Seminars in Ophthalmology, 2015; 30(4): 316–320 ! Informa Healthcare USA, Inc. ISSN: 0882-0538 print / 1744-5205 online DOI: 10.3109/08820538.2013.874471
C ASE REPORT
Orbital Nerve Seath Myxoma with Extraocular Muscle Involvement: A Rare Case Ignacio Rodrı´guez-Un˜a1, Juan A. Troyano-Rivas1, Cristina Gonza´lez-Garcı´a1, Reinaldo Chı´charo-de-Freitas2, Juan J. Ortiz-Zapata3, Luis Ortega-Medina3, Nicola´s Toledano-Ferna´ndez4, and Julia´n Garcı´a-Feijoo1,5 1
Department of Ophthalmology, Hospital Clı´nico San Carlos, Instituto de Investigacio´n Sanitaria del Hospital Clı´nico San Carlos (IdISSC), Madrid, Spain, 2Department of Nuclear Medicine, Hospital Clı´nico San Carlos, Madrid, Spain, 3Department of Anatomic Pathology, Hospital Clı´nico San Carlos, Madrid, Spain, 4Department of Ophthalmology, Hospital Universitario de Fuenlabrada, Fuenlabrada, Spain, and 5Cooperative Research Network on Age-Related Ocular Pathology, Visual and Life Quality, Instituto de Salud Carlos III, Madrid, Spain
ABSTRACT A 66-year-old woman with breast cancer presented with a painless mass in the left orbit. MRI revealed a welldefined intraconal mass in the temporal quadrant of the orbit. Fifteen months later, a further MRI indicated the mass had grown, displacing the left optic nerve and making contact with the lateral rectus muscle, suggesting its possible intramuscular origin. Despite the clinical and radiological characteristics of the lesion and its slow growth, a PET/CT study was developed because of the history of malignant disease. No metabolic activity of the mass or malignant lesion in other locations was observed. After surgical excision, histopathological examination revealed an abundant myxoid matrix with few spindle-shaped cells and no signs of malignancy. The cells were immunopositive for CD34, positive for S-100 protein, and negative for EMA, actin, and CD57. A diagnosis was made of a nerve sheath myxoma. The orbital location of these tumors is extremely rare. Keywords: Benign tumors, immunohistochemistry, nerve sheath myxoma, neurothekeoma, orbital neoplasms
INTRODUCTION
of Madrid, Spain. Care of the patient in this study was in accordance with the Declaration of Helsinki.
Nerve sheath myxoma is an infrequent benign tumor whose origin and classification remain unclear. Although the appearance of a nerve sheath myxoma in the upper limbs and feet is well documented, this tumor is rarely seen in ophthalmologic practice. To date, there is one reported case in the literature of a nerve sheath myxoma involving the orbit1 and a further case of a similar tumor, a neurothekeoma,2 also affecting the orbit. Here, we describe the case of a female patient with a nerve sheath myxoma arising in the orbit and affecting extraocular muscles. To the best of our knowledge, this is the first report of such a tumor affecting this structure. This study was conducted with the approval of the Ethics Committee of the Hospital Clı´nico San Carlos
CASE REPORT A 66-year-old woman was referred to our ophthalmology department because of a painless mass in the left orbit that had been inadvertently detected in a CT scan of the paranasal sinuses. Her medical history included a recent mastectomy and lymph node removal for breast cancer. The CT revealed an intraconal lesion that made tight contact with the lateral rectus (LR) muscle. Our initial radiologic suspicion was a cavernous hemangioma in the orbit because of the frequency of this tumor and its location.
Received 12 June 2013; accepted 8 December 2013; published online 29 January 2014 Correspondence: Ignacio Rodrı´guez-Un˜a, M.D., Department of Ophthalmology, Hospital Clı´nico San Carlos, Avda. Prof. Martin Lagos S/N, 28040 Madrid, Spain. E-mail: [email protected]
316
Orbital Nerve Seath Myxoma 317
FIGURE 1. MRI scan of the orbit at the time of diagnosis showing axial (A) and coronal sections (B, C). (A) Axial T2-weighted MRI image reveals a strongly enhanced intraconal mass in the left orbit, near the optic nerve. (B) Coronal T2-weighted MRI section showing the relationship between the lesion and lateral rectus muscle. Note the imprint of the mass towards the orbital cone interior. (C) In T1-weighted MRI images, the lesion appears as isointense with the muscle.
