The Journal of Foot & Ankle Surgery 53 (2014) 335–339
Contents lists available at ScienceDirect
The Journal of Foot & Ankle Surgery journal homepage: www.jfas.org
Giant Schwannoma of the First Metatarsal: A Rare Entity Mohammed Tahir Ansari, MS, MRCS 1, Shishir Rastogi, MS 2, Shah Alam Khan, MS, FRCS, MCh 3, Chandershekhar Yadav, MS 3, Laxman Rijal, MS 4 1
Assistant Professor of Orthopaedics, Department of Emergency Medicine, All India Institute of Medical Sciences, New Delhi, India Professor, Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, India 3 Additional Professor, Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, India 4 Orthopaedic Surgeon, Department of Orthopaedics, Civil Service Hospital, Kathmandu, Nepal 2
a r t i c l e i n f o
a b s t r a c t
Level of Clinical Evidence: 4
Schwannomas of osseous origin are rare, and schwannomas of the short tubular bones are even rarer. These benign-looking tumors are difficult to diagnose using imaging alone. However, histopathologic evaluation of a biopsy specimen can establish the diagnosis by identifying Antoni type A and B zones. Curettage and bone grafting will probably be adequate for treatment because malignant changes are unlikely. Large lesions can require en bloc excision and reconstruction. We describe what appears to be only the second case of a schwannoma in the first metatarsal of the foot in a 48-year-old woman. The lesion was poorly contained, with obvious breaks in the cortical shell. The diagnosis was confirmed by pathologic analysis. The lesion was successfully treated with en bloc resection and reconstruction with a nonvascularized fibular graft. Ó 2014 by the American College of Foot and Ankle Surgeons. All rights reserved.
Keywords: bone fibula nerve sheath neurilemmoma Schwann cell tumor
Schwannoma, also known as a neurilemmoma, is a benign tumor arising from the sheath of myelinated nerve fibers that can occur anywhere in the body (1). Most osseous Schwannomas occur in the facial bones, mandible, maxilla, nasal bone, or facial sinuses (2). Few cases of this nerve sheath tumor have been reported in the long bones (3–11). Even more rare have been those involving the short tubular bones (12). We have described a Schwannoma of the first metatarsal that had eroded the entire first metatarsal by the time of presentation.
ankle to the first metatarsophalangeal joint. The mass was hard and moderately tender, and the underlying skin was not adherent to the
Case Report A 48-year-old female presented to our hospital and reported a 9-year history of swelling in her right foot. The swelling had been small in the beginning but had gradually increased over the years. Our female patient lived in a rural area and did not seek medical attention until the swelling had suddenly increased in size and a dull aching pain had developed over the dorsum of the foot about 1 year before presentation. The swollen area was 7 6 cm and had spread over the dorsomedial aspect of the foot, extending from 3 cm distal to the
Financial Disclosure: None reported. Conflict of Interest: None reported. Address correspondence to: Mohammed Tahir Ansari, MS, MRCS, Assistant Professor, Department of Emergency Medicine, All India Institute of Medical Sciences, New Delhi, India. E-mail address: [email protected] (M.T. Ansari).
Fig. 1. Anteroposterior and oblique radiographic views of the foot showing an expansile, osteolytic benign lesion involving the first metatarsal.
1067-2516/$ - see front matter Ó 2014 by the American College of Foot and Ankle Surgeons. All rights reserved. http://dx.doi.org/10.1053/j.jfas.2014.01.014
336
M.T. Ansari et al. / The Journal of Foot & Ankle Surgery 53 (2014) 335–339
Fig. 2. T1- and T2-weighted axial magnetic resonance images of the foot showing the lesion.
tumor. The local temperature was normal. She reported no other similar lumps or tumors elsewhere. A biplane radiograph of the right foot showed a well-delineated, expansile, lytic, globular, and trabeculated lesion (Fig. 1). An expansile and heterogeneous isointense lesion involving the first metatarsal was apparent on T1-weighted magnetic resonance imaging (MRI). The
lesion appeared to be heterogeneous and hyperintense on T2weighted MRI scans, with little break in the dorsal cortex (Figs. 2 and 3). Histopathologic examination of a core biopsy specimen revealed some areas of fusiform cells, with elongated, ovoid nuclei in the form of a palisade that gave off an interstitial substance to form the Verocay bodies (Antoni type A zones) and other areas of irregular cells with a
Fig. 3. T1- and T2-weighted sagittal magnetic resonance images of the foot showing the lesion.
