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Medulloblastoma presenting as consecutive esotropia after successful lateral rectus muscle recession for infantile exotropia
Medulloblastoma presenting as consecutive esotropia after successful lateral rectus muscle recession for infantile exotropia Steven E. Rosenberg, MD,a,b Danielle Savitsky Strauss, MD,a Irina Mikolaenko, MD,c and Norman A. Saffra, MD, FACSa,b
Comitant infantile exotropia is a rare entity and is far less common than infantile esotropia. It has been shown to be highly correlated with intracranial pathology. We report a case of a medulloblastoma in a child in whom it presented as an incomitant esotropia after surgical correction for comitant infantile exotropia.
Case Report
A
3-month-old girl was referred to Maimonides Medical Center for evaluation of bilateral alternating exotropia. She was born at 37 weeks’ gestational age weighing 6 lbs 7 oz, with unremarkable birth, perinatal, and developmental histories. Family history included a benign brain tumor in the patient’s aunt. The girl had been born with a large head circumference and underwent intracranial ultrasound to rule out hydrocephalus. Findings of the ultrasound revealed no abnormalities or masses. A physical examination revealed no craniofacial abnormalities. Her vision was central, steady, and maintained bilaterally. Ocular motility testing showed full ductions and versions. Measurement of ocular alignment revealed a comitant exotropia of 45D by Krimsky testing at both distance and near fixation. Primary gaze measurements at near fixation were confirmed by alternate-cover testing. There was no anisocoria or afferent pupillary defect. Cycloplegic refraction showed a latent refractive error of 11.50 D in both eyes. The results of the dilated fundus examination were within normal limits. Part-time, antisuppression occlusive therapy was initiated to prevent amblyopia. At 6 months of age, after two more examinations confirmed the measurements on the first examination, bilateral lateral rectus muscle recessions of 8.0 mm were performed. One month later, the eyes were aligned in primary position, with equal visual acuity bilaterally. Two months postoperatively, the patient developed an incomitant left esotropia. Examination revealed an intermittent esotropia of 25D in primary gaze, upgaze, and downAuthor affiliations: aMaimonides Medical Center, Brooklyn, New York; bNew York Eye and Ear Infirmary, New York, New York; and cNew York University Medical Center, New York Submitted November 8, 2010. Revision accepted May 18, 2011. Reprint requests: Steven E. Rosenberg, MD, The New York Eye and Ear Infirmary, 310 East 14th Street, 2nd Floor, South Building New York, NY 10003 (email: [email protected]). J AAPOS 2011;15:499-501. Copyright Ó 2011 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 doi:10.1016/j.jaapos.2011.05.018
Journal of AAPOS
gaze. The esotropia measured 20D in right gaze and 45D in left gaze. The differential diagnosis at this time included a new left abducens nerve palsy or a slipped left lateral rectus muscle. Magnetic resonance imaging (MRI) with contrast revealed a 2.3 cm enhancing, well-circumscribed mass in the left superior cerebellar region with mass effect on the left posterior midbrain, upper pons, and fourth ventricle (Figure 1A-B). Pediatric neurosurgery consultation recommended excision of the mass. A suboccipital craniotomy was performed and the pathology evaluation of the excised lesion confirmed medulloblastoma (Figure 2). The patient received a full course of chemotherapy. At 23 months of age, she underwent an uneventful second strabismus surgery to correct the persistent esotropia. At 3 years of age, vision was central, steady, and maintained in both eyes, with alternating fixation. Evaluation of her ocular alignment revealed an exophoria of 2D at near fixation and a comitant, intermittent esotropia of 8D at distance fixation, with trace dissociated vertical deviation that was only manifest during alternate cover testing. On testing of her near point of convergence, she was able to converge to the tip of her nose. She had full ductions and versions. Pupils remained normal.
Discussion Infantile exotropia has been defined as a large-angle, constant strabismus that presents by 6 months of age in an otherwise healthy child.1,2 The prevalence of exotropia is approximately 1.0% in children younger than 11 years of age.3 Infantile exotropia is far less common than other childhood exotropias. Baeteman and colleagues4 found that 61.7% of primary exotropia cases were associated with pathological MRI findings, including white matter injury, gray matter injury, and a thin corpus callosum. In a case series of patients from a university hospital–based practice, Hunter and Ellis5 found that 67% of patients with exotropia who presented in the first year of life had associated ocular or systemic abnormalities. To our knowledge, this case is the first reported one of comitant infantile exotropia as the presenting symptom of a brain tumor. Neuroimaging for comitant, infantile strabismus has not been used routinely on patients preoperatively. Given the high correlation of infantile exotropia with intracranial pathology and other ocular and systemic abnormalities and the low incidence of comitant infantile exotropia, MRI may be beneficial to rule out intracranial pathology.1-5 In addition, MRI may show the absence or hypoplasia of the extraocular muscles and/or cranial nerves.6 It is unclear
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Rosenberg et al
Volume 15 Number 5 / October 2011
FIG 1. Coronal (A) and axial (B) MRIs demonstrate a wellcircumscribed mass in the left superior cerebellar region.
