Although rare, inflammatory myofibroblastic tumor is the most common primary lung mass in children. We report the case of an 11-year-old boy investigated for persistent cough and dyspnea with complete left lung atelectasis mimicking pneumonia. CT and MRI showed an endobronchial mass of the left main bronchus. The boy underwent endoscopic resection of the tumor and histology was in favor of an inflammatory myofibroblastic tumor of the lung. This diagnosis should be suspected in children with recurrent pneumonia. The prognosis is good after complete resectio

Anooshiravani, Mehrak

Barrazzone, Constance

Dhouib, Amira

Hanquinet, Sylviane

Reverdin, Alexandra

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CASE REPORTInflammatory myofibroblastic tumor of the lung: a rare causeof atelectasis in childrenAmira Dhouib & Constance Barrazzone &Alexandra Reverdin & Mehrak Anooshiravani &Sylviane HanquinetReceived: 8 March 2012 /Revised: 12 June 2012 /Accepted: 19 July 2012 /Published online: 13 November 2012# Springer-Verlag 2012Abstract Although rare, inflammatory myofibroblastic tu-mor is the most common primary lung mass in children. Wereport the case of an 11-year-old boy investigated for persis-tent cough and dyspnea with complete left lung atelectasismimicking pneumonia. CT and MRI showed an endobron-chial mass of the left main bronchus. The boy underwentendoscopic resection of the tumor and histology was in favorof an inflammatory myofibroblastic tumor of the lung. Thisdiagnosis should be suspected in children with recurrentpneumonia. The prognosis is good after complete resection.Keywords Inflammatory myofibroblastic tumor .Atelectasis . ChildrenIntroductionInflammatory myofibroblastic tumor (IMT) of the lung is arare benign tumor first described by Brunn in 1939, as cited byJeba et al. [1]. It belongs to the group of soft-tissue tumors andis also called inflammatory pseudotumor, fibrous histiocy-toma, plasma cell granuloma, plasmocytoma, solitary mastcell tumor, pseudoneoplastic pneumonia or fibroxanthoma.IMT can involve any anatomical location, but the lung is themost commonly affected site in children as well as in adults. Theother anatomical locations are head and neck, mesentery, liverand bladder. In children, IMT is the most common primary lungmass that can behave like malignant tumors. Clinical presenta-tion and radiologic findings are variable and not specific. Diag-nostic confirmation is based on histological examination.Case reportAn 11-year-old otherwise healthy boy had a 2-month historyof dyspnea and coughs and was treated for asthma with noclinical improvement. One month after the onset of respira-tory symptoms, he developed fever and the cough becamepersistent. Chest radiograph showed left lower lobe atelec-tasis. The diagnosis of pneumonia was established and anti-biotherapy prescribed. One month later, he was referred toour emergency department because of unsatisfactory clinicalcourse with complete left lung radiologic atelectasis (Fig. 1).White blood cell count, blood chemistry and CRP levelwere unremarkable. Tuberculin skin test was negative.Chest US showed pulmonary consolidation without signif-icant pleural effusion. Chest CTwas performed on a 16-slicemachine (GE LightSpeed, Waukesha, WI, USA) after intra-venous 2 ml/kg injection of a 300 mgI/ml contrast medium(CTDI of 6.44 mGy). Besides total atelectasis of the leftlung with mediastinal shift to the left and compensatoryoverinflation of the right lung, CT showed a well-delineatedhomogeneous mass of 1.8×1.2×1.7 cm in the left mainbronchus (Fig. 2). This lesion completely obstructed theA. Dhouib :M. Anooshiravani : S. HanquinetDepartment of Pediatric Radiology, University Children’s HospitalGeneva,Geneva, SwitzerlandC. BarrazzoneDepartment of Pediatric Pneumology, University Children’sHospital Geneva,Geneva, SwitzerlandA. ReverdinDepartment of Pneumology, Clinique La Tour,Geneva, SwitzerlandA. Dhouib (*)Unité de Radiopédiatrie, Hôpital Universitaire des Enfants,6 rue Willy Donzé,1211, Genève 14, Suissee-mail: amira.dhouib@hcuge.chPediatr Radiol (2013) 43:381–384DOI 10.1007/s00247-012-2508-xmain bronchus and was not enhanced by contrast