FIGURE 2. MRI scan of the orbit 15 months after diagnosis. Axial (A) and coronal sections (B, C) reveal the notable size increase of the tumor mass. (A) Axial T2- weighted MRI image shows the mass medially displacing the optic nerve. (B) Coronal T2-weighted MRI and (C) coronal T1-weighted sections in which the mass appears in close contact with the lateral rectus muscle, causing it to bulge and inferomedially displacing the left optic nerve.
Cranial MRI (magnetic resonance imaging) revealed a homogenous well-defined intraconal mass, 1.10 1.15 1.64 cm, in the left orbit (Figure 1). No exophthalmos, ptosis, or ocular motility limitations were noted. Visual acuity in the left eye was 20/60. The rest of the ophthalmologic examination was normal, including a fundus exam and intraocular pressure. A follow-up MRI three months later indicated a similar situation, although in a further MRI at 12 months (Figure 2A), it was observed that the mass had grown (to 1.50 2.18 1.64 cm), displacing the left optic nerve and contacting tightly with the LR muscle, suggesting its intramuscular location (Figures 2B, C), even with muscle fiber bundles crossing the tumor mass (Figure 3). The patient reported no symptoms. At this point, despite the clinical and radiological characteristics of the lesion and its slow growth, we !
2015 Informa Healthcare USA, Inc.
considered the possibility of metastasis from the patient’s breast tumor and undertook a whole-body PET/CT scan (Figure 4). The scan indicated no metabolic activity of the orbital mass and no malignant lesions at other sites. On these grounds and despite the apparent benignity of the lesion, the decision was made with the patient to excise the mass so that a malignancy could be histologically ruled out. We conducted an orbitotomy without osteotomy through a superior eyelid crease incision. The tumor was completely removed and submitted for histopathological examination. The surgical specimen was a white and soft round mass with a maximum diameter of 2.0 cm. This mass was composed of myxoid nodules with sparse cells. These cells were spindle-shaped or stellate admixed with an abundant myxoid matrix; no atypia were observed (Figures 5A, B). Immunohistochemistry revealed that
318 I. Rodrı´guez-Un˜a et al. the cells were positive for CD34 (Figure 5C), positive for S100 protein (Figure 5D), and negative for EMA, actin, and CD57. These findings led to a diagnosis of orbital nerve sheath myxoma. In the one-month follow-up session, the patient was well with no signs of local recurrence.
DISCUSSION Nerve sheath myxomas are cutaneous neoplasms of peripheral nerve sheath origin, which usually
FIGURE 3. MRI scan of the orbit 15 months after diagnosis. Axial T1-weighted section showing muscle fiber bundles crossing the tumor mass (black arrows).
appear in the extremities. They predominantly affect young adults (their incidence peaks in the fourth decade of life), and affect men and women with nearly equal frequency.1,3 Here, we describe the case of a female patient (older than the reported mean age) with a nerve sheath myxoma involving an extraocular muscle. These tumors present as painless 0.5–2.5 cm masses, usually as solitary lesions, although several cases of multiple lesions have been described. Histologically, nerve sheath myxomas are comprised of distinct lobules separated by fibrous connective tissue. Each lobule consists of a myxoid matrix composed of hyaluronic acid or sulfated acid mucins. Tumor cells are spindle-shaped or stellate. Usually, these cells are scarcely pleomorphic and show few mitotic figures. Immunohistochemical data indicate that these tumors are typically strongly immunoreactive for S-100 protein and glial fibrilary acidic protein.1,4 The treatment of choice is complete tumor excision, ensuring adequate safety margins to minimize the risk of tumor recurrence. In effect, recurrence is rare and is usually linked to inadequate or marginal excision. Tumors also showing a myxoid stroma, such as neurothekeomas, have been often included in the same morphologic spectrum as nerve sheath myxomas. In effect, major works on soft tissue tumors synonymously classify ‘‘classic neurothekeoma’’ and nerve sheath myxoma.5,6 Neurothekeomas and nerve sheath myxomas have been related according to histopathologic similarities and the resemblance of neurothekeomas to non-neoplastic neural structures.