M.T. Ansari et al. / The Journal of Foot & Ankle Surgery 53 (2014) 335–339
337
Fig. 4. Hypercellular areas indicating an Antoni A area, hypocellular areas indicating an Antoni B area, and Verocay bodies are seen under the microscope at 40 magnification.
myxoid matrix and a looser appearance (Antoni type B zones), which suggested schwannoma (Fig. 4). The tumor was excised and reconstructed in the operating room using a graft from the ipsilateral fibula and stabilized with two 2-mm Kirschner wires (Fig. 5). The abductor hallucis was transferred to increase vascularity and to provide soft tissue coverage over the fibula. After 4 months, radiographs showed that the fibular graft had become incorporated; the joint was mobilized, with gradual resumption of weightbearing ambulation (Fig. 6). The clinical and radiologic follow-up examinations 2 years later found no features suggestive of recurrence or nonunion. Discussion
Fig. 6. Anteroposterior, lateral, and oblique radiographic views of the foot showing a well-incorporated fibula at the fourth postoperative month.
Schwannomas or neurilemmomas arise from the Schwann cells. Comprising 1% to 10% of all soft tissue tumors, they are the least common benign tumors of the peripheral nerve sheath. Most have been solitary tumors, but multiple neurilemmomas occurring in association with neurofibromatosis type II have been reported (13). Intraosseous schwannomas account for less than 1% of all benign bone tumors (14). The most frequent locations have been the facial bones, cranium, and sacrum (15). Its rarity has been attributed to the paucity of sensory nerve fibers in bone (16). The tumor can be intramedullary or located in the nutrient canal (17). When presenting in the appendicular skeleton, most will arise from the long bones of the lower leg
and forearm. We found only 1 other report of a schwannoma arising from the first metatarsal (12). Interosseous schwannomas are usually less than 5 cm in diameter. Those larger than 5 cm, such as the case we have described, are termed giant schwannomas (18). Rarely, they can turn malignant if associated with neurofibromatosis (19,20). They will usually be asymptomatic, slow-growing tumors. In our case, the neurilemmoma had been growing for at least 9 years. The appearance on MRI will usually be characteristic of soft tissue lesions, which will be isointense or hypointense on T1-weighted images and hyperintense with a heterogeneous appearance on T2-
Fig. 5. Intraoperative photograph showing reconstruction of the first metatarsal with a fibular graft.
Fig. 7. View of a branch of the deep peroneal nerve entering the first metatarsal. Most of the lesions will arise from the nerve entering through the nutrient canal of the bone.
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M.T. Ansari et al. / The Journal of Foot & Ankle Surgery 53 (2014) 335–339
and reconstruction with a bone graft (Fig. 8) (11). We performed en bloc resection in our patient because several cortical breeches were evident. The recurrences reported in early published studies have been attributed to incomplete tumor excision (13). We reconstructed the medial arch of foot with a graft from the fibula that was fixed with two 2-mm Kirschner wires. We then transposed a bipedicular abductor hallucis flap over the fibula to provide muscle coverage to the nonvascularized bone. A distally based, abductor hallucis muscle flap has been described for covering forefoot defects and was chosen to provide coverage to the fibula and increase the vascularity (30). Vascularized osteocutaneous fibular free flaps have been used to reconstruct the foot but require technical expertise and longer operative times (31). With the available surgical team and our learning curve, we preferred using the nonvascularized fibula graft in the present case. In conclusion, the case we have described in our patient appears to be only the second case of a schwannoma localized in the first metatarsal. The lesion was continuous with the dorsal branch of the deep peroneal nerve and had progressed until it had completely destroyed the first metatarsal. Although very rare, an intraosseous schwannoma should be included in the differential diagnosis of painful, radiologically benign-appearing, expansile lesions arising from the bone. References
Fig. 8. Anteroposterior and lateral radiograph of the donor site showing the large gap after harvest of the fibular graft.
