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MRI findings of retrobulbar myxoma — a case report
Journal of Clinical Imaging 24 (2000) 81 ± 83
MRI findings of retrobulbar myxoma Ð a case report N.B.S. Mani, S. Shankar, Paramjeet Singh*, N. Khandelwal, S. Suri Department of Radiodiagnosis and Imaging, PGIMER, Chandigarh, India Received 1 December 1999; accepted 30 May 2000
Abstract Myxomas are benign soft tissue neoplasms, which usually involve the heart, skin and subcutaneous tissues, and rarely the ocular adnexa. We present a rare case of orbital myxoma with magnetic resonance imaging (MRI) findings and a review of the literature. D 2000 Elsevier Science Inc. All rights reserved. Keywords: Myxoma; Orbit; MRI
1. Introduction Myxomas are benign soft tissue neoplasms presumably originating from pleuripotential embryonal mesenchymal cells, which develop along fibroblast cell lines that produce excess hyaluronic acid instead of collagen [1]. The heart, skin and subcutaneous tissues, skeletal muscle, bone and ocular adnexa are usually involved. Among the ocular adnexa, involvement of the eyelid is commonest [1,2]. Conjunctival and orbital myxomas are very rare with only a few case reports in the English literature. We present a case of retrobulbar myxoma and its magnetic resonance imaging (MRI) findings. To our knowledge, the MRI findings of orbital myxoma have not been described before. 2. Case report A 10-year-old boy presented with a 3-month history of swelling around the right eye and upper cheek with mild proptosis. Significant past history included removal of a mass lesion around the right lateral rectus muscle 2 years ago. A diagnosis of myxoma was given although the histopathology slides were not available for review. The patient remained asymptomatic for a year after which he developed an insidious onset of swelling in the periorbital
* Corresponding author. House No. 157, Sector 16, Chandigarh, 160016 India. Tel.: +91-172-543-169. E-mail address: [email protected] (P. Singh).
region. Apart from mild diplopia, there was no history of any pain, visual impairment or restriction of eye movements. There was no neurological deficit. The exophthalmos was nonpulsatile, there was no papilledema or optic atrophy. Systemic examination did not reveal any abnormality. A specific search was made for any associated cutaneous lesions, cardiac tumors or endocrine abnormality in view of the previous diagnosis of myxoma. The blood, liver function, and renal function tests were within normal limits. Computed tomography (CT) scanning revealed a welldefined, homogenously isodense retrobulbar mass lesion inseparable from the lateral rectus and optic nerve. Bony defect of the previous operation was noted. There was minimal destruction of the lateral wall of the orbit. MRI of the orbit (multiplanar T1 spin echo, T2 fast spin echo, and Gadiodamide enhanced T1 spin echo sequences performed on a 1.5-T MR machine, Siemens Vision Plus, Erlangen, Germany) revealed a well-defined, lobulated, intraconal retrobulbar mass in the right orbit causing indentation of the globe and infero-lateral proptosis. It extended up to the orbital apex without any intracranial extension and through the inferior orbital fissure into the pterygopalatine fossa. There was erosion of the lateral wall of the orbit with infratemporal extension. The optic nerve was deviated to the left side. The lesion appeared hypointense on T1-weighted images (Fig. 1), and bright on T2weighted images (Fig. 2). No contrast enhancement was seen within the tumor (Fig. 3). The patient underwent exenteration of the right orbit with removal of the sphenoid and posterolateral maxillary wall. Pathological examination of the excised specimen revealed
0899-7071/00/$ ± see front matter D 2000 Elsevier Science Inc. All rights reserved. PII: S 0 8 9 9 - 7 0 7 1 ( 0 0 ) 0 0 1 7 8 - 9
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N.B.S. Mani et al. / Journal of Clinical Imaging 24 (2000) 81±83
Fig. 1. Axial T1 weighted sequence reveals a hypointense mass in the retrobulbar region with indentation of the posterior aspect of the globe and proptosis. The optic nerve is displaced medially.