FIGURE 4. PET/CT scan. (A) Axial CT section identifying the intraconal mass in the posterior region of the left orbit (asterisk). (B) PET/CT fusion image revealing no signs of metabolic activity of the orbital mass (asterisk) as a lack of 18F-FDG (Fluoro-DeoxyGlucose) deposition (deposits in the brain indicated). (C) PET image showing no 18F-FDG deposits in the lesion (asterisk). Seminars in Ophthalmology
Orbital Nerve Seath Myxoma 319
FIGURE 5. Histopathology. (A) The tumor consisted of myxoid nodules with sparse cells (hematoxylin-eosin, X100). (B) At higher magnification, spindle and stellate cells of the tumor with no atypia can be seen in a myxoid stroma (hematoxylin-eosin, X400). (C) Tumor cells immunostained with antibodies against CD34 (black arrows) (X200). (D) Tumor cells positive for S100 protein (X400). TABLE 1. Reported immunological findings neurothekeomas and nerve sheath myxomas8. Neurothekeomas Immunohistochemistry S100 SMA Factor XIIIa NSE CD34 EMA NKI-C3
of
Nerve sheath myxomas +
+/ + +
/+ + + +/
+
In addition, some authors have reported a similar immunohistochemical profile for neurothekeomas to that of cultured cells of nerve sheath origin in rats, suggesting that neurothekeomas are composed of immature, undifferentiated nerve sheath cells3. In contrast, recent studies have identified reproducible clinical, histopathologic, immunohistochemical,7,8 and genetic3 differences between the two entities. !
2015 Informa Healthcare USA, Inc.
Thus, cellular neurothekeoma (and classic neurothekeoma with myxoid components) is positive for NKIC3 and negative for GFAP, CD34, and S100 protein, whereas nerve sheath myxoma is positive for GFAP, CD34, and S100 protein, and negative for NKI-C3 (Table 1).7,8 Recent morphological, immunohistochemical, and ultrastructural data reported by Fetsch et al.8 provide strong support for the idea that nerve sheath myxomas are a myxoid variant of schwannoma. In two similar studies, Hornick et al.9 and Fetsch et al.8 confirmed previous suggestions that neurothekeomas are variants of cutaneous fibrohistiocyte tumors, which are benign fibroblast and histiocyte tumors showing a wide range of histomorphologic features.3 According to recent gene expression array data reported by Sheth et al.,3 there is compelling evidence that nerve sheath myxomas are of peripheral nerve sheath origin and as such differ from neurothekeomas. Further, reported data have revealed many similarities in gene expression between neurothekeomas and cellular fibrous histiocytomas, supporting
320 I. Rodrı´guez-Un˜a et al. recent arguments that these entities may, in fact, be related. Many differentially expressed genes in nerve sheath myxomas and neurothekeomas suggest that they are, in fact, unrelated. These data, along with cluster analysis and principal component analysis, have revealed two molecular groups: a nerve sheath myxoma/schwannoma group and a neurothekeoma/ cellular fibrous histiocytoma group. Consequently, based on its histological appearance and on its immunohistochemical features, our case was classified as an orbital nerve sheath myxoma, according to descriptions by Fetsch et al.4
CONCLUSION In conclusion, this is the second case reported in the literature of a nerve sheath myxoma located in the orbit, and possibly the first description of such a tumor involving the extraocular muscles. The case described was inadvertently detected as a painless, slow-growing mass of possible intramuscular origin in the intraconal space. Although rare, this tumor should be considered in the differential diagnosis of orbital masses.1,10 The possibility of infiltration of deeper tissues should also be evaluated. Once diagnosed, the treatment of choice is complete excision, ensuring adequate safety margins to minimize the risk of tumor recurrence.
ACKNOWLEDGEMENTS The contents of this report were presented as a free paper at the XXII ‘‘Sociedad Espan˜ola de Cirugı´a Pla´stica Ocular y Orbitaria’’ (SECPOO) Meeting, June 14-15th 2012, Badajoz, Spain.
