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Infantile Myofibromatosis: A Nontraumatic Cause of Neonatal Brachial Plexus Palsy
Infantile Myofibromatosis: A Nontraumatic Cause of Neonatal Brachial Plexus Palsy Travis S. Tierney, MD, DPhil*, Brent J. Tierney, MD†, Andrew E. Rosenberg, MD‡, Kalpathy S. Krishnamoorthy, MD§, and William E. Butler, MD*
matic cause of neonatal brachial plexus palsy. Pediatr Neurol 2008;39:276-278.
Introduction Approximately 1 in every 2,000 neonates is born with an upper brachial plexus palsy [1-3]. Although iatrogenic birth trauma underlies the majority of these cases, nontraumatic etiologies should be considered when atrophy and fibrillation potentials are present at birth. This case report provides the illustrative example of a male infant born with ipsilateral injuries to the upper brachial plexus, sympathetic chain, and phrenic nerve who was found on further evaluation to manifest an underlying cervical tumor. Case Report
Tierney TS, Tierney BJ, Rosenberg AE, Krishnamoorthy KS, Butler WE. Infantile myofibromatosis: A nontrau-
Prenatal ultrasound at 34 weeks of gestation revealed an elevated left hemidiaphragm in a male fetus. An uncomplicated, elective cesarean section was performed at 37 weeks of gestation in anticipation of respiratory distress. However, the Apgar scores at 1 and 5 minutes were 7 and 8, and he did not require immediate ventilatory support. Left ptosis, anisocoria, and a flaccid left upper extremity prompted transfer to a tertiary referral hospital. Palpation of the limb revealed a concave glenohumeral joint space secondary to wasting of the deltoid and biceps, but without evidence of subluxation or fracture. The infant’s grip was preserved, and his hand was warm. No other obvious deformity or cutaneous stigmata indicative of a phakomatosis, shingles, or hemangioma were evident. He exhibited a good anal wink and no unusual leg reflexes to suggest a long-tract abnormality. Apart from Horner’s syndrome and the upper brachial plexus paralysis, the rest of the examination was unremarkable. In addition to the obvious hemidiaphragm elevation, a chest x-ray performed at admission revealed an internally rotated left forearm with flexion of the wrist and fingers (Fig 1), but no congenital diaphragmatic hernia, fractures, cervical-rib or other bony deformity. Electromyography, conducted on postnatal day 2, documented fibrillation potentials in the deltoid and biceps with sparing of the abductor digiti minimi, confirming an in utero injury of the upper brachial plexus. Magnetic resonance imaging revealed a homogenously enhancing cervical mass centered over the apex of the left lung. There was caudad displacement and apparent encasement of the brachial plexus, but no evidence of traumatic nerve-root avulsion (Fig 2). Urinary metanephrines and serum catecholamines were not elevated. An open biopsy was undertaken through the posterior triangle, 11 days after birth. The diagnosis of infantile myofibromatosis was rendered intraoperatively (Fig 3), and no further debulking was attempted. Given the benign natural history of the disease, no adjuvant chemotherapy or radiation therapy was recommended. The postoperative ventilatory wean
From the *Neurosurgery Service, Massachusetts General Hospital, Boston, Massachusetts; †Department of Obstetrics and Gynecology, Creighton University Medical Center, Omaha, Nebraska; and ‡ Department of Pathology and §Pediatric Neurology Service, Massachusetts General Hospital, Boston, Massachusetts.
Communications should be addressed to: Dr. Tierney; Neurosurgery Service, Massachusetts General Hospital; 55 Fruit Street, White 502; Boston, MA 02114. E-mail: [email protected] Received December 3, 2007; accepted June 10, 2008.
Most injuries to the neonatal brachial plexus occur acutely at birth, and are iatrogenic in origin. However, when weakness is accompanied by atrophy, nontraumatic etiologies should be considered. The differential diagnosis of chronic congenital brachial plexopathy includes cervical bone malformations, humeral osteomyelitis, varicella, and compression from various types of infantile tumors. An illustrative male infant delivered at 37 weeks of gestation with wasted musculature of the left upper arm, ipsilateral Horner’s syndrome, and a hemidiaphragm is presented. On further examination, this patient manifested an underlying cervical tumor compressing the brachial plexus. Diagnostic steps leading to the pathologic identification of a solitary cervical myofibroma included physical examination, electromyography, radiographic imaging, and open biopsy. This report emphasizes the importance of differentiating acute from chronic congenital plexus palsy and of recognizing the possibility that infection or neoplasm may underlie the latter. © 2008 by Elsevier Inc. All rights reserved.
