focused ultrasound images of right () and left () ribs show multilevel abnormal contour and angular deformities with wavy appearance of cartilaginous part of bilateral lower ribs., Drawing shows wavy appearance (boxes) of bilateral costochondral cartilage. (Reprinted with permission from the Trustees of Indiana University, Indianapolis, IN) Fig. 4 Multilevel angular deformities with hypertrophy and elongation of costochondral cartilage in 16-year-old boy with history of palpable right anterior chest wall mass for 4 years. D, Focused ultrasound images obtained in transverse ( and ) and longitudinal ( and D) planes show hypertrophy, elongation, and mild angulation of right anterior costochondral junction of right lower ribs ( and ) in accordance with patient s area of palpable abnormality. Left costal cartilage was normal in contour and thickness ( and D). (Fig. 4 continues on next page) D JR:201, ugust 2013 W339

5 Supakul and Karmazyn Fig. 4 (continued) Multilevel angular deformities with hypertrophy and elongation of costochondral cartilage in 16-year-old boy with history of palpable right anterior chest wall mass for 4 years. E, Drawing shows hypertrophy and elongation with mild angulation (box) of right costal cartilage. (Reprinted with permission from the Trustees of Indiana University, Indianapolis, IN) benign primary bone tumors are enchondroma and osteochondroma [3]. The most common cause of a palpable anterior chest wall mass in children is chest wall deformity [1, 2, 4, 7, 8]. hest wall deformities are common in children and occasionally can present as an anterior chest wall mass [1, 2, 4, 7, 8]. Imaging findings of these deformities were described in series using T and MRI [1, 2, 4, 7, 8]. ross-sectional imaging can show tilted sternum, parachondral nodules, and a mild degree of pectus excavatum or carinatum [1, 4, 7, 8]. Some of these deformities, such as prominent asymmetric costal cartilage, involve only the cartilage and cannot be identified on chest radiographs [7]. In our study, 13 patients (81%) had negative chest radiography. lthough we did not use a radiopaque marker in our patients, the radiopaque marker could be helpful because it may indicate the palpable mass in the expected location of the cartilaginous rib and confirm that it does not involve a bony structure. Fifteen patients (94%) had angular deformities of the costochondral junction; 13 patients had only one rib involved and two patients had involvement of multiple ribs (one of them also had hypertrophy and elongation of the costal cartilage). One patient had a benign tumor (osteochondroma). The rib at the costochondral junction is a metaphyseal equivalent. Therefore osteochondromas are more common in this location [11, 12]. To our knowledge, our study is the first to describe the experience of using ultrasound to evaluate palpable anterior chest wall masses in children. ompared with T, focused thoracic wall ultrasound is a relatively inexpensive and widely available alternative and, unlike T, does not use ionizing radiation [9]. In addition, young children may need to be sedated for T and MRI examinations. Two of our patients were evaluated by either T or MRI, both of which were reported as negative. Only on retrospective review of these studies can the costochondral defor- E Fig. 5 Osteochondroma at costochondral junction in 9-year-old girl who presented with painful palpable right anterior chest wall mass., Focused ultrasound image shows lobulated bony protuberance (arrowheads) at right costochondral junction with overlying hypoechoic area with smooth round rim suggestive of cartilage cap (arrow). = bone, = cartilage., Drawing shows osteochondroma at right costochondral junction with cartilaginous cap (box). (Reprinted with permission from the Trustees of Indiana University, Indianapolis, IN) mity be identified. The small FOV of ultrasound and the high contrast resolution of the hypoechogenic cartilage help depict the costochondral deformity. We had one outside ultrasound study that was negative. This shows that radiologists should be aware of the possibility of chondral deformity as a cause for the mass and not concentrate only on the soft tissues. ecause of our experience with ultrasound for evaluation of costochondral deformity, before performing a chest T, we first suggest evaluation with chest ultrasound. This policy resulted in a change of ordering the examination from T to ultrasound on the basis of the ultrasound interim result in four (25%) of our patients in Our study has several limitations. The series is relatively small and includes only 16 patients. ecause of the nature of rib deformity, there was generally no surgical or pathologic confirmation of the ultrasound findings. One other limitation is that all ultrasound examinations were performed and interpreted W340 JR:201, ugust 2013

6 Ultrasound of ostochondral bnormalities by a single pediatric radiologist, and interobserver variability could not be evaluated. 2. Wong KS, Hung IJ, Wang R, Lien R. Thoracic wall lesions in children. Pediatr Pulmonol 2004; symptomatic, palpable, anterior chest wall lesions in children: is cross-sectional imaging nec- onclusion In children with a palpable anterior hard chest wall mass and negative chest radiography, high-resolution ultrasound may be helpful to identify costochondral cartilage deformity as the cause of the mass, thus excluding tumor and obviating unnecessary radiation or more expensive imaging modalities, such as T or MRI. References 1. Donnelly LF, Donald PF, Joseph NF, Sara MO, George S III. nterior chest wall: frequency of anatomic variations in children. Radiology 1999; 212: : Glass R, Norton KI, Mitre S, Kang E. Pediatric ribs: a spectrum of abnormalities. Radio- Graphics 2002; 22: Donnelly LF. Use of three-dimensional reconstructed helical T images in recognition and communication of chest wall anomalies in children. JR 2001; 177: Kim S, Lee S, rsenault D, Strijbosch R, Shamberger R, Puder M. Pediatric rib lesions: a 13-year experience. J Pediatr Surg 2008; 43: Tateishi U, Gladish GW, Kusumoto M, et al. hest wall tumors: radiologic findings and pathologic correlation. Part 2. Malignant tumors. Radio- Graphics 2003; 23: Donnelly LF, Taylor N, Emery KH, rody S. essary? Radiology 1997; 202: Donnelly LF, Frush DP. bnormalities of the chest wall in pediatric patients. JR 1999; 173: hira R, hira, Mircea P. Thoracic wall ultrasonography: normal and pathological findings pictorial essay. Med Ultrason 2011; 13: Orth R, Laor T. Isolated costal cartilage fracture: an unusual cause of an anterior chest mass in a toddler. Pediatr Radiol 2009; 39: Nam SJ, Kim S, Lim J, et al. Imaging of primary chest wall tumors with radiologic-pathologic correlation. RadioGraphics 2011; 31: Guttentag R, Salwen JK. Keep your eyes on the ribs: the spectrum of normal variants and diseases that involve the ribs. RadioGraphics 1999; 19: JR:201, ugust 2013 W341