whether the infantile exotropia in our case was directly related to the medulloblastoma; however, given the size of the tumor and the presentation of the tumor 2 months after surgery, it is suggestive that the tumor existed before surgery and was related to the infantile exotropia. It is possible that had surgical correction not been performed and no neuroimaging obtained, the diagnosis of the abducens
FIG 2. Histopathological sections of the tumor. A, features of desmoplastic/nodular medulloblastoma, with pale nodular areas representing regions of neuronal maturation (hematoxylin-eosin, original magnification 10). B, areas with predominantly desmoplastic pattern and smaller pale nodules as well as areas of conventional medulloblastoma composed of undifferentiated tumor cells with hyperchromatic nuclei with scant cytoplasm and frequent mitoses (hematoxylin-eosin stain, original magnification 20). C, positive staining for neuronal markers and synaptophysin (NeuN immunostain, original magnification 40).
Journal of AAPOS
Volume 15 Number 5 / October 2011 nerve palsy may have been delayed because the exotropia would have appeared to improve. This case shows that the intracranial pathology associated with infantile exotropia may require timely treatment. Because infantile exotropia is uncommon, consideration of neuroimaging before surgical correction in all patients with infantile exotropia, even in those without other signs of intracranial pathology, would not result in many additional MRIs being performed and could lead to more timely treatment of an associated intracranial pathology. A full study of the relative cost and benefits of performing neuroimaging on all patients with a constant infantile exotropia would be helpful though difficult to perform, given the exceedingly low incidence of this condition.
Journal of AAPOS
Rosenberg et al
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References 1. Hunter DG, Kelly JB, Buffenn AN, Ellis FJ. Long-term outcome of uncomplicated infantile exotropia. J AAPOS 2001;5:352-6. 2. Mohney B, Huffaker RK. Common forms of childhood exotropia. Ophthalmology 2003;110:2093-6. 3. Govindan M, Diehl NN, Burke JP. Incidence and types of childhood exotropia: A population-based study. Ophthalmology 2005;112:104-8. 4. Baeteman C, Loudot C, Toesca E, et al. Primary exotropia: Importance of cerebral MRI. J Fr Ophthalm 2008;31:287-94. 5. Hunter DG, Ellis FJ. Prevalence of systemic and ocular disease in infantile exotropia: Comparison with infantile esotropia. Ophthalmology 1999;106:1951-6. 6. Demer JL, Engle EC, Thacker N. High-resolution magnetic resonance imaging demonstrates abnormalities of motor nerves and extraocular muscles in patients with neuropathic strabismus. J AAPOS 2006:135-42.
Comitant infantile exotropia is a rare entity and is far less common than infantile esotropia. It has been shown to be highly correlated with intracranial pathology. We report a case of a medulloblastoma in a child in whom it presented as an incomitant esotropia after surgical correction for comitant infantile exotropia.
Case Report
A
3-month-old girl was referred to Maimonides Medical Center for evaluation of bilateral alternating exotropia. She was born at 37 weeks’ gestational age weighing 6 lbs 7 oz, with unremarkable birth, perinatal, and developmental histories. Family history included a benign brain tumor in the patient’s aunt. The girl had been born with a large head circumference and underwent intracranial ultrasound to rule out hydrocephalus. Findings of the ultrasound revealed no abnormalities or masses. A physical examination revealed no craniofacial abnormalities. Her vision was central, steady, and maintained bilaterally. Ocular motility testing showed full ductions and versions. Measurement of ocular alignment revealed a comitant exotropia of 45D by Krimsky testing at both distance and near fixation. Primary gaze measurements at near fixation were confirmed by alternate-cover testing. There was no anisocoria or afferent pupillary defect. Cycloplegic refraction showed a latent refractive error of 11.50 D in both eyes. The results of the dilated fundus examination were within normal limits. Part-time, antisuppression occlusive therapy was initiated to prevent amblyopia. At 6 months of age, after two more examinations confirmed the measurements on the first examination, bilateral lateral rectus muscle recessions of 8.0 mm were performed. One month later, the eyes were aligned in primary position, with equal visual acuity bilaterally. Two months postoperatively, the patient developed an incomitant left esotropia. Examination revealed an intermittent esotropia of 25D in primary gaze, upgaze, and downAuthor affiliations: aMaimonides Medical Center, Brooklyn, New York; bNew York Eye and Ear Infirmary, New York, New York; and cNew York University Medical Center, New York Submitted November 8, 2010. Revision accepted May 18, 2011. Reprint requests: Steven E. Rosenberg, MD, The New York Eye and Ear Infirmary, 310 East 14th Street, 2nd Floor, South Building New York, NY 10003 (email: [email protected]). J AAPOS 2011;15:499-501. Copyright Ó 2011 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 doi:10.1016/j.jaapos.2011.05.018
Journal of AAPOS
gaze. The esotropia measured 20D in right gaze and 45D in left gaze. The differential diagnosis at this time included a new left abducens nerve palsy or a slipped left lateral rectus muscle. Magnetic resonance imaging (MRI) with contrast revealed a 2.3 cm enhancing, well-circumscribed mass in the left superior cerebellar region with mass effect on the left posterior midbrain, upper pons, and fourth ventricle (Figure 1A-B). Pediatric neurosurgery consultation recommended excision of the mass. A suboccipital craniotomy was performed and the pathology evaluation of the excised lesion confirmed medulloblastoma (Figure 2). The patient received a full course of chemotherapy. At 23 months of age, she underwent an uneventful second strabismus surgery to correct the persistent esotropia. At 3 years of age, vision was central, steady, and maintained in both eyes, with alternating fixation. Evaluation of her ocular alignment revealed an exophoria of 2D at near fixation and a comitant, intermittent esotropia of 8D at distance fixation, with trace dissociated vertical deviation that was only manifest during alternate cover testing. On testing of her near point of convergence, she was able to converge to the tip of her nose. She had full ductions and versions. Pupils remained normal.