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© 2008 by Elsevier Inc. All rights reserved. doi:10.1016/j.pediatrneurol.2008.06.009 ● 0887-8994/08/$—see front matter
Figure 1. Chest x-ray obtained on postnatal day 1. Left hemidiaphragm is clearly elevated, without herniation of abdominal contents. No bony defects are evident. The left arm demonstrates a classic “waiter’s tip.” was successful only after diaphragmatic plication. The patient was then discharged home in good condition, with no further respiratory distress or failure to thrive. Full informed consent to publish this case was obtained from the patient’s mother, his legal guardian.
Discussion Neonatal brachial plexus palsy was first described in the mid-18th century by the British obstetrician William
Figure 2. Preoperative T1-weighted coronal section with contrast indicates a homogenously enhancing 2 ⫻ 2 cm left extra-axial cervical mass with indistinct borders.
Figure 3. Low-power (hematoxylin-and-eosin stain; original magnification ⫻2) image of infantile myofibroma exhibits well-defined margins. Higher-power inset (hematoxylin-and-eosin stain; original magnification ⫻40) demonstrates spindle-shaped myofibroblasts with eosinophilic cytoplasm.
Smellie, who thought that in utero mechanical forces caused the injury [4], but later authors (e.g., Erb, Duchenne, Dejerine, and Klumpke), whose names became associated with these types of palsy, suggested iatrogenic origins. By far, obstetric birth trauma remains the most common cause of infantile brachial plexus paralysis, but other well-documented etiologies include congenital cervical-bone malformations, humeral osteomyelitis, varicella, and compression from tumors such as hemangioma, infantile sarcoma, teratoma, neuroblastoma, neurofibroma, and rarely, myofibroma [5-7]. A nontraumatic cause underlies up to 10% of all congenital brachial plexus palsies [1,7], and such etiologies should be given careful consideration when acute obstetric injury seems unlikely. When weakness is accompanied by atrophy, as in the present case, the search for occult disease is indicated. Even in the absence of frank atrophy, early electrodiagnostic studies provide a safe, simple, and inexpensive tool for excluding acute obstetric injury [8]. Magnetic resonance imaging can definitively exclude traumatic pseudomenigocele, and localize soft-tissue masses that compress or invade the brachial plexus. In this age group, neuroblastoma is one of the more common cervical tumors. It cannot be reliably differentiated from non-amine precursor uptake and decarboxylation tumors radiographically, and catecholamine levels should be checked before surgery to avoid paroxysmal hypertension. Biopsy in the present case definitively established the diagnosis of infantile myofibromatosis, a relatively rare but benign congenital tumor. The natural history of myofibromas usually follows a regressive course, to complete involution within months [5,9,10], suggesting that minimal tumor debulking may be
Tierney et al: Solitary Cervical Myofibroma 277
undertaken when progressive or life-threatening deficits are absent and the intraoperative diagnosis is certain. Conclusions Neonatal brachial plexus palsy is usually caused by acute iatrogenic injury at birth. When accompanied by muscle atrophy or early fibrillation potentials, nontraumatic etiologies should be considered. Treatable conditions such as infection or tumor may underlie chronic neonatal brachial plexopathy. References [1] Evans-Jones G, Kay SP, Weindling AM, et al. Congenital brachial palsy: Incidence, causes, and outcome in the United Kingdom and Republic of Ireland. Arch Dis Child Fetal Neonatal Ed 2003;88:F185-9. [2] Mehta SH, Blackwell SC, Bujold E, Sokol RJ. What factors are associated with neonatal injury following shoulder dystocia? J Perinatol 2006;26:85-8.
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[3] Kirjavainen M, Remes V, Peltonen J, et al. Long-term results of surgery for brachial plexus birth palsy. J Bone Joint Surg [Am] 2007;89:18-26. [4] Smellie W. Collection of preternatural cases and observations in midwifery: Compleating the design of illustrating his first volume on that subject, 3rd ed. London: D. Wilson & T. Durham, 1764:506-7. [5] Boman F, Foliguet B, Metaizeau JP, Olive D, Rauber G. Myofibromatosis in children. Histopathologic and ultrastructural study of a localized form with a spontaneously regressive course. Ann Pathol 1984;4:211-6. [6] Stewart RE, Grossman DM, Shulkin BL, Shapiro B. Iodine-131 metaiodobenzylguanidine uptake in infantile myofibromatosis. Clin Nucl Med 1989;14:344-6. [7] Alfonso I, Alfonso DT, Papazian O. Focal upper extremity neuropathy in neonates. Semin Pediatr Neurol 2000;7:4-14. [8] Pitt M, Vredeveld JW. The role of electromyography in the management of the brachial plexus palsy of the newborn. Clin Neurophysiol 2005;116:1756-61. [9] Stout AP. Juvenile fibromatosis. Cancer 1954;7:953-78. [10] Chung EB, Enzinger FM. Infantile myofibromatosis. Cancer 1981;48:1807-18.
matic cause of neonatal brachial plexus palsy. Pediatr Neurol 2008;39:276-278.