material.Chest MRI was performed on a 1.5-T (Magnetom Avanto,Siemens, Erlangen, Germany) and imaging protocolincluded Balanced Steady-State Free Precession (bSSFP),coronal T1-weighted turbo spin-echo sequences (TR/TE641/22 ms), axial and coronal T2-weighted turbo spin echo(TR/TE 1,000/80 ms) and fat-suppressed T1-weighted spin-echo sequences after intravenous administration of gadobutro-lum (Gadovist, Bayer, Zurich, Switzerland) at a dose of0.1 mmol/kg body weight. MRI confirmed the presence of ahomogeneous mass in the left main bronchus with high signalintensity on T2- and T1-weighted images with no significantcontrast enhancement (Fig. 3). Whole-body MRI was alsoperformed and the protocol included 3-D inversion recovery(inversion time0160 ms) T2-weighted turbo spin-echo(SPACE, TR/TE 2,000/151 ms, isotropic voxel dimensions,1.4 mm), coronal T1-weighted spin-echo sequences (TR/TE550/11) and diffusion. No other lesion was found. On [F-18]-fluoro-2-deoxyglucose (FDG) PET/CT (Biograph 16; Siemens,Erlangen, Germany), this mass showed increased metabolism(SUVmax 21.8) (Fig. 4). No other hypermetabolic lesions werefound on PET/CT. Lung volumes were markedly decreasedwith a restrictive syndrome (total lung capacity 55% of pre-dicted) on spirometric studies. Bronchoscopy visualized theendobronchial tumor, which was obstructing incompletely thedistal end of the left main bronchus (Fig. 5). The polypoid shapeFig. 1 The chest radiograph shows complete left lung atelectasis withcompensatory overinflation of the right lungFig. 2 Contrast-enhanced and reformatted coronal (a) and axial (b)CT images show an obstructive homogeneous, well-circumscribed andnon-enhanced mass in the left main bronchus (arrows)Fig. 3 Axial T2-weighted MR image shows a well-delineated mass(arrow) with high signal intensity in the left main bronchus andatelectasis of the left lungFig. 4 Fused coronal PET/CT image demonstrates intense 18F-FDGuptake in the pulmonary mass (arrow)382 Pediatr Radiol (2013) 43:381–384of the tumor allowed total endoscopic resection with a diather-mic snare combined with argon plasma coagulation and nocomplications. Histological analysis revealed a mesenchymaltumor more commonly called inflammatory myofibroblastictumor. Cytogenetic analysis confirmed this diagnosis with pos-itive characteristic rearrangement at 2p23.9 of the gene codingfor the anaplastic lymphoma kinase receptor tyrosine kinase(found in 50% of IMT cases). Chest radiographs after resectionshowed complete resolution of the atelectasis. Spirometryshowed normal total lung capacity, and repeated bronchoscopiesat 1-month and 3-month follow-ups were normal.DiscussionMost of the causes of atelectasis in childhood are related toairway obstruction. Intrabronchial obstruction may be exog-enous due to foreign body, or to mucous plugs. Endobron-chial tumors are a rare cause of atelectasis.IMT is a rare lesion; it belongs to the group of soft-tissuetumors and has also been called inflammatory pseudotumor,fibrous histiocytoma, plasma cell granuloma, plasmocytoma,solitary mast cell tumor, pseudoneoplastic pneumonia, andfibroxanthoma. This is probably due to its predominant cellularcomponent. It can involve any anatomical location; however,the lung is the most commonly affected site [2]. Other frequentlocations include the bladder, mesentery, omentum, retroperito-neum, pelvis, gastrointestinal tract, liver, spleen, kidney andpancreas. Some tumors can be multifocal and involve severalorgans. The true incidence of IMT of the lung is difficult toestablish because of various nomenclatures used. However, it isrelatively rare among all primary lung neoplasms, accountingfor only 0.04%–0.7% of them [3]. According to many series,IMT is the most common primary childhood lung tumor, withan incidence ranging from 12% to 57% [2]. There is a near equalmale/female occurrence [2, 4].Pathophysiologically, an unregulated proliferation of in-flammatory cells seems to be present [3]. The cause of thisinflammatory response remains unknown. It has been hypoth-esized that an initial infection leads to IMT, and about 30% ofpatients have had a history of respiratory infection. In a casereport Fiocchi et