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Osteochondroma of the trochlea presenting as acquired Brown syndrome: A case report
Osteochondroma of the trochlea presenting as acquired Brown syndrome: A case report Mohammed R. Talebnejad, MD,a Dara Lankaranian, MD,b Kevin Warrian, MA,b Abbas J. Attarzadeh, MD,a Perikala V. Kumar, MD,c and Majid Farvardin, MDa
The following is a rare observational case report of a 16-year-old boy who presented with acquired Brown syndrome associated with a painless slowly growing mass in the supranasal area of the left eye. Meticulous surgical removal of the mass resulted in recovery of superior oblique muscle function. Histopathology was consistent with osteochondroma of the trochlea. To the knowledge of the authors, this is the first reported case of osteochondroma of the trochlea causing acquired Brown syndrome.
B
rown syndrome is a restrictive strabismus characterized by consistent findings including limitation of elevation in adduction, normal elevation in abduction, a positive forced duction test, and variable additional findings such as hypotropia in primary position, widening of lid fissure, downshoot in adduction, and compensatory head posture.1-3 The following is a report of a rare cause of acquired Brown syndrome and its clinicopathologic findings.
Case Report
FIG 1. Top: The mass is visible in the anterior supranasal area of left orbit. Bottom: Two weeks after surgical excision, a scar is visible in the anterior supranasal area of the orbit and the patient was left with a mild limitation of elevation in adduction.
A 16-year-old boy was seen in a strabismus clinic with the chief complaint of a slowly growing mass in the anterior supranasal area of left orbit associated with recent binocular diplopia in upgaze (Figure 1). There was no history of trauma or radiation to the orbit or any other pertinent positive findings in his history. External examination of the left eye revealed a firm, nodular, nontender, immobile mass without pulsation or changes in the overlying skin. The eyes were orthotropic in primary position and downgaze, but a limitation of elevation in adduction of the left eye in both duction and version testing was noted (Figure 2). Forced duction test was performed and revealed a restriction of elevation in
Author affiliations: aDepartment of Ophthalmology, Shiraz University Medical School, Shiraz, Iran; bThe William and Anna Goldberg Glaucoma Service, Wills Eye Hospital/ Jefferson Medical College, Philadelphia, Pennsylvania; and cDepartment of Pathology, Shiraz University Medical School, Shiraz, Iran This study was done in Khalili Hospital/Shiraz Medical School, Shiraz, Iran. The authors have no financial interest in the material mentioned in the text. Submitted September 30, 2005. Revision accepted January 15, 2007. Published online April 20, 2007. Reprint requests: Dara Lankaranian, MD, Wills Eye Hospital/Jefferson Medical College, 840 Walnut Street, Suite 1140, Philadelphia, PA 19107 (email: lankaranian@ yahoo.com). J AAPOS 2007;11:305-306. Copyright © 2007 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/2007/$35.00 ⫹ 0 doi:10.1016/j.jaapos.2007.01.121
Journal of AAPOS
FIG 2. Ocular deviation before and after operation. Top: Ocular deviation before operation with right eye fixating. Bottom: Ocular deviation after operation with left eye fixating. LHoT, left hypotropia; ORTHO, orthotropia.
adduction of the left eye. No click was heard or felt. Computerized tomography scanning revealed a nonhomogenous mass in the left orbit, which was continuous with the left trochlea and superior oblique tendon (Figure 2). The mass was confined to the anterior supranasal area and unaccompanied by changes in the surrounding bony structures. With the impression of acquired Brown syndrome, exploratory surgery was performed and the tumor was dissected with preservation of tendon and trochlea. Intraoperative forced duction testing after tumor excision became
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Discussion
FIG 3. Noncontrast axial CT scans of orbits. Tumor is visible in anterior left orbit without any surrounding bony changes. Lower left: Gross specimen demonstrating a shiny cartilaginous cup present over the tumor, osteochondroma. Lower right: Histopathology of the tumor demonstrated immature osteoid and cartilaginous tissue with no atypia or abnormal mitosis, osteochondroma, hematoxylin & eosin, ⫻160; ⫻900.
negative. Although the tumor originated from the trochlea, the aberrant mass did not invade the tendon proper. Gross examination of the resected specimen demonstrated a hard bony mass (20 ⫻ 12 ⫻ 10 mm) with a shiny cartilaginous cap (Figure 3). Histopathologic evaluation of the tumor disclosed components of immature osteoid and cartilaginous tissue with no atypia or abnormal mitosis. The osteoid tissue was surrounded by chondrocytes in the form of a cap. The diagnosis of osteochondroma was made based on these findings (Figure 3). Several weeks following surgical removal of the tumor, the left eye’s motility in the field of action of the superior oblique muscle was improved and the forced duction test of the left eye was negative. A negligible limitation of elevation in adduction persisted in extreme upgaze (Figure 2). The patient was followed for more than 4 years after surgery and no changes in extraocular motility were noted on subsequent examinations.