weighted images (21). A “string sign” for schwannoma has been described as the attenuated margins above and below the lesion on MRI (22). Schwannomas as primary lesions of bone usually appear as benign cystic lesions. Radiologically, they will appear as welldemarcated, lytic lesions with sclerosis of the borders and trabeculations in the interior that can occasionally break into the cortex (23–25). In some cases, differentiating interosseous calcification from tumors of cartilaginous origin can be difficult (26). The differential diagnosis includes simple bone cyst, aneurysmal bone cyst, nonossifying fibroma, benign fibrous histiocytoma, desmoplastic fibroma, fibrous dysplasia, chondromyxoid fibroma, enchondroma, giant cell tumor of the tendon sheath, and plasmacytoma. Intraosseous neurilemmomas typically arise in association with a nerve that enters the bone through a nutrient canal (Fig. 7) (27). Just as in the present case, the tumor can also arise from a branch of the deep peroneal nerve and traverse to the nutrient canal of the first metatarsal. Histopathologic examination can help to establish the correct diagnosis. These tumors are composed of benign-appearing spindle cells that will be broadly distributed in 2 zones: the Antoni A zone, with spindle cells in a palisade formation surrounded by an interstitial substance that forms the Verocay bodies; and the Antoni B zone, which has irregular cells and a myxoid component (16). Both zones of cellularity have often been found in the same tumor (18). Although most lesions will contain both components, a predominance of Antoni B type tissue has been thought by some investigators to indicate aggressiveness along the spectrum from a neurilemmoma to a malignant tumor of the peripheral nerve sheath (28,29). In uncertain cases, immunochemical staining for S100 protein will be extremely valuable, because schwannomas will be diffusely positive for this marker (13). Curettage and bone grafting are probably adequate treatment for intraosseous schwannomas, because malignant changes have been rare (3,7,23). However, large lesions might require en bloc excision
1. Woodruff JM, Kourea HP, Louis DR, Scheithauer BW. Schwannoma. In: World Health Organization Classification of Tumors: Pathology and Genetics of Tumors of the Nervous System, pp. 164–166, edited by P Kleihues, WK Cavenee, IARC Press, Lyon, France, 2000. 2. Chi AC, Carey J, Muller S. Intraosseous schwannoma of the mandible: a case report and review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 96:54–65, 2003. 3. Mutema GK, Sorger J. Intraosseous schwannoma of the humerus. Skeletal Radiol 31:419–421, 2002. J, Calmet J, Sirvent JJ, Dome nech S. Intraosseous neurilemmoma of the radius: 4. Gine a case report. J Hand Surg Am 25:365–369, 2000. 5. Gordon EJ. Solitary intraosseous neurilemmoma of the tibia: review of intraosseous neurilemmoma and neurofibroma. Clin Orthop Relat Res 117:271–782, 1976. 6. Jain VK, Jain D, Kumar S. Proximal tibial epiphyseal intraosseous schwannoma a rare entity. J Pediatr Orthop 30:411, 2010. 7. Aoki J, Tanikawa H, Fujioka F, Ishii K, Seo GS, Karakida O, Sone S. Intraosseous neurilemmoma of the fibula. Skeletal Radiol 26:60–63, 1997. 8. Chevalier X, Montazel JL, Voisin MC, Hernigou P. Intraosseous neurilemmoma of the lower third of the fibula. AJR Am J Roentgenol 165:1555–1556, 1995. 