al. [5] described a direct progression frominfectious disease to an IMT. Inflammatory lesions are thoughtto occur locally as a result of excessive response to tissuedamage [6]. Others believe it to be a real neoplasm induced bygenic reorganizations on the chromosome 23 [7].Most frequent symptoms are cough, hemoptysis, chestpain, dyspnea and fever. It may also be asymptomatic [7].Radiologic findings are variable and unspecific. The mostcommon radiologic presentation is a solitary peripheral well-circumscribed lung mass, with variable size between 1.5 cmand 14 cm according to a series of 28 cases reported by Kim etal. [8]. The endobronchial polypoid forms arising in the tra-chea or the bronchus are the rarest but have also been reported,as in our case. They can show atelectasis and obstructivepneumonia and can spread into the mediastinum.Contrast-enhanced CT or MRI is necessary to view theendobronchial mass that is not visible on the chest radiograph.CTand MRI allow a better characterization and delineation ofthe tumor. Contrast-enhanced CT shows a homogeneous orheterogeneous attenuated mass. Intralesional calcifications arepossible but rare, and are shown more frequently in pediatriccases [4, 7]. IMTs are also known to rarely form a cavity. Insuch cases, MRI shows intermediate signal intensity on T1-weighted images and high signal intensity on T2-weightedimages. Absent or delayed enhancement with contrast injec-tion on CT or MRI is described in the literature. Takayama etal. [4] reported two cases of IMT that were intra-pulmonarywell circumscribed masses. Dynamic contrast enhancementCT in both cases showed delayed enhancement. They specu-late that the delayed enhancement could be attributed toabundant fibrous tissues such as myofibroblasts [4]. Highfixation of 18F-FDG of IMT on PET has been described [7]and may be used for assessment of multifocal forms.Concerning transbronchial biopsy and transthoracic needlebiopsy, Cerfolio et al. [2] believe that they often lead to confusionbetween IMTand fibrohistiocytic neoplasms, nodular sclerosingHodgkin lymphoma, primary lung cancer and mediastinal fibro-sis. Indeed, histological findings of a fragment cannot exclude aneoplasm with surrounding inflammation. Complete resectionfor both diagnosis and treatment is mandatory.While inflammatory myofibroblastic tumor is a rare endo-bronchial tumor, it should be known as a possible cause ofatelectasis in children and distinguished from a malignancy.The treatment is surgical, and a favorable prognosis relies oncomplete resection.Fig. 5 Endoscopic view of the left main bronchus shows an obstruc-tive endobronchial massPediatr Radiol (2013) 43:381–384 383References1. Jeba J, John S, Backiyanathan S et al (2008) Inflammatory pseudo-tumour of the lung with sarcomatous brain metastasis. Eur J CancerCare (Engl) 17:412–4142. Cerfolio RJ, Allen MS, Nascimento AG et al (1999) Inflammatorypseudotumors of the lung. Ann Thorac Surg 67:933–9363. Rasalkar DD, Chu WC, To KF et al (2010) Radiological appearanceof inflammatory myofibroblastic tumour. Pediatr Blood Cancer54:1029–10314. Takayama Y, Yabuuchi H, Matsuo Y et al (2008) Computedtomographic and magnetic resonance features of inflammatorymyofibroblastic tumor of the lung in children. Radiat Med26:613–6175. Fiocchi A, Mirri GP, Santini I et al (1999) Progression from bron-chopneumonia to inflammatory pseudotumor in a seven-year-oldgirl. Pediatr Pulmonol 27:138–1406. Ochs K, Hoksch B, Frey U et al (2010) Inflammatory myofibro-blastic tumour of the lung in a five-year-old girl. Interact CardiovascThorac Surg 10:805–8067. Hantous-Zannad S, Esseghaier S, Ridene I et al (2009) Inflamma-tory myofibroblastic tumors of the lung: imaging features. J Radiol90:1851–18558. Kim JH, Cho JH, Park MS et al (2002) Pulmonary inflammatorypseudotumor—a report of 28 cases. Korean J Intern Med 17:252–258384 Pediatr Radiol (2013) 43:381–384

Inflammatory myofibroblastic tumor of the lung: a rare cause of atelectasis in children

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Inflammatory myofibroblastic tumor of the lung: a rare cause of atelectasis in children

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