DECLARATION OF INTEREST The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
REFERENCES 1. Sa´nchez-Orgaz M, Grabowska A, Arbizu-Duralde A, et al. Orbital nerve sheath myxoma: a case report. Ophthal Plast Reconstr Surg 2011;27:106–108. 2. Składzien´ J, Przeklasa R, Tomik J, Czopek J. Neurothekeoma of the orbit. Otolaryngol Pol 2011;65:54–58. 3. Sheth S, Li X, Binder S, Dry SM. Differential gene expression profiles of neurothekeomas and nerve sheath myxomas by microarray analysis. Mod Pathol 2011;24: 343–354. 4. Fetsch JF, Laskin WB, Miettinen M. Nerve sheath myxoma: a clinicopathologic and immunohistochemical analysis of 57 morphologically distinctive, S-100 protein- and GFAPpositive, myxoid peripheral nerve sheath tumors with a predilection for the extremities and a high local recurrence rate. Am J Surg Pathol 2005;29:1615–1624. 5. Enzinger FM, Weiss SW. Soft Tissue Tumors, 3rd ed.; St. Louis, MO: Mosby, 1995. 6. Folpe AL, Inwards CY. Bone and Soft Tissue Pathology: foundations in Diagnostic Pathology, 1st ed.; Philadelphia: Saunders/Elsevier, 2010. 7. Papalas JA, Proia AD, Hitchcock M, et al. Neurothekeoma palpebrae: a report of 3 cases. Am J Dermatopathol 2010;32: 374–379. 8. Fetsch JF, Laskin WB, Hallman JR, et al. Neurothekeoma: an analysis of 178 tumors with detailed immunohistochemical data and long-term patient follow-up information. Am J Surg Pathol 2007;31:1103–1114. 9. Hornick JL, Fletcher CD. Cellular neurothekeoma: detailed characterization in a series of 133 cases. Am J Surg Pathol 2007;31:329–340. 10. Mathew S, Nandeesh BN, Vasu U, Michael SG. Neurothekeoma of the eyelid: a case report. Indian J Ophthalmol 2008;56:334–336.
Seminars in Ophthalmology
Copyright of Seminars in Ophthalmology is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
C ASE REPORT
Orbital Nerve Seath Myxoma with Extraocular Muscle Involvement: A Rare Case Ignacio Rodrı´guez-Un˜a1, Juan A. Troyano-Rivas1, Cristina Gonza´lez-Garcı´a1, Reinaldo Chı´charo-de-Freitas2, Juan J. Ortiz-Zapata3, Luis Ortega-Medina3, Nicola´s Toledano-Ferna´ndez4, and Julia´n Garcı´a-Feijoo1,5 1
Department of Ophthalmology, Hospital Clı´nico San Carlos, Instituto de Investigacio´n Sanitaria del Hospital Clı´nico San Carlos (IdISSC), Madrid, Spain, 2Department of Nuclear Medicine, Hospital Clı´nico San Carlos, Madrid, Spain, 3Department of Anatomic Pathology, Hospital Clı´nico San Carlos, Madrid, Spain, 4Department of Ophthalmology, Hospital Universitario de Fuenlabrada, Fuenlabrada, Spain, and 5Cooperative Research Network on Age-Related Ocular Pathology, Visual and Life Quality, Instituto de Salud Carlos III, Madrid, Spain
ABSTRACT A 66-year-old woman with breast cancer presented with a painless mass in the left orbit. MRI revealed a welldefined intraconal mass in the temporal quadrant of the orbit. Fifteen months later, a further MRI indicated the mass had grown, displacing the left optic nerve and making contact with the lateral rectus muscle, suggesting its possible intramuscular origin. Despite the clinical and radiological characteristics of the lesion and its slow growth, a PET/CT study was developed because of the history of malignant disease. No metabolic activity of the mass or malignant lesion in other locations was observed. After surgical excision, histopathological examination revealed an abundant myxoid matrix with few spindle-shaped cells and no signs of malignancy. The cells were immunopositive for CD34, positive for S-100 protein, and negative for EMA, actin, and CD57. A diagnosis was made of a nerve sheath myxoma. The orbital location of these tumors is extremely rare. Keywords: Benign tumors, immunohistochemistry, nerve sheath myxoma, neurothekeoma, orbital neoplasms
INTRODUCTION
of Madrid, Spain. Care of the patient in this study was in accordance with the Declaration of Helsinki.
