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 Table of Contents  
Year : 2017  |  Volume : 1  |  Issue : 1  |  Page : 22-24

Focal chest wall protuberance due to forked ribs or cartilages: An analysis of 12 cases

1 Department of Pediatrics, Division of Pediatric Pulmonology, Chang Gung Children's Hospital and Chang Gung University, Taipei, Taiwan, ROC
2 Department of Pediatrics, National Taiwan University Children's Hospital, Taipei, Taiwan, ROC
3 Department of Pediatrics, Chang Gung Memorial Hospital, Keelung and Chang Gung University, Taoyuan, Taiwan, ROC

Date of Web Publication14-Mar-2017

Correspondence Address:
Kin-Sun Wong
Department of Pediatrics, Chang Gung Children's Hospital, 5, Fu Hsin Street, Taoyuan 33305, Taiwan
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/prcm.prcm_13_16

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Objective: The purpose of this article is to describe and summarize the clinical manifestations and radiographic features of focal bulging of chest walls in children using plain chest radiography and computed tomography (CT) scans. Methods: From 2008 to 2014, we identified 12 patients with forked ribs younger than 18 years of age. These patients received plain chest radiography and computed tomographic scans of the chest for focal anterior chest wall protrusion at the outpatient chest clinic of a children's facility. Results: A total of 12 patients (5 girls and 7 boys; age range, 2–12 years; median, 5 years) were enrolled in this study. Six patients had right-sided costal lesions, four had left-sided lesions, and two had anomalies on both sides. The most common rib involved was the 4th rib. Two patients with forked cartilages and one patient with forked rib were not detected in frontal radiograph but seen by CT scans only. Up to the time of this writing, the follow-up of patients revealed no progression of focal bulging. Conclusion: In otherwise healthy children with asymptomatic focal anterior chest wall bulging, forked ribs is a common cause of variation. The chest radiographs may be normal. Chest CT scans demonstrated forked ribs/cartilage as the cause of focal bulging of the chest wall unequivocally in such instances.

Keywords: Bifid sternum, chest wall, forked cartilage, forked ribs

How to cite this article:
Wong KS, Huang YC, Lai SH, Chiu CY. Focal chest wall protuberance due to forked ribs or cartilages: An analysis of 12 cases. Pediatr Respirol Crit Care Med 2017;1:22-4

How to cite this URL:
Wong KS, Huang YC, Lai SH, Chiu CY. Focal chest wall protuberance due to forked ribs or cartilages: An analysis of 12 cases. Pediatr Respirol Crit Care Med [serial online] 2017 [cited 2023 Feb 8];1:22-4. Available from: https://www.prccm.org/text.asp?2017/1/1/22/201977

  Introduction Top

Protruding chest wall lesions in children are both worrisome for the parents and the primary care physicians alike. The diagnostic possibilities of focal bulging of the thorax include congenital costal or cartilaginous anomalies of developmental variations, infections, and benign and malignant neoplasms of soft tissue/bony origins.[1],[2],[3],[4],[5] Congenital chest wall anomalies can be observed as a single anomaly or as a symptom of various monogenic syndromes, chromosome aberrations, or disruption sequences.[6] Despite anatomical variations being the most common cause of chest wall protrusions in the pediatric population, the clinical manifestations of forked (or bifid) ribs were infrequently described.[7] This study described the experience of forked ribs in a single pediatric chest clinic and reviewed the literature.

  Methods Top


This is a retrospective observational study performed on patients aged below 18 years who had undergone chest radiography with/or without computed tomography (CT) scans with diagnoses of bifid ribs or cartilages. The patients were recruited from the database of patients visiting the chest clinic extended from January 2008 to December 2014. Our hospital is a university-affiliated hospital with walk-in-clinic serving the community. Patients presenting with primary pectus excavatum or carinatum were excluded from the analysis. Our Institutional Review Board approved the study with waiver of informed consent because the study only entailed a retrospective review of medical records (CGMH 102-3246B). From the medical charts, we retrieved demographic data, clinical presentations, underlying diseases, and confirmation of anomalies by helical CT scans with three-dimensional reconstruction if available.

  Results Top

A total of 12 patients were identified for the study (5 girls and 7 boys) with a median age of 5 years (range, 2–12 years) [Table 1]. Six patients had right-sided costal lesions, four had left-sided lesions, and two had anomalies on both sides [Figure 1]a and [Figure 1]b. Multiple forked lesions were seen in two patients, one patient on the left side (Case 3) and one patient on the right side (Case 7). The most common ribs involved were 4th rib (6 times), 3rd rib (5 times), 5th rib (4 times), and once for 1st and 6th ribs, respectively. One patient had simultaneous fusion of the 1st and 2nd ribs together with the 3rd forked rib. Three patients with bifid rib were not detected in frontal radiograph but seen by CT scans only. Case 11 suffered from 47 XXY anomaly. Case 12 had right-sided forked cartilage together with a cleft sternum [Case 12 in [Figure 2]. No patient required additional therapy for the forked ribs.
Table 1: Summary of clinical and radiological findings

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Figure 1: (a and b) The arrows in the figure demonstrate forked ribs in the right 5th, left 4th and 6th ribs, respectively (Case 8).

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Figure 2: Black arrow in the right side demonstrates forked cartilage in the 3rd rib and white arrow in the left side reveals cleft sternum (Case 12).