a nonencapsulated tumor of soft elastic consistency with interdigitations between the orbital fat and the extraocular muscle. Histologic examination revealed loosely arranged spindle cells in abundant myxoid stroma, crossed by thin reticular fibres. The vascular component was scarce without a plexiform aspect and there was no perivascular arrangement of cells. 3. Discussion In 1863, Virchow first proposed the term ``myxoma'' to define a neoplastic lesion similar to Wharton's jelly of the umbilical cord. The definitive criteria for recognizing the tumor were given by Stout in 1948 [3]. Myxoma is an uncommon benign soft tissue neoplasm with a predilection for the heart, skin and skeletal muscle.
Fig. 2. Axial T2-weighted sequence at a slightly inferior level shows the mass as a heterogenously hyperintense lesion with extension along the medial aspect of the optic nerve. Note is made of an incidental arachnoid cyst in the anterior left middle cranial fossa.
Fig. 3. Sagittal post contrast T1-weighted image shows no enhancement of the neoplasm.
The histological diagnosis of myxoma is based on the presence of characteristic stellate, round or fused cells in abundant mucoid stroma and exclusion of other lesion, which can show myxomatous areas. Apart from the absence of histological signs of malignancy, the hypovascularity of the tumor and marked extension of myxoid areas are the hallmarks of the lesion [4]. Myxomas of the ocular adnexa are very rare and have been reported to occur in the eyelids, either as a solitary lesion [5] or in association with ``Carney's complex'' [6]; in the conjunctiva [7], orbital bones [8], and orbit [9,10]. Krueger et al. [9] reported a case of retrobulbar orbital myxoma, which was detected by ultrasonography (US). US also played a great role in the selection of the operative approach in that case. The role of imaging in orbital masses is to assess the size, location, and extent of the tumor and to narrow down the differential diagnosis by taking into account the imaging and clinical characteristics [11]. MRI of the orbit, with its superior soft tissue contrast and multiplanar capability best evaluates the tumors of the orbit, optic nerve, and optic pathway. MRI findings of soft tissue myxoma have been described before and they usually show a low-signal intensity on T1-weighted images and appear bright on T2weighted images [12]. This finding has been attributed to the excessive amount of mucoid ground substance in the myxoid lesions. Our case also showed similar signal intensities on standard spin-echo images. However, higher signal intensity on T1-weighted images and lower signal intensity on T2-weighted images can also be seen, depending on the viscosity of the mucoid material or other differences in the protein content [13]. Gadiodamideenhanced images did not reveal any enhancement of the mass lesion in our patient. This was in keeping with the
N.B.S. Mani et al. / Journal of Clinical Imaging 24 (2000) 81±83
histologic finding of a poorly vascularised lesion as is true of myxomas. Thus, although there are no characteristic features on MRI, the unusual feature of no contrast enhancement, coupled with awareness of the lesion may aid in a preoperative diagnosis. It is important to look for any associated cutaneous myxomas, recurrent tumors, skin pigmentation or endocrine overactivity in such patients, especially the young, as it may lead to the detection of cardiac myxomas also [6]. Since myxoma often presents as an infiltrating growth and recurrences, surgical extirpation of the tumor should be as complete as possible. Postoperative follow-up is essential to detect recurrent tumor and other, as yet clinically undetectable myxomas [14]. References [1] Kyriakos M. Tumors and tumorlike conditions of the soft tissue. 9th ed. In: Kissane JM, editor. Anderson's Pathology. St Louis: Mosby, 1990. pp. 1838 ± 928. [2] Kennedy RH, Waller PR, Carney JA. Ocular pigmented spots and eyelid myxomas. Am J Ophthalmol 1987;104:533 ± 8.