Discussion Infantile exotropia has been defined as a large-angle, constant strabismus that presents by 6 months of age in an otherwise healthy child.1,2 The prevalence of exotropia is approximately 1.0% in children younger than 11 years of age.3 Infantile exotropia is far less common than other childhood exotropias. Baeteman and colleagues4 found that 61.7% of primary exotropia cases were associated with pathological MRI findings, including white matter injury, gray matter injury, and a thin corpus callosum. In a case series of patients from a university hospital–based practice, Hunter and Ellis5 found that 67% of patients with exotropia who presented in the first year of life had associated ocular or systemic abnormalities. To our knowledge, this case is the first reported one of comitant infantile exotropia as the presenting symptom of a brain tumor. Neuroimaging for comitant, infantile strabismus has not been used routinely on patients preoperatively. Given the high correlation of infantile exotropia with intracranial pathology and other ocular and systemic abnormalities and the low incidence of comitant infantile exotropia, MRI may be beneficial to rule out intracranial pathology.1-5 In addition, MRI may show the absence or hypoplasia of the extraocular muscles and/or cranial nerves.6 It is unclear
499
500
Rosenberg et al
Volume 15 Number 5 / October 2011
FIG 1. Coronal (A) and axial (B) MRIs demonstrate a wellcircumscribed mass in the left superior cerebellar region.
whether the infantile exotropia in our case was directly related to the medulloblastoma; however, given the size of the tumor and the presentation of the tumor 2 months after surgery, it is suggestive that the tumor existed before surgery and was related to the infantile exotropia. It is possible that had surgical correction not been performed and no neuroimaging obtained, the diagnosis of the abducens
FIG 2. Histopathological sections of the tumor. A, features of desmoplastic/nodular medulloblastoma, with pale nodular areas representing regions of neuronal maturation (hematoxylin-eosin, original magnification 10). B, areas with predominantly desmoplastic pattern and smaller pale nodules as well as areas of conventional medulloblastoma composed of undifferentiated tumor cells with hyperchromatic nuclei with scant cytoplasm and frequent mitoses (hematoxylin-eosin stain, original magnification 20). C, positive staining for neuronal markers and synaptophysin (NeuN immunostain, original magnification 40).
Journal of AAPOS
Volume 15 Number 5 / October 2011 nerve palsy may have been delayed because the exotropia would have appeared to improve. This case shows that the intracranial pathology associated with infantile exotropia may require timely treatment. Because infantile exotropia is uncommon, consideration of neuroimaging before surgical correction in all patients with infantile exotropia, even in those without other signs of intracranial pathology, would not result in many additional MRIs being performed and could lead to more timely treatment of an associated intracranial pathology. A full study of the relative cost and benefits of performing neuroimaging on all patients with a constant infantile exotropia would be helpful though difficult to perform, given the exceedingly low incidence of this condition.
Journal of AAPOS
Rosenberg et al
501
References 1. Hunter DG, Kelly JB, Buffenn AN, Ellis FJ. Long-term outcome of uncomplicated infantile exotropia. J AAPOS 2001;5:352-6. 2. Mohney B, Huffaker RK. Common forms of childhood exotropia. Ophthalmology 2003;110:2093-6. 3. Govindan M, Diehl NN, Burke JP. Incidence and types of childhood exotropia: A population-based study. Ophthalmology 2005;112:104-8. 4. Baeteman C, Loudot C, Toesca E, et al. Primary exotropia: Importance of cerebral MRI. J Fr Ophthalm 2008;31:287-94. 5. Hunter DG, Ellis FJ. Prevalence of systemic and ocular disease in infantile exotropia: Comparison with infantile esotropia. Ophthalmology 1999;106:1951-6. 6. Demer JL, Engle EC, Thacker N. High-resolution magnetic resonance imaging demonstrates abnormalities of motor nerves and extraocular muscles in patients with neuropathic strabismus. J AAPOS 2006:135-42.