Brown syndrome is a restrictive strabismus, which can be either congenital or acquired. The congenital form can be caused by a wide variety of pathological abnormalities involving the primary tendon, tendon sheath, or tendontrochlea complex.3-5 In contrast, acquired Brown syndrome can be caused by over 20 different pathological conditions that include traumatic, autoimmune, inflammatory, metabolic, neoplastic, infectious, and iatrogenic processes.4 Proper identification of the specific etiology of Brown syndrome is important, as the probability for spontaneous recovery is higher in acquired cases in comparison with the congenital variety. In acquired Brown syndrome, a comprehensive medical history followed by orbital imaging and laboratory studies, where indicated, can be employed to obtain a specific diagnosis.3-5 Treatment depends on the underlying etiology. To our knowledge, this publication is the first reported case of osteochondroma of the trochlea causing acquired Brown syndrome. This case has demonstrated the existence of osteochondroma of the trochlea, a benign orbital tumor that can be successfully treated through meticulous surgical excision. Literature Search Primary and secondary scientific literature were searched using MEDLINE (1950-2006), Exerpta Medica (19502006), OVID, and SCOPUS, using the keywords osteochondroma and Brown syndrome, osteochondroma and SO, osteochondroma and extraocular muscle, and osteochondroma and trochlea. The search was not limited to English language or indexed citations. References 1. Jaensch PA. Paresen der Schragen Heber. Graefes Arch Ophthalmol 1928;121:113. 2. Brown HW. Congenital structural muscle anomalies. In: Allen JH, editor. Strabismus ophthalmic symposium 1. St. Louis (MO): Mosby Year Book, 1950. p. 205. 3. Von Noorden GK, Campus EC. Binocular vision and ocular motility. In: Theory and management of strabismus. 6th ed. St. Louis (MO): Mosby; 2002. p. 466-71. 4. Wright KW. Brown’s syndrome: diagnosis and management. Trans Am Ophthalmol Soc 1999;97:1023-109. 5. Rosenbaum AR, Santiago AP. Clinical strabismus management, principles, and surgical techniques. 1st ed. Philadelphia (PA): W.B.Saunders; 1999. p. 347-54.
Journal of AAPOS
The following is a rare observational case report of a 16-year-old boy who presented with acquired Brown syndrome associated with a painless slowly growing mass in the supranasal area of the left eye. Meticulous surgical removal of the mass resulted in recovery of superior oblique muscle function. Histopathology was consistent with osteochondroma of the trochlea. To the knowledge of the authors, this is the first reported case of osteochondroma of the trochlea causing acquired Brown syndrome.
B
rown syndrome is a restrictive strabismus characterized by consistent findings including limitation of elevation in adduction, normal elevation in abduction, a positive forced duction test, and variable additional findings such as hypotropia in primary position, widening of lid fissure, downshoot in adduction, and compensatory head posture.1-3 The following is a report of a rare cause of acquired Brown syndrome and its clinicopathologic findings.
Case Report
FIG 1. Top: The mass is visible in the anterior supranasal area of left orbit. Bottom: Two weeks after surgical excision, a scar is visible in the anterior supranasal area of the orbit and the patient was left with a mild limitation of elevation in adduction.
A 16-year-old boy was seen in a strabismus clinic with the chief complaint of a slowly growing mass in the anterior supranasal area of left orbit associated with recent binocular diplopia in upgaze (Figure 1). There was no history of trauma or radiation to the orbit or any other pertinent positive findings in his history. External examination of the left eye revealed a firm, nodular, nontender, immobile mass without pulsation or changes in the overlying skin. The eyes were orthotropic in primary position and downgaze, but a limitation of elevation in adduction of the left eye in both duction and version testing was noted (Figure 2). Forced duction test was performed and revealed a restriction of elevation in
Author affiliations: aDepartment of Ophthalmology, Shiraz University Medical School, Shiraz, Iran; bThe William and Anna Goldberg Glaucoma Service, Wills Eye Hospital/ Jefferson Medical College, Philadelphia, Pennsylvania; and cDepartment of Pathology, Shiraz University Medical School, Shiraz, Iran This study was done in Khalili Hospital/Shiraz Medical School, Shiraz, Iran. The authors have no financial interest in the material mentioned in the text. Submitted September 30, 2005. Revision accepted January 15, 2007. Published online April 20, 2007. Reprint requests: Dara Lankaranian, MD, Wills Eye Hospital/Jefferson Medical College, 840 Walnut Street, Suite 1140, Philadelphia, PA 19107 (email: lankaranian@ yahoo.com). J AAPOS 2007;11:305-306. Copyright © 2007 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/2007/$35.00 ⫹ 0 doi:10.1016/j.jaapos.2007.01.121
Journal of AAPOS
FIG 2. Ocular deviation before and after operation. Top: Ocular deviation before operation with right eye fixating. Bottom: Ocular deviation after operation with left eye fixating. LHoT, left hypotropia; ORTHO, orthotropia.
