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Journal of Pediatric Surgery (2008) 43, E29–E31

Mediastinal and pulmonary infantile myofibromatosis:an unusual surgical presentationMelissa Short a, A. Dramis a, P. Ramani b, Dakshesh H. Parikh a,⁎

aDepartment of Pediatric Surgery, Birmingham ChildrenTs Hospital, Steelhouse Ln, Birmingham B4 6NH, United KingdombDepartment of Histopathology, Bristol Royal Infirmary, Bristol BS1 3NU, United Kingdom

Received 17 December 2007; revised 21 June 2008; accepted 22 June 2008

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Key words:Visceral infantilemyofibromatosis;

Children;Pneumonectomy;Emphysematous left lung;Stridor

Abstract A 4-week-old boy was extensively investigated for stridor and respiratory distress and wasfound to have a soft tissue mass superior to the left hilum and emphysema of the entire left lung. Anexploratory thoracotomy was undertaken for diagnosis and possibly to improve respiratory distress.Intraoperatively, a firm plaquelike mass was identified encasing the entire hilum including leftpulmonary artery and left main bronchus. It became apparent that a left pneumonectomy was needed tobe performed to resect the tumor completely and achieve hemostasis. Histopathologic examinationrevealed infantile myofibromatosis with multiple foci within the entire lung parenchyma as well as inthe hilar mass. The child is completely recurrence-free and symptom-free after 6 years of follow-up. Theliterature review was carried out to discuss management of this rare but benign and surgicallychallenging condition.© 2008 Elsevier Inc. All rights reserved.

Infantile myofibromatosis (IM) is a rare mesenchymaldisorder with an unknown etiology, where tumors aredetected in the periphery in skin, subcutaneous tissues,muscles, bones, or within viscera [1-3] including the centraland peripheral nervous system [4]. Although IM was firstreported in 1954 [5], definitive description with differentterminologies such as congenital generalized fibromatosis,multiple congenital mesenchymal tumors, diffuse congenitalfibromatosis, and multiple vascular leiomyomas of thenewborn [3,6] are sited in literature since 1980.

⁎ Corresponding author. Birmingham Children's Hospital NHS Trust,teelhouse Ln, Birmingham B4 6NH, United Kingdom. Tel.: +44 0121 333090; fax: +44 0121 333 8081.E-mail address: dakshesh.parikh@bch.nhs.uk (D.H. Parikh).

022-3468/$ – see front matter © 2008 Elsevier Inc. All rights reserved.oi:10.1016/j.jpedsurg.2008.06.046

Two types of IM with characteristic firm rubbery nodulesboth with similar histologic appearances have been describedas (a) solitary type, involving the skin, muscles, andsubcutaneous tissue, is usually a benign self-limitingdisorder; however, a case of destructive proliferation of thesubcutaneous myofibroblastic nodules has been reported [7],and (b) commonly reported multifocal variety, involving thesubcutaneous tissue alone, or the musculoskeletal system,viscera as well as subcutaneous tissue.

Surgical management of IM involving the hilum of thelung and a multifocal visceral component involving only theleft lung parenchyma is described in this report. An infantilemediastinal soft tissue mass causing symptoms of tracheo-bronchial obstruction that resulted in a curative surgicalresection and long-term survival in a multifocal visceral IMis to our knowledge the first reported case. The report

E30 M. Short et al.

reviews English literature to discuss the management optionsand diagnostic difficulties.

Fig. 2 Cardiac catheterization with pulmonary angiogram. Theangiogram was undertaken as magnetic resonance imaging wassuggestive of a vascular mediastinal lesion. This shows a narrow leftpulmonary artery as indicated by the line.

1. Case report

A 4-week-old boy, with noticeably noisy breathing, adegree of respiratory distress with tachypnea, subcostalrecession, and a hyperinflated chest, was referred from aperipheral pediatric hospital. He was born at 37 weeks with abirth weight of 2835 g and after an uncomplicatedpregnancy. The family history was unremarkable. Althoughat birth a short-lasting episode of cyanosis was observed, hewas subsequently discharged home after a period ofobservation. He was thriving at home, until readmissionwith respiratory distress and stridor. Clinical examinationidentified decreased air entry on the entire left lung, wheeze,and oxygen saturations between 88% and 91% in air. A chestx-ray showed hyperinflation of the entire left lung withmediastinal shift to the right.