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  Discussion Top

Children presenting with focal bulging in the anterior chest wall are challenging to the clinicians because of the wide varieties of diagnostic possibilities.[1],[2],[3],[4],[5] Focal bulging of the chest wall can be caused by infections, such as empyema necessitates, osteomyelitis, or local abscess formations. However, most of these patients would show signs of infections including constitutional fever, local erythema, swelling, and tenderness.[4],[5] With the advance of modern molecular diagnostics, sternal or costal osteomyelitis due to Bacille Calmette–Gue´rin had been reported in increasing frequencies in the past decade and should be considered in endemic areas of M. tuberculosis infection as in Taiwan.[8],[9]

Primary neoplasms of the chest wall are uncommon and account for only 5%–10% of all bone tumors, metastases are even rarer.[1],[2],[3] Most of the patients with malignant soft-tissue masses in the chest wall present with painful masses, cough, dyspnea, and pleural effusion. Imaging studies are important for the diagnosis of treatable diseases and confirmation of malignant tumor or infection.[3],[4],[5]

In the study for asymmetrical chest wall bumps in children by Donnelly et al., only one patient had bifid rib among 26 reported patients.[10] Etter reported congenital rib anomalies in 544 (1.4%) men in the screening radiographs of 40,000 healthy young male military recruits; among whom 257 (0.6%) had fork ribs, usually the 4th rib was involved.[11] Bifid ribs were reported to occur in 0.15%–0.31% of the general population with a female predilection and occurred more frequent on the right side than the left side.[2],[3],[11] We found the most prevalent location of bifid ribs in this study to be the 4th rib (6 occasions), which was consistent with previous experience.[5] In this study of 12 patients, bifid rib anomaly was not mentioned in the routine report of frontal chest radiographs initially. Even with meticulous attention, three of the 12 patients had normal plain chest radiographs, and the true anomaly was not demonstrated even with bone reconstruction but well visualized with cartilage reconstruction algorithm only.

Only one patient had forked cartilage and associated cleft sternum in our study. Cleft sternum can be observed as a single anomaly or as a feature of various monogenic syndromes and chromosome aberrations.[12]

In the absence of pain, increasing size, or constitutional symptoms, physical examination is usually not rewarding, plain chest radiographs may reveal forked ribs if vigilantly looked for, but forked cartilages would be missed. No patient in this study had progression of the thoracic wall mass after a median follow-up of 3 years. Thoracic wall ultrasound was reported but the experience was limited.[13] With the availability of low-dose CT scans, it may be possible to demonstrate costal abnormalities with minimal radiation dosage with unequivocal diagnosis.

We were not able to calculate the true prevalence of forked ribs in a group of patients with chest wall bulgings because the total number of patients who had undergone investigations was not enumerated due to a retrospective analysis.

  Conclusion Top

In children with an asymptomatic focal anterior chest wall bulging, forked rib is the common cause. It is commonly seen in preschoolchildren in the right side, sometimes with multiple site involvement either ipsilaterally or contralaterally. Chest CT scans demonstrated forked ribs/cartilages as the cause of focal bulging of the chest wall unequivocally if plain chest radiographs were normal.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Wong KS, Hung IJ, Wang CR, Lien R. Thoracic wall lesions in children. Pediatr Pulmonol 2004;37:257-63.  Back to cited text no. 1
Donnelly LF, Frush DP, Foss JN, O'Hara SM, Bisset GS 3rd. Anterior chest wall: Frequency of anatomic variations in children. Radiology 1999;212:837-40.  Back to cited text no. 2
Glass RB, Norton KI, Mitre SA, Kang E. Pediatric ribs: A spectrum of abnormalities. Radiographics 2002;22:87-104.  Back to cited text no. 3
Fefferman NR, Pinkney LP. Imaging evaluation of chest wall disorders in children. Radiol Clin North Am 2005;43:355-70.  Back to cited text no. 4
García-Peña P, Barber I. Pathology of the thoracic wall: Congenital and acquired. Pediatr Radiol 2010;40:859-68.  Back to cited text no. 5
Kotzot D, Schwabegger AH. Etiology of chest wall deformities – A genetic review for the treating physician. J Pediatr Surg 2009;44:2004-11.  Back to cited text no. 6
Kaneko H, Kitoh H, Mabuchi A, Mishima K, Matsushita M, Ishiguro N. Isolated bifid rib: Clinical and radiological findings in children. Pediatr Int 2012;54:820-3.  Back to cited text no. 7
Kröger L, Korppi M, Brander E, Kröger H, Wasz-Höckert O, Backman A, et al. Osteitis caused by bacille Calmette-Guérin vaccination: A retrospective analysis of 222 cases. J Infect Dis 1995;172:574-6.  Back to cited text no. 8
Wong KS, Huang YC, Hu HC, Huang YC, Wen CH, Lin TY. Diagnostic utility of QuantiFERON-TB Gold In-Tube test in pediatric tuberculosis disease in Taiwanese children. J Microbiol Immunol Infect 2015. pii: S1684-118200820-8.  Back to cited text no. 9
Donnelly LF, Taylor CN, Emery KH, Brody AS. Asymptomatic, palpable, anterior chest wall lesions in children: Is cross-sectional imaging necessary? Radiology 1997;202:829-31.  Back to cited text no. 10
Etter LE. Osseous abnormalities in the thoracic cage seen in forty thousand consecutive chest photoroentgenograms. Am J Roentgenol Radium Ther 1944;51:359-63.  Back to cited text no. 11
Takaya J, Kitamura N, Tsuji K, Watanabe K, Kinoshita Y, Hattori Y, et al. Pentalogy of Cantrell with a double-outlet right ventricle: 3.5-year follow-up in a prenatally diagnosed patient. Eur J Pediatr 2008;167:103-5.  Back to cited text no. 12
Supakul N, Karmazyn B. Ultrasound evaluation of costochondral abnormalities in children presenting with anterior chest wall mass. AJR Am J Roentgenol 2013;201:W336-41.  Back to cited text no. 13


  [Figure 1], [Figure 2], [Figure 3]

  [Table 1]


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