adduction of the left eye. No click was heard or felt. Computerized tomography scanning revealed a nonhomogenous mass in the left orbit, which was continuous with the left trochlea and superior oblique tendon (Figure 2). The mass was confined to the anterior supranasal area and unaccompanied by changes in the surrounding bony structures. With the impression of acquired Brown syndrome, exploratory surgery was performed and the tumor was dissected with preservation of tendon and trochlea. Intraoperative forced duction testing after tumor excision became
305
306
Talebnejad et al
Volume 11 Number 3 / June 2007
Discussion
FIG 3. Noncontrast axial CT scans of orbits. Tumor is visible in anterior left orbit without any surrounding bony changes. Lower left: Gross specimen demonstrating a shiny cartilaginous cup present over the tumor, osteochondroma. Lower right: Histopathology of the tumor demonstrated immature osteoid and cartilaginous tissue with no atypia or abnormal mitosis, osteochondroma, hematoxylin & eosin, ⫻160; ⫻900.
negative. Although the tumor originated from the trochlea, the aberrant mass did not invade the tendon proper. Gross examination of the resected specimen demonstrated a hard bony mass (20 ⫻ 12 ⫻ 10 mm) with a shiny cartilaginous cap (Figure 3). Histopathologic evaluation of the tumor disclosed components of immature osteoid and cartilaginous tissue with no atypia or abnormal mitosis. The osteoid tissue was surrounded by chondrocytes in the form of a cap. The diagnosis of osteochondroma was made based on these findings (Figure 3). Several weeks following surgical removal of the tumor, the left eye’s motility in the field of action of the superior oblique muscle was improved and the forced duction test of the left eye was negative. A negligible limitation of elevation in adduction persisted in extreme upgaze (Figure 2). The patient was followed for more than 4 years after surgery and no changes in extraocular motility were noted on subsequent examinations.
Brown syndrome is a restrictive strabismus, which can be either congenital or acquired. The congenital form can be caused by a wide variety of pathological abnormalities involving the primary tendon, tendon sheath, or tendontrochlea complex.3-5 In contrast, acquired Brown syndrome can be caused by over 20 different pathological conditions that include traumatic, autoimmune, inflammatory, metabolic, neoplastic, infectious, and iatrogenic processes.4 Proper identification of the specific etiology of Brown syndrome is important, as the probability for spontaneous recovery is higher in acquired cases in comparison with the congenital variety. In acquired Brown syndrome, a comprehensive medical history followed by orbital imaging and laboratory studies, where indicated, can be employed to obtain a specific diagnosis.3-5 Treatment depends on the underlying etiology. To our knowledge, this publication is the first reported case of osteochondroma of the trochlea causing acquired Brown syndrome. This case has demonstrated the existence of osteochondroma of the trochlea, a benign orbital tumor that can be successfully treated through meticulous surgical excision. Literature Search Primary and secondary scientific literature were searched using MEDLINE (1950-2006), Exerpta Medica (19502006), OVID, and SCOPUS, using the keywords osteochondroma and Brown syndrome, osteochondroma and SO, osteochondroma and extraocular muscle, and osteochondroma and trochlea. The search was not limited to English language or indexed citations. References 1. Jaensch PA. Paresen der Schragen Heber. Graefes Arch Ophthalmol 1928;121:113. 2. Brown HW. Congenital structural muscle anomalies. In: Allen JH, editor. Strabismus ophthalmic symposium 1. St. Louis (MO): Mosby Year Book, 1950. p. 205. 3. Von Noorden GK, Campus EC. Binocular vision and ocular motility. In: Theory and management of strabismus. 6th ed. St. Louis (MO): Mosby; 2002. p. 466-71. 4. Wright KW. Brown’s syndrome: diagnosis and management. Trans Am Ophthalmol Soc 1999;97:1023-109. 5. Rosenbaum AR, Santiago AP. Clinical strabismus management, principles, and surgical techniques. 1st ed. Philadelphia (PA): W.B.Saunders; 1999. p. 347-54.
Journal of AAPOS