Nerve sheath myxoma is an infrequent benign tumor whose origin and classification remain unclear. Although the appearance of a nerve sheath myxoma in the upper limbs and feet is well documented, this tumor is rarely seen in ophthalmologic practice. To date, there is one reported case in the literature of a nerve sheath myxoma involving the orbit1 and a further case of a similar tumor, a neurothekeoma,2 also affecting the orbit. Here, we describe the case of a female patient with a nerve sheath myxoma arising in the orbit and affecting extraocular muscles. To the best of our knowledge, this is the first report of such a tumor affecting this structure. This study was conducted with the approval of the Ethics Committee of the Hospital Clı´nico San Carlos
CASE REPORT A 66-year-old woman was referred to our ophthalmology department because of a painless mass in the left orbit that had been inadvertently detected in a CT scan of the paranasal sinuses. Her medical history included a recent mastectomy and lymph node removal for breast cancer. The CT revealed an intraconal lesion that made tight contact with the lateral rectus (LR) muscle. Our initial radiologic suspicion was a cavernous hemangioma in the orbit because of the frequency of this tumor and its location.
Received 12 June 2013; accepted 8 December 2013; published online 29 January 2014 Correspondence: Ignacio Rodrı´guez-Un˜a, M.D., Department of Ophthalmology, Hospital Clı´nico San Carlos, Avda. Prof. Martin Lagos S/N, 28040 Madrid, Spain. E-mail: [email protected]
316
Orbital Nerve Seath Myxoma 317
FIGURE 1. MRI scan of the orbit at the time of diagnosis showing axial (A) and coronal sections (B, C). (A) Axial T2-weighted MRI image reveals a strongly enhanced intraconal mass in the left orbit, near the optic nerve. (B) Coronal T2-weighted MRI section showing the relationship between the lesion and lateral rectus muscle. Note the imprint of the mass towards the orbital cone interior. (C) In T1-weighted MRI images, the lesion appears as isointense with the muscle.
FIGURE 2. MRI scan of the orbit 15 months after diagnosis. Axial (A) and coronal sections (B, C) reveal the notable size increase of the tumor mass. (A) Axial T2- weighted MRI image shows the mass medially displacing the optic nerve. (B) Coronal T2-weighted MRI and (C) coronal T1-weighted sections in which the mass appears in close contact with the lateral rectus muscle, causing it to bulge and inferomedially displacing the left optic nerve.
Cranial MRI (magnetic resonance imaging) revealed a homogenous well-defined intraconal mass, 1.10 1.15 1.64 cm, in the left orbit (Figure 1). No exophthalmos, ptosis, or ocular motility limitations were noted. Visual acuity in the left eye was 20/60. The rest of the ophthalmologic examination was normal, including a fundus exam and intraocular pressure. A follow-up MRI three months later indicated a similar situation, although in a further MRI at 12 months (Figure 2A), it was observed that the mass had grown (to 1.50 2.18 1.64 cm), displacing the left optic nerve and contacting tightly with the LR muscle, suggesting its intramuscular location (Figures 2B, C), even with muscle fiber bundles crossing the tumor mass (Figure 3). The patient reported no symptoms. At this point, despite the clinical and radiological characteristics of the lesion and its slow growth, we !
2015 Informa Healthcare USA, Inc.
considered the possibility of metastasis from the patient’s breast tumor and undertook a whole-body PET/CT scan (Figure 4). The scan indicated no metabolic activity of the orbital mass and no malignant lesions at other sites. On these grounds and despite the apparent benignity of the lesion, the decision was made with the patient to excise the mass so that a malignancy could be histologically ruled out. We conducted an orbitotomy without osteotomy through a superior eyelid crease incision. The tumor was completely removed and submitted for histopathological examination. The surgical specimen was a white and soft round mass with a maximum diameter of 2.0 cm. This mass was composed of myxoid nodules with sparse cells. These cells were spindle-shaped or stellate admixed with an abundant myxoid matrix; no atypia were observed (Figures 5A, B). Immunohistochemistry revealed that
318 I. Rodrı´guez-Un˜a et al. the cells were positive for CD34 (Figure 5C), positive for S100 protein (Figure 5D), and negative for EMA, actin, and CD57. These findings led to a diagnosis of orbital nerve sheath myxoma. In the one-month follow-up session, the patient was well with no signs of local recurrence.