Introduction Approximately 1 in every 2,000 neonates is born with an upper brachial plexus palsy [1-3]. Although iatrogenic birth trauma underlies the majority of these cases, nontraumatic etiologies should be considered when atrophy and fibrillation potentials are present at birth. This case report provides the illustrative example of a male infant born with ipsilateral injuries to the upper brachial plexus, sympathetic chain, and phrenic nerve who was found on further evaluation to manifest an underlying cervical tumor. Case Report
Tierney TS, Tierney BJ, Rosenberg AE, Krishnamoorthy KS, Butler WE. Infantile myofibromatosis: A nontrau-
Prenatal ultrasound at 34 weeks of gestation revealed an elevated left hemidiaphragm in a male fetus. An uncomplicated, elective cesarean section was performed at 37 weeks of gestation in anticipation of respiratory distress. However, the Apgar scores at 1 and 5 minutes were 7 and 8, and he did not require immediate ventilatory support. Left ptosis, anisocoria, and a flaccid left upper extremity prompted transfer to a tertiary referral hospital. Palpation of the limb revealed a concave glenohumeral joint space secondary to wasting of the deltoid and biceps, but without evidence of subluxation or fracture. The infant’s grip was preserved, and his hand was warm. No other obvious deformity or cutaneous stigmata indicative of a phakomatosis, shingles, or hemangioma were evident. He exhibited a good anal wink and no unusual leg reflexes to suggest a long-tract abnormality. Apart from Horner’s syndrome and the upper brachial plexus paralysis, the rest of the examination was unremarkable. In addition to the obvious hemidiaphragm elevation, a chest x-ray performed at admission revealed an internally rotated left forearm with flexion of the wrist and fingers (Fig 1), but no congenital diaphragmatic hernia, fractures, cervical-rib or other bony deformity. Electromyography, conducted on postnatal day 2, documented fibrillation potentials in the deltoid and biceps with sparing of the abductor digiti minimi, confirming an in utero injury of the upper brachial plexus. Magnetic resonance imaging revealed a homogenously enhancing cervical mass centered over the apex of the left lung. There was caudad displacement and apparent encasement of the brachial plexus, but no evidence of traumatic nerve-root avulsion (Fig 2). Urinary metanephrines and serum catecholamines were not elevated. An open biopsy was undertaken through the posterior triangle, 11 days after birth. The diagnosis of infantile myofibromatosis was rendered intraoperatively (Fig 3), and no further debulking was attempted. Given the benign natural history of the disease, no adjuvant chemotherapy or radiation therapy was recommended. The postoperative ventilatory wean
From the *Neurosurgery Service, Massachusetts General Hospital, Boston, Massachusetts; †Department of Obstetrics and Gynecology, Creighton University Medical Center, Omaha, Nebraska; and ‡ Department of Pathology and §Pediatric Neurology Service, Massachusetts General Hospital, Boston, Massachusetts.
Communications should be addressed to: Dr. Tierney; Neurosurgery Service, Massachusetts General Hospital; 55 Fruit Street, White 502; Boston, MA 02114. E-mail: [email protected] Received December 3, 2007; accepted June 10, 2008.
Most injuries to the neonatal brachial plexus occur acutely at birth, and are iatrogenic in origin. However, when weakness is accompanied by atrophy, nontraumatic etiologies should be considered. The differential diagnosis of chronic congenital brachial plexopathy includes cervical bone malformations, humeral osteomyelitis, varicella, and compression from various types of infantile tumors. An illustrative male infant delivered at 37 weeks of gestation with wasted musculature of the left upper arm, ipsilateral Horner’s syndrome, and a hemidiaphragm is presented. On further examination, this patient manifested an underlying cervical tumor compressing the brachial plexus. Diagnostic steps leading to the pathologic identification of a solitary cervical myofibroma included physical examination, electromyography, radiographic imaging, and open biopsy. This report emphasizes the importance of differentiating acute from chronic congenital plexus palsy and of recognizing the possibility that infection or neoplasm may underlie the latter. © 2008 by Elsevier Inc. All rights reserved.
276
PEDIATRIC NEUROLOGY
Vol. 39 No. 4
© 2008 by Elsevier Inc. All rights reserved. doi:10.1016/j.pediatrneurol.2008.06.009 ● 0887-8994/08/$—see front matter
Figure 1. Chest x-ray obtained on postnatal day 1. Left hemidiaphragm is clearly elevated, without herniation of abdominal contents. No bony defects are evident. The left arm demonstrates a classic “waiter’s tip.” was successful only after diaphragmatic plication. The patient was then discharged home in good condition, with no further respiratory distress or failure to thrive. Full informed consent to publish this case was obtained from the patient’s mother, his legal guardian.