9. Kim M-J, Choi J, Khang S-K, Kim J-S, Lee J-S, Cho K-J. Primary intraosseous melanotic schwannoma of the fibula associated with the Carney complex. Pathol Int 56:538–542, 2006. 10. Luk’ianchenko AB, Petrovichev NN, Ol’khovskaia IG. Neurilemmoma of the fibula (a case report). Vopr Onkol 30:91–93, 1984 [in Russian]. 11. Palocaren T, Walter NM, Madhuri V, Gibikote S. Schwannoma of the fibula. J Bone Joint Surg Br 90:803–805, 2008. 12. Sufian Z, Mazhar A, Lateef JZ, Rana SK. Intraosseous schwannoma of head of first metatarsal: a rare entity. Indian J Pathol Microbiol 52:286–288, 2009. 13. Randall R. Tumors in orthopedics. In: Current Diagnosis & Treatment in Orthopedicsed 3, Lange Medical Books/McGraw-Hill, New York, 2003, pp. 286–369. 14. World Health Organization Classification of Tumors: Pathology and Genetics: Tumors of Soft Tissue and Bone, edited by CDM Fletcher, KK Umni, F Mertens, IARC Press, Lyon, France, 2002. 15. Sadeghi EM, Koenig LJ, Clark D. Intrabony neurilemmoma: diagnosis and management. J Am Dent Assoc 129:729–732, 1998. 16. Monte SM, Dorfman HD, Chandra R, Malawer M. Intraosseous schwannoma: histologic features, ultrastructure, and review of the literature. Hum Pathol 15:551–558, 1984. 17. Samter TG, Vellios F, Shafer WG. Neurilemmoma of bone: report of 3 cases with a review of the literature. Radiology 75:215–222, 1960. 18. Ritt MJ, Bos KE. A very large neurilemmoma of the anterior interosseous nerve. J Hand Surg Br 16:98–100, 1991. 19. Grossman MR, Mandracchia VJ, Urbas WM, Mandracchia DM. Neurilemmoma of the posterior tibial nerve with an uncommon case presentation. J Foot Surg 31:219–224, 1992. 20. Wood MK, Erdmann MW, Davies DM. Malignant schwannoma mistakenly diagnosed as carpal tunnel syndrome. J Hand Surg Br 18:187–188, 1993. 21. Dunnick NR. Image interpretation session: 1999. Intraosseous malignant peripheral nerve sheath tumor (malignant schwannoma) in a patient with neurofibromatosis. Radiographics 20:271–273, 2000.
M.T. Ansari et al. / The Journal of Foot & Ankle Surgery 53 (2014) 335–339
22. Maini A, Tripathi M, Shekar NC, Malhotra A. Sciatic schwannoma of the thigh detected on bone scan: a case report. Clin Imaging 27:191–193, 2003. 23. Pyati PS, Sanzone AG. Intraosseous neurilemmoma of the calcaneus. Orthopedics 19:353–355, 1996. 24. Sanado L, Ruiz JL, Laidler L, Polo M. Femoral intraosseous neurilemmoma. Arch Orthop Trauma Surg 110:212–213, 1991. 25. Trinez G, Rozan R, Petit P, Donne Y, Delmaire M. Osseous schwannoma of the tibia. J Radiol Electrol Med Nucl 50(suppl 5):407, 1969. 26. Schultz E, Sapan MR, McHeffey-Atkinson B, Naidich JB, Arlen M. Case report 872: ‘ancient’ schwannoma (degenerated neurilemmoma). Skeletal Radiol 23:593–595, 1994.
339
27. Sherman M. The nerves of bone. J Bone Joint Surg Am 45:522–528, 1963. 28. Jacobs RL, Fox TA. Neurilemmoma of bone: a case report with a review of the literature. Clin Orthop Relat Res 87:248–253, 1972. 29. Wesche WA, Khare V, Rao BN, Bowman LC, Parham DM. Malignant peripheral nerve sheath tumor of bone in children and adolescents. Pediatr Dev Pathol 2:159–167,1999. 30. Schwabegger AH, Shafighi M, Harpf C, Gardetto A, Gurunluoglu R. Distally based abductor hallucis muscle flap: anatomic basis and clinical application. Ann Plast Surg 51:505–508, 2003. 31. Chung YK, Hong JP, Kang SY, Kim SW, Tark KC. A vascularized osteocutaneous fibular free flap for reconstruction of a complex injury of the foot. Ann Plast Surg 45:541–543, 2000.