83
[3] Stout AP. Myxoma or tumor of primitive mesenchyme. Ann Surg 1948;127:706 ± 19. [4] Enzinger FM, Weiss SW. Soft Tissue Tumors 3rd edn., (Vol. 2). St Louis: Mosby, 1995. pp. 1039 ± 66. [5] Town AE. Myxoma of the lower eyelid. Am J Ophthalmol 1945;28: 68 ± 9. [6] Carney JA, Gordon H, Carpenter PC, Shenoy BV, Go VLW. The complex of myxomas, spotty pigmentation and endocrine overactivity. Medicine 1985;65:270 ± 83. [7] Patrinely JR, Green WR. Conjunctival myxoma: a clinico-pathologic study of four cases and a review of the literature. Arch Ophthalmol 1983;101:1416 ± 20. [8] Candy EJ, Miller NR, Carson BS. Myxoma of bone involving orbit. Arch Ophthalmol 1991;10:919 ± 20. [9] Krueger EG, Polifrone JC, Baum G. Retrobulbar orbital myxoma and its detection by ultrasonography: a case report. J Neurosurg 1967;26:87 ± 91. [10] Blegvad O. Myxoma of the orbit. Acta Ophthalmol (Copenhagen) 1944;22:131 ± 40. [11] Koeller KK, Smirniotopoulos JG. Orbital masses. Semin Ultrasound CT MRI 1988;19(3):272 ± 91. [12] Peterson KK, Renfrew DL, Feddersen RM, Buckwalter JA, ElKhoury GY. Magnetic resonance imaging of myxoid containing tumors. Skeletal Radiol 1991;20:245 ± 50. [13] Kawai T, Kishino M, Fuchihata H. MR images of a maxillary myxoma. AJR Am J Roentgeol 1996;167:1342 ± 4. [14] Court-Payen M, Ingemann JL, Bjerregaard B, Schwarz LG, Skjoldbye B. Intramuscular myxoma and fibrous dysplasia of bone Ð Mazabraud's syndrome. A case report. Acta Radiol 1997;38(3):368 ± 71.
MRI findings of retrobulbar myxoma Ð a case report N.B.S. Mani, S. Shankar, Paramjeet Singh*, N. Khandelwal, S. Suri Department of Radiodiagnosis and Imaging, PGIMER, Chandigarh, India Received 1 December 1999; accepted 30 May 2000
Abstract Myxomas are benign soft tissue neoplasms, which usually involve the heart, skin and subcutaneous tissues, and rarely the ocular adnexa. We present a rare case of orbital myxoma with magnetic resonance imaging (MRI) findings and a review of the literature. D 2000 Elsevier Science Inc. All rights reserved. Keywords: Myxoma; Orbit; MRI
1. Introduction Myxomas are benign soft tissue neoplasms presumably originating from pleuripotential embryonal mesenchymal cells, which develop along fibroblast cell lines that produce excess hyaluronic acid instead of collagen [1]. The heart, skin and subcutaneous tissues, skeletal muscle, bone and ocular adnexa are usually involved. Among the ocular adnexa, involvement of the eyelid is commonest [1,2]. Conjunctival and orbital myxomas are very rare with only a few case reports in the English literature. We present a case of retrobulbar myxoma and its magnetic resonance imaging (MRI) findings. To our knowledge, the MRI findings of orbital myxoma have not been described before. 2. Case report A 10-year-old boy presented with a 3-month history of swelling around the right eye and upper cheek with mild proptosis. Significant past history included removal of a mass lesion around the right lateral rectus muscle 2 years ago. A diagnosis of myxoma was given although the histopathology slides were not available for review. The patient remained asymptomatic for a year after which he developed an insidious onset of swelling in the periorbital
* Corresponding author. House No. 157, Sector 16, Chandigarh, 160016 India. Tel.: +91-172-543-169. E-mail address: [email protected] (P. Singh).