Discussion Neonatal brachial plexus palsy was first described in the mid-18th century by the British obstetrician William
Figure 2. Preoperative T1-weighted coronal section with contrast indicates a homogenously enhancing 2 ⫻ 2 cm left extra-axial cervical mass with indistinct borders.
Figure 3. Low-power (hematoxylin-and-eosin stain; original magnification ⫻2) image of infantile myofibroma exhibits well-defined margins. Higher-power inset (hematoxylin-and-eosin stain; original magnification ⫻40) demonstrates spindle-shaped myofibroblasts with eosinophilic cytoplasm.
Smellie, who thought that in utero mechanical forces caused the injury [4], but later authors (e.g., Erb, Duchenne, Dejerine, and Klumpke), whose names became associated with these types of palsy, suggested iatrogenic origins. By far, obstetric birth trauma remains the most common cause of infantile brachial plexus paralysis, but other well-documented etiologies include congenital cervical-bone malformations, humeral osteomyelitis, varicella, and compression from tumors such as hemangioma, infantile sarcoma, teratoma, neuroblastoma, neurofibroma, and rarely, myofibroma [5-7]. A nontraumatic cause underlies up to 10% of all congenital brachial plexus palsies [1,7], and such etiologies should be given careful consideration when acute obstetric injury seems unlikely. When weakness is accompanied by atrophy, as in the present case, the search for occult disease is indicated. Even in the absence of frank atrophy, early electrodiagnostic studies provide a safe, simple, and inexpensive tool for excluding acute obstetric injury [8]. Magnetic resonance imaging can definitively exclude traumatic pseudomenigocele, and localize soft-tissue masses that compress or invade the brachial plexus. In this age group, neuroblastoma is one of the more common cervical tumors. It cannot be reliably differentiated from non-amine precursor uptake and decarboxylation tumors radiographically, and catecholamine levels should be checked before surgery to avoid paroxysmal hypertension. Biopsy in the present case definitively established the diagnosis of infantile myofibromatosis, a relatively rare but benign congenital tumor. The natural history of myofibromas usually follows a regressive course, to complete involution within months [5,9,10], suggesting that minimal tumor debulking may be
Tierney et al: Solitary Cervical Myofibroma 277
undertaken when progressive or life-threatening deficits are absent and the intraoperative diagnosis is certain. Conclusions Neonatal brachial plexus palsy is usually caused by acute iatrogenic injury at birth. When accompanied by muscle atrophy or early fibrillation potentials, nontraumatic etiologies should be considered. Treatable conditions such as infection or tumor may underlie chronic neonatal brachial plexopathy. References [1] Evans-Jones G, Kay SP, Weindling AM, et al. Congenital brachial palsy: Incidence, causes, and outcome in the United Kingdom and Republic of Ireland. Arch Dis Child Fetal Neonatal Ed 2003;88:F185-9. [2] Mehta SH, Blackwell SC, Bujold E, Sokol RJ. What factors are associated with neonatal injury following shoulder dystocia? J Perinatol 2006;26:85-8.
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[3] Kirjavainen M, Remes V, Peltonen J, et al. Long-term results of surgery for brachial plexus birth palsy. J Bone Joint Surg [Am] 2007;89:18-26. [4] Smellie W. Collection of preternatural cases and observations in midwifery: Compleating the design of illustrating his first volume on that subject, 3rd ed. London: D. Wilson & T. Durham, 1764:506-7. [5] Boman F, Foliguet B, Metaizeau JP, Olive D, Rauber G. Myofibromatosis in children. Histopathologic and ultrastructural study of a localized form with a spontaneously regressive course. Ann Pathol 1984;4:211-6. [6] Stewart RE, Grossman DM, Shulkin BL, Shapiro B. Iodine-131 metaiodobenzylguanidine uptake in infantile myofibromatosis. Clin Nucl Med 1989;14:344-6. [7] Alfonso I, Alfonso DT, Papazian O. Focal upper extremity neuropathy in neonates. Semin Pediatr Neurol 2000;7:4-14. [8] Pitt M, Vredeveld JW. The role of electromyography in the management of the brachial plexus palsy of the newborn. Clin Neurophysiol 2005;116:1756-61. [9] Stout AP. Juvenile fibromatosis. Cancer 1954;7:953-78. [10] Chung EB, Enzinger FM. Infantile myofibromatosis. Cancer 1981;48:1807-18.