Contents lists available at ScienceDirect
The Journal of Foot & Ankle Surgery journal homepage: www.jfas.org
Giant Schwannoma of the First Metatarsal: A Rare Entity Mohammed Tahir Ansari, MS, MRCS 1, Shishir Rastogi, MS 2, Shah Alam Khan, MS, FRCS, MCh 3, Chandershekhar Yadav, MS 3, Laxman Rijal, MS 4 1
Assistant Professor of Orthopaedics, Department of Emergency Medicine, All India Institute of Medical Sciences, New Delhi, India Professor, Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, India 3 Additional Professor, Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, India 4 Orthopaedic Surgeon, Department of Orthopaedics, Civil Service Hospital, Kathmandu, Nepal 2
a r t i c l e i n f o
a b s t r a c t
Level of Clinical Evidence: 4
Schwannomas of osseous origin are rare, and schwannomas of the short tubular bones are even rarer. These benign-looking tumors are difficult to diagnose using imaging alone. However, histopathologic evaluation of a biopsy specimen can establish the diagnosis by identifying Antoni type A and B zones. Curettage and bone grafting will probably be adequate for treatment because malignant changes are unlikely. Large lesions can require en bloc excision and reconstruction. We describe what appears to be only the second case of a schwannoma in the first metatarsal of the foot in a 48-year-old woman. The lesion was poorly contained, with obvious breaks in the cortical shell. The diagnosis was confirmed by pathologic analysis. The lesion was successfully treated with en bloc resection and reconstruction with a nonvascularized fibular graft. Ó 2014 by the American College of Foot and Ankle Surgeons. All rights reserved.
Keywords: bone fibula nerve sheath neurilemmoma Schwann cell tumor
Schwannoma, also known as a neurilemmoma, is a benign tumor arising from the sheath of myelinated nerve fibers that can occur anywhere in the body (1). Most osseous Schwannomas occur in the facial bones, mandible, maxilla, nasal bone, or facial sinuses (2). Few cases of this nerve sheath tumor have been reported in the long bones (3–11). Even more rare have been those involving the short tubular bones (12). We have described a Schwannoma of the first metatarsal that had eroded the entire first metatarsal by the time of presentation.
ankle to the first metatarsophalangeal joint. The mass was hard and moderately tender, and the underlying skin was not adherent to the
Case Report A 48-year-old female presented to our hospital and reported a 9-year history of swelling in her right foot. The swelling had been small in the beginning but had gradually increased over the years. Our female patient lived in a rural area and did not seek medical attention until the swelling had suddenly increased in size and a dull aching pain had developed over the dorsum of the foot about 1 year before presentation. The swollen area was 7 6 cm and had spread over the dorsomedial aspect of the foot, extending from 3 cm distal to the
Financial Disclosure: None reported. Conflict of Interest: None reported. Address correspondence to: Mohammed Tahir Ansari, MS, MRCS, Assistant Professor, Department of Emergency Medicine, All India Institute of Medical Sciences, New Delhi, India. E-mail address: [email protected] (M.T. Ansari).
Fig. 1. Anteroposterior and oblique radiographic views of the foot showing an expansile, osteolytic benign lesion involving the first metatarsal.
1067-2516/$ - see front matter Ó 2014 by the American College of Foot and Ankle Surgeons. All rights reserved. http://dx.doi.org/10.1053/j.jfas.2014.01.014
336
M.T. Ansari et al. / The Journal of Foot & Ankle Surgery 53 (2014) 335–339
Fig. 2. T1- and T2-weighted axial magnetic resonance images of the foot showing the lesion.
tumor. The local temperature was normal. She reported no other similar lumps or tumors elsewhere. A biplane radiograph of the right foot showed a well-delineated, expansile, lytic, globular, and trabeculated lesion (Fig. 1). An expansile and heterogeneous isointense lesion involving the first metatarsal was apparent on T1-weighted magnetic resonance imaging (MRI). The
lesion appeared to be heterogeneous and hyperintense on T2weighted MRI scans, with little break in the dorsal cortex (Figs. 2 and 3). Histopathologic examination of a core biopsy specimen revealed some areas of fusiform cells, with elongated, ovoid nuclei in the form of a palisade that gave off an interstitial substance to form the Verocay bodies (Antoni type A zones) and other areas of irregular cells with a
Fig. 3. T1- and T2-weighted sagittal magnetic resonance images of the foot showing the lesion.