region. Apart from mild diplopia, there was no history of any pain, visual impairment or restriction of eye movements. There was no neurological deficit. The exophthalmos was nonpulsatile, there was no papilledema or optic atrophy. Systemic examination did not reveal any abnormality. A specific search was made for any associated cutaneous lesions, cardiac tumors or endocrine abnormality in view of the previous diagnosis of myxoma. The blood, liver function, and renal function tests were within normal limits. Computed tomography (CT) scanning revealed a welldefined, homogenously isodense retrobulbar mass lesion inseparable from the lateral rectus and optic nerve. Bony defect of the previous operation was noted. There was minimal destruction of the lateral wall of the orbit. MRI of the orbit (multiplanar T1 spin echo, T2 fast spin echo, and Gadiodamide enhanced T1 spin echo sequences performed on a 1.5-T MR machine, Siemens Vision Plus, Erlangen, Germany) revealed a well-defined, lobulated, intraconal retrobulbar mass in the right orbit causing indentation of the globe and infero-lateral proptosis. It extended up to the orbital apex without any intracranial extension and through the inferior orbital fissure into the pterygopalatine fossa. There was erosion of the lateral wall of the orbit with infratemporal extension. The optic nerve was deviated to the left side. The lesion appeared hypointense on T1-weighted images (Fig. 1), and bright on T2weighted images (Fig. 2). No contrast enhancement was seen within the tumor (Fig. 3). The patient underwent exenteration of the right orbit with removal of the sphenoid and posterolateral maxillary wall. Pathological examination of the excised specimen revealed
0899-7071/00/$ ± see front matter D 2000 Elsevier Science Inc. All rights reserved. PII: S 0 8 9 9 - 7 0 7 1 ( 0 0 ) 0 0 1 7 8 - 9
82
N.B.S. Mani et al. / Journal of Clinical Imaging 24 (2000) 81±83
Fig. 1. Axial T1 weighted sequence reveals a hypointense mass in the retrobulbar region with indentation of the posterior aspect of the globe and proptosis. The optic nerve is displaced medially.
a nonencapsulated tumor of soft elastic consistency with interdigitations between the orbital fat and the extraocular muscle. Histologic examination revealed loosely arranged spindle cells in abundant myxoid stroma, crossed by thin reticular fibres. The vascular component was scarce without a plexiform aspect and there was no perivascular arrangement of cells. 3. Discussion In 1863, Virchow first proposed the term ``myxoma'' to define a neoplastic lesion similar to Wharton's jelly of the umbilical cord. The definitive criteria for recognizing the tumor were given by Stout in 1948 [3]. Myxoma is an uncommon benign soft tissue neoplasm with a predilection for the heart, skin and skeletal muscle.
Fig. 2. Axial T2-weighted sequence at a slightly inferior level shows the mass as a heterogenously hyperintense lesion with extension along the medial aspect of the optic nerve. Note is made of an incidental arachnoid cyst in the anterior left middle cranial fossa.
Fig. 3. Sagittal post contrast T1-weighted image shows no enhancement of the neoplasm.