Computerized tomography of the chest with intravenouscontrast showed emphysema of the entire left lung withmediastinal shift and atelectasis in the right upper lobe. Therewas some evidence of a mediastinal mass in the leftparatracheal region but no evidence of a pulmonary arterysling. Magnetic resonance imaging confirmed the presenceof a soft tissue echogenic mass in the hilum compressing theleft main bronchus and extending superiorly. An echocardio-gram was normal. A ventilation-perfusion (V/Q) scanshowed no ventilation and very little perfusion (9%) of theleft lung (Fig. 1). An angiocardiogram revealed a narrowedleft pulmonary artery in the region of the hilum (Fig. 2). Aflexible fiber-optic bronchoscopy showed a completelyflattened but negotiable left main bronchus in the region ofthe left pulmonary artery, beyond which the bronchiappeared normal. A skeletal survey was unremarkable.

An exploratory thoracotomy was performed with a viewto achieve diagnosis and, if possible, to excise the soft tissuemass that was causing compression. A firm plaquelike masswas identified in the hilum of the left lung engulfing the mainpulmonary artery and bronchus. During the dissection of thepulmonary artery, it became apparent that the artery was

Fig. 1 Ventilation-perfusion scan. The V/Q scan suggested lossof function in the emphysematous left lung.

intimately involved in the mass. An accidental injury andintraoperative hemorrhage necessitated ligation of the leftpulmonary artery inside the pericardium. Ligation of theveins and bronchus was possible, proximal to the soft tissuetumor to achieve adequate resection. The lack of function inthe left lung, as suggested by V/Q scan, and ligation ofpulmonary artery to control bleeding led to an intraoperativedecision to perform a pneumonectomy.

Histologic examination of the lesion showed a biphasicpattern comprising interlacing fascicles of spindle cells andmore cellular vascular areas resembling hemangiopericytoma.Secondary changes including focal coagulative necrosis andcalcification were evident. The tumor protruded into thebronchial lumen and penetrated the wall into the peribronchialhilar soft tissue. The tumor also encircled the portion of thepulmonary vein, but it did not compromise or involve thelumen. Immunologic stains showed immunoreactivity ofthe spindle cells to actin, vimentin, and CD34. Occasionalcells were positive to desmin. The cellular areas were positiveto CD34 but negative to actin, desmin, and vascular markers(F8 related-antigen, Ulex, and CD31). These findings led tothe diagnosis of infantile myofibromatosis.

The child's postoperative course was uncomplicated, andhe was discharged after 6 days. At follow-up, he is thrivingwith no respiratory symptoms and was treated prophylacti-cally with antireflux medications. There has been norecurrence reported at 5-year consecutive magnetic reso-nance imaging of his chest.

2. Discussion

Clinical presentations of visceral IM are site-specific,multifocal, related to compression of the surrounding

E31Mediastinal and pulmonary infantile myofibrosis

structures, and occasionally have been mistaken withhemangioma because of increased vascularity [3]. Invariably,the visceral IM is associated with superficial nodules, andtherefore, the diagnosis can be achieved by the biopsy of theperipheral nodules. The multifocal visceral IM should beinvestigated for the bony lesions primarily by a skeletalsurvey, and additional imaging depends on the clinicalindications [8]. In our case, clinically, radiologically, andhistologically, only one lung and hilum was affected withIM, and therefore, the diagnosis was not possible withoutmajor intervention. This case is unusual as no other foci ofIM were identified.

Electron microscopic studies and cytoplasmic labeling ofspindle-shaped cells using fluorescein-conjugated anti-smooth muscle antibody have confirmed myofibroblast asthe originating tumor cell [9]. The histologic IM shows anangiocentric-angiogenic proliferative disorder of myofibro-blasts [10]. The histologic diagnosis can be confusing andrequires immunohistochemical staining with actin, vimentin,CD34, desmin, and vascular markers.

The prognosis is significantly less favorable and withreported associated mortality in visceral IM with pulmonaryinvolvement. In one literature review, mortality (15.5%) wasrecorded only in visceral and/or pulmonary IM cases [11].Roggli et al [12] reviewed 16 patients with pulmonary IMwith reported survival in only 2 cases; the mortality in 5 oftheir cases was because of bronchopneumonia or progressiverespiratory distress. Our case was carefully followed up atlong-term for both recurrences locally as well as in other sitesfor its multifocal occurrence.

The management of an infantile IM essentially needscareful monitoring once the diagnosis is made. Most lesionsare known to regress spontaneously; therefore, surgicalintervention is reserved for those who are symptomatic orwhen vital structures are threatened. However, the regressionof the tumor after partial excision was recorded to be in therange between 7% and 10.6% [13]. Treatment options otherthan surgery in difficult unresectable or recurrent cases

include local glucocorticoid injections [14], chemotherapy,and radiotherapy; all of these have been tried in childrenwithout proven success [15].

References

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