DISCUSSION Nerve sheath myxomas are cutaneous neoplasms of peripheral nerve sheath origin, which usually
FIGURE 3. MRI scan of the orbit 15 months after diagnosis. Axial T1-weighted section showing muscle fiber bundles crossing the tumor mass (black arrows).
appear in the extremities. They predominantly affect young adults (their incidence peaks in the fourth decade of life), and affect men and women with nearly equal frequency.1,3 Here, we describe the case of a female patient (older than the reported mean age) with a nerve sheath myxoma involving an extraocular muscle. These tumors present as painless 0.5–2.5 cm masses, usually as solitary lesions, although several cases of multiple lesions have been described. Histologically, nerve sheath myxomas are comprised of distinct lobules separated by fibrous connective tissue. Each lobule consists of a myxoid matrix composed of hyaluronic acid or sulfated acid mucins. Tumor cells are spindle-shaped or stellate. Usually, these cells are scarcely pleomorphic and show few mitotic figures. Immunohistochemical data indicate that these tumors are typically strongly immunoreactive for S-100 protein and glial fibrilary acidic protein.1,4 The treatment of choice is complete tumor excision, ensuring adequate safety margins to minimize the risk of tumor recurrence. In effect, recurrence is rare and is usually linked to inadequate or marginal excision. Tumors also showing a myxoid stroma, such as neurothekeomas, have been often included in the same morphologic spectrum as nerve sheath myxomas. In effect, major works on soft tissue tumors synonymously classify ‘‘classic neurothekeoma’’ and nerve sheath myxoma.5,6 Neurothekeomas and nerve sheath myxomas have been related according to histopathologic similarities and the resemblance of neurothekeomas to non-neoplastic neural structures.
FIGURE 4. PET/CT scan. (A) Axial CT section identifying the intraconal mass in the posterior region of the left orbit (asterisk). (B) PET/CT fusion image revealing no signs of metabolic activity of the orbital mass (asterisk) as a lack of 18F-FDG (Fluoro-DeoxyGlucose) deposition (deposits in the brain indicated). (C) PET image showing no 18F-FDG deposits in the lesion (asterisk). Seminars in Ophthalmology
Orbital Nerve Seath Myxoma 319
FIGURE 5. Histopathology. (A) The tumor consisted of myxoid nodules with sparse cells (hematoxylin-eosin, X100). (B) At higher magnification, spindle and stellate cells of the tumor with no atypia can be seen in a myxoid stroma (hematoxylin-eosin, X400). (C) Tumor cells immunostained with antibodies against CD34 (black arrows) (X200). (D) Tumor cells positive for S100 protein (X400). TABLE 1. Reported immunological findings neurothekeomas and nerve sheath myxomas8. Neurothekeomas Immunohistochemistry S100 SMA Factor XIIIa NSE CD34 EMA NKI-C3
of
Nerve sheath myxomas +
+/ + +
/+ + + +/
+
In addition, some authors have reported a similar immunohistochemical profile for neurothekeomas to that of cultured cells of nerve sheath origin in rats, suggesting that neurothekeomas are composed of immature, undifferentiated nerve sheath cells3. In contrast, recent studies have identified reproducible clinical, histopathologic, immunohistochemical,7,8 and genetic3 differences between the two entities. !