The histological diagnosis of myxoma is based on the presence of characteristic stellate, round or fused cells in abundant mucoid stroma and exclusion of other lesion, which can show myxomatous areas. Apart from the absence of histological signs of malignancy, the hypovascularity of the tumor and marked extension of myxoid areas are the hallmarks of the lesion [4]. Myxomas of the ocular adnexa are very rare and have been reported to occur in the eyelids, either as a solitary lesion [5] or in association with ``Carney's complex'' [6]; in the conjunctiva [7], orbital bones [8], and orbit [9,10]. Krueger et al. [9] reported a case of retrobulbar orbital myxoma, which was detected by ultrasonography (US). US also played a great role in the selection of the operative approach in that case. The role of imaging in orbital masses is to assess the size, location, and extent of the tumor and to narrow down the differential diagnosis by taking into account the imaging and clinical characteristics [11]. MRI of the orbit, with its superior soft tissue contrast and multiplanar capability best evaluates the tumors of the orbit, optic nerve, and optic pathway. MRI findings of soft tissue myxoma have been described before and they usually show a low-signal intensity on T1-weighted images and appear bright on T2weighted images [12]. This finding has been attributed to the excessive amount of mucoid ground substance in the myxoid lesions. Our case also showed similar signal intensities on standard spin-echo images. However, higher signal intensity on T1-weighted images and lower signal intensity on T2-weighted images can also be seen, depending on the viscosity of the mucoid material or other differences in the protein content [13]. Gadiodamideenhanced images did not reveal any enhancement of the mass lesion in our patient. This was in keeping with the
N.B.S. Mani et al. / Journal of Clinical Imaging 24 (2000) 81±83
histologic finding of a poorly vascularised lesion as is true of myxomas. Thus, although there are no characteristic features on MRI, the unusual feature of no contrast enhancement, coupled with awareness of the lesion may aid in a preoperative diagnosis. It is important to look for any associated cutaneous myxomas, recurrent tumors, skin pigmentation or endocrine overactivity in such patients, especially the young, as it may lead to the detection of cardiac myxomas also [6]. Since myxoma often presents as an infiltrating growth and recurrences, surgical extirpation of the tumor should be as complete as possible. Postoperative follow-up is essential to detect recurrent tumor and other, as yet clinically undetectable myxomas [14]. References [1] Kyriakos M. Tumors and tumorlike conditions of the soft tissue. 9th ed. In: Kissane JM, editor. Anderson's Pathology. St Louis: Mosby, 1990. pp. 1838 ± 928. [2] Kennedy RH, Waller PR, Carney JA. Ocular pigmented spots and eyelid myxomas. Am J Ophthalmol 1987;104:533 ± 8.
83
[3] Stout AP. Myxoma or tumor of primitive mesenchyme. Ann Surg 1948;127:706 ± 19. [4] Enzinger FM, Weiss SW. Soft Tissue Tumors 3rd edn., (Vol. 2). St Louis: Mosby, 1995. pp. 1039 ± 66. [5] Town AE. Myxoma of the lower eyelid. Am J Ophthalmol 1945;28: 68 ± 9. [6] Carney JA, Gordon H, Carpenter PC, Shenoy BV, Go VLW. The complex of myxomas, spotty pigmentation and endocrine overactivity. Medicine 1985;65:270 ± 83. [7] Patrinely JR, Green WR. Conjunctival myxoma: a clinico-pathologic study of four cases and a review of the literature. Arch Ophthalmol 1983;101:1416 ± 20. [8] Candy EJ, Miller NR, Carson BS. Myxoma of bone involving orbit. Arch Ophthalmol 1991;10:919 ± 20. [9] Krueger EG, Polifrone JC, Baum G. Retrobulbar orbital myxoma and its detection by ultrasonography: a case report. J Neurosurg 1967;26:87 ± 91. [10] Blegvad O. Myxoma of the orbit. Acta Ophthalmol (Copenhagen) 1944;22:131 ± 40. [11] Koeller KK, Smirniotopoulos JG. Orbital masses. Semin Ultrasound CT MRI 1988;19(3):272 ± 91. [12] Peterson KK, Renfrew DL, Feddersen RM, Buckwalter JA, ElKhoury GY. Magnetic resonance imaging of myxoid containing tumors. Skeletal Radiol 1991;20:245 ± 50. [13] Kawai T, Kishino M, Fuchihata H. MR images of a maxillary myxoma. AJR Am J Roentgeol 1996;167:1342 ± 4. [14] Court-Payen M, Ingemann JL, Bjerregaard B, Schwarz LG, Skjoldbye B. Intramuscular myxoma and fibrous dysplasia of bone Ð Mazabraud's syndrome. A case report. Acta Radiol 1997;38(3):368 ± 71.