M.T. Ansari et al. / The Journal of Foot & Ankle Surgery 53 (2014) 335–339
337
Fig. 4. Hypercellular areas indicating an Antoni A area, hypocellular areas indicating an Antoni B area, and Verocay bodies are seen under the microscope at 40 magnification.
myxoid matrix and a looser appearance (Antoni type B zones), which suggested schwannoma (Fig. 4). The tumor was excised and reconstructed in the operating room using a graft from the ipsilateral fibula and stabilized with two 2-mm Kirschner wires (Fig. 5). The abductor hallucis was transferred to increase vascularity and to provide soft tissue coverage over the fibula. After 4 months, radiographs showed that the fibular graft had become incorporated; the joint was mobilized, with gradual resumption of weightbearing ambulation (Fig. 6). The clinical and radiologic follow-up examinations 2 years later found no features suggestive of recurrence or nonunion. Discussion
Fig. 6. Anteroposterior, lateral, and oblique radiographic views of the foot showing a well-incorporated fibula at the fourth postoperative month.
Schwannomas or neurilemmomas arise from the Schwann cells. Comprising 1% to 10% of all soft tissue tumors, they are the least common benign tumors of the peripheral nerve sheath. Most have been solitary tumors, but multiple neurilemmomas occurring in association with neurofibromatosis type II have been reported (13). Intraosseous schwannomas account for less than 1% of all benign bone tumors (14). The most frequent locations have been the facial bones, cranium, and sacrum (15). Its rarity has been attributed to the paucity of sensory nerve fibers in bone (16). The tumor can be intramedullary or located in the nutrient canal (17). When presenting in the appendicular skeleton, most will arise from the long bones of the lower leg
and forearm. We found only 1 other report of a schwannoma arising from the first metatarsal (12). Interosseous schwannomas are usually less than 5 cm in diameter. Those larger than 5 cm, such as the case we have described, are termed giant schwannomas (18). Rarely, they can turn malignant if associated with neurofibromatosis (19,20). They will usually be asymptomatic, slow-growing tumors. In our case, the neurilemmoma had been growing for at least 9 years. The appearance on MRI will usually be characteristic of soft tissue lesions, which will be isointense or hypointense on T1-weighted images and hyperintense with a heterogeneous appearance on T2-
Fig. 5. Intraoperative photograph showing reconstruction of the first metatarsal with a fibular graft.
Fig. 7. View of a branch of the deep peroneal nerve entering the first metatarsal. Most of the lesions will arise from the nerve entering through the nutrient canal of the bone.
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M.T. Ansari et al. / The Journal of Foot & Ankle Surgery 53 (2014) 335–339
and reconstruction with a bone graft (Fig. 8) (11). We performed en bloc resection in our patient because several cortical breeches were evident. The recurrences reported in early published studies have been attributed to incomplete tumor excision (13). We reconstructed the medial arch of foot with a graft from the fibula that was fixed with two 2-mm Kirschner wires. We then transposed a bipedicular abductor hallucis flap over the fibula to provide muscle coverage to the nonvascularized bone. A distally based, abductor hallucis muscle flap has been described for covering forefoot defects and was chosen to provide coverage to the fibula and increase the vascularity (30). Vascularized osteocutaneous fibular free flaps have been used to reconstruct the foot but require technical expertise and longer operative times (31). With the available surgical team and our learning curve, we preferred using the nonvascularized fibula graft in the present case. In conclusion, the case we have described in our patient appears to be only the second case of a schwannoma localized in the first metatarsal. The lesion was continuous with the dorsal branch of the deep peroneal nerve and had progressed until it had completely destroyed the first metatarsal. Although very rare, an intraosseous schwannoma should be included in the differential diagnosis of painful, radiologically benign-appearing, expansile lesions arising from the bone. References
Fig. 8. Anteroposterior and lateral radiograph of the donor site showing the large gap after harvest of the fibular graft.