2015 Informa Healthcare USA, Inc.
Thus, cellular neurothekeoma (and classic neurothekeoma with myxoid components) is positive for NKIC3 and negative for GFAP, CD34, and S100 protein, whereas nerve sheath myxoma is positive for GFAP, CD34, and S100 protein, and negative for NKI-C3 (Table 1).7,8 Recent morphological, immunohistochemical, and ultrastructural data reported by Fetsch et al.8 provide strong support for the idea that nerve sheath myxomas are a myxoid variant of schwannoma. In two similar studies, Hornick et al.9 and Fetsch et al.8 confirmed previous suggestions that neurothekeomas are variants of cutaneous fibrohistiocyte tumors, which are benign fibroblast and histiocyte tumors showing a wide range of histomorphologic features.3 According to recent gene expression array data reported by Sheth et al.,3 there is compelling evidence that nerve sheath myxomas are of peripheral nerve sheath origin and as such differ from neurothekeomas. Further, reported data have revealed many similarities in gene expression between neurothekeomas and cellular fibrous histiocytomas, supporting
320 I. Rodrı´guez-Un˜a et al. recent arguments that these entities may, in fact, be related. Many differentially expressed genes in nerve sheath myxomas and neurothekeomas suggest that they are, in fact, unrelated. These data, along with cluster analysis and principal component analysis, have revealed two molecular groups: a nerve sheath myxoma/schwannoma group and a neurothekeoma/ cellular fibrous histiocytoma group. Consequently, based on its histological appearance and on its immunohistochemical features, our case was classified as an orbital nerve sheath myxoma, according to descriptions by Fetsch et al.4
CONCLUSION In conclusion, this is the second case reported in the literature of a nerve sheath myxoma located in the orbit, and possibly the first description of such a tumor involving the extraocular muscles. The case described was inadvertently detected as a painless, slow-growing mass of possible intramuscular origin in the intraconal space. Although rare, this tumor should be considered in the differential diagnosis of orbital masses.1,10 The possibility of infiltration of deeper tissues should also be evaluated. Once diagnosed, the treatment of choice is complete excision, ensuring adequate safety margins to minimize the risk of tumor recurrence.
ACKNOWLEDGEMENTS The contents of this report were presented as a free paper at the XXII ‘‘Sociedad Espan˜ola de Cirugı´a Pla´stica Ocular y Orbitaria’’ (SECPOO) Meeting, June 14-15th 2012, Badajoz, Spain.
DECLARATION OF INTEREST The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
REFERENCES 1. Sa´nchez-Orgaz M, Grabowska A, Arbizu-Duralde A, et al. Orbital nerve sheath myxoma: a case report. Ophthal Plast Reconstr Surg 2011;27:106–108. 2. Składzien´ J, Przeklasa R, Tomik J, Czopek J. Neurothekeoma of the orbit. Otolaryngol Pol 2011;65:54–58. 3. Sheth S, Li X, Binder S, Dry SM. Differential gene expression profiles of neurothekeomas and nerve sheath myxomas by microarray analysis. Mod Pathol 2011;24: 343–354. 4. Fetsch JF, Laskin WB, Miettinen M. Nerve sheath myxoma: a clinicopathologic and immunohistochemical analysis of 57 morphologically distinctive, S-100 protein- and GFAPpositive, myxoid peripheral nerve sheath tumors with a predilection for the extremities and a high local recurrence rate. Am J Surg Pathol 2005;29:1615–1624. 5. Enzinger FM, Weiss SW. Soft Tissue Tumors, 3rd ed.; St. Louis, MO: Mosby, 1995. 6. Folpe AL, Inwards CY. Bone and Soft Tissue Pathology: foundations in Diagnostic Pathology, 1st ed.; Philadelphia: Saunders/Elsevier, 2010. 7. Papalas JA, Proia AD, Hitchcock M, et al. Neurothekeoma palpebrae: a report of 3 cases. Am J Dermatopathol 2010;32: 374–379. 8. Fetsch JF, Laskin WB, Hallman JR, et al. Neurothekeoma: an analysis of 178 tumors with detailed immunohistochemical data and long-term patient follow-up information. Am J Surg Pathol 2007;31:1103–1114. 9. Hornick JL, Fletcher CD. Cellular neurothekeoma: detailed characterization in a series of 133 cases. Am J Surg Pathol 2007;31:329–340. 10. Mathew S, Nandeesh BN, Vasu U, Michael SG. Neurothekeoma of the eyelid: a case report. Indian J Ophthalmol 2008;56:334–336.
Seminars in Ophthalmology
Copyright of Seminars in Ophthalmology is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