weighted images (21). A “string sign” for schwannoma has been described as the attenuated margins above and below the lesion on MRI (22). Schwannomas as primary lesions of bone usually appear as benign cystic lesions. Radiologically, they will appear as welldemarcated, lytic lesions with sclerosis of the borders and trabeculations in the interior that can occasionally break into the cortex (23–25). In some cases, differentiating interosseous calcification from tumors of cartilaginous origin can be difficult (26). The differential diagnosis includes simple bone cyst, aneurysmal bone cyst, nonossifying fibroma, benign fibrous histiocytoma, desmoplastic fibroma, fibrous dysplasia, chondromyxoid fibroma, enchondroma, giant cell tumor of the tendon sheath, and plasmacytoma. Intraosseous neurilemmomas typically arise in association with a nerve that enters the bone through a nutrient canal (Fig. 7) (27). Just as in the present case, the tumor can also arise from a branch of the deep peroneal nerve and traverse to the nutrient canal of the first metatarsal. Histopathologic examination can help to establish the correct diagnosis. These tumors are composed of benign-appearing spindle cells that will be broadly distributed in 2 zones: the Antoni A zone, with spindle cells in a palisade formation surrounded by an interstitial substance that forms the Verocay bodies; and the Antoni B zone, which has irregular cells and a myxoid component (16). Both zones of cellularity have often been found in the same tumor (18). Although most lesions will contain both components, a predominance of Antoni B type tissue has been thought by some investigators to indicate aggressiveness along the spectrum from a neurilemmoma to a malignant tumor of the peripheral nerve sheath (28,29). In uncertain cases, immunochemical staining for S100 protein will be extremely valuable, because schwannomas will be diffusely positive for this marker (13). Curettage and bone grafting are probably adequate treatment for intraosseous schwannomas, because malignant changes have been rare (3,7,23). However, large lesions might require en bloc excision
1. Woodruff JM, Kourea HP, Louis DR, Scheithauer BW. Schwannoma. In: World Health Organization Classification of Tumors: Pathology and Genetics of Tumors of the Nervous System, pp. 164–166, edited by P Kleihues, WK Cavenee, IARC Press, Lyon, France, 2000. 2. Chi AC, Carey J, Muller S. Intraosseous schwannoma of the mandible: a case report and review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 96:54–65, 2003. 3. Mutema GK, Sorger J. Intraosseous schwannoma of the humerus. Skeletal Radiol 31:419–421, 2002. J, Calmet J, Sirvent JJ, Dome nech S. Intraosseous neurilemmoma of the radius: 4. Gine a case report. J Hand Surg Am 25:365–369, 2000. 5. Gordon EJ. Solitary intraosseous neurilemmoma of the tibia: review of intraosseous neurilemmoma and neurofibroma. Clin Orthop Relat Res 117:271–782, 1976. 6. Jain VK, Jain D, Kumar S. Proximal tibial epiphyseal intraosseous schwannoma a rare entity. J Pediatr Orthop 30:411, 2010. 7. Aoki J, Tanikawa H, Fujioka F, Ishii K, Seo GS, Karakida O, Sone S. Intraosseous neurilemmoma of the fibula. Skeletal Radiol 26:60–63, 1997. 8. Chevalier X, Montazel JL, Voisin MC, Hernigou P. Intraosseous neurilemmoma of the lower third of the fibula. AJR Am J Roentgenol 165:1555–1556, 1995. 9. Kim M-J, Choi J, Khang S-K, Kim J-S, Lee J-S, Cho K-J. Primary intraosseous melanotic schwannoma of the fibula associated with the Carney complex. Pathol Int 56:538–542, 2006. 10. Luk’ianchenko AB, Petrovichev NN, Ol’khovskaia IG. Neurilemmoma of the fibula (a case report). Vopr Onkol 30:91–93, 1984 [in Russian]. 11. Palocaren T, Walter NM, Madhuri V, Gibikote S. Schwannoma of the fibula. J Bone Joint Surg Br 90:803–805, 2008. 12. Sufian Z, Mazhar A, Lateef JZ, Rana SK. Intraosseous schwannoma of head of first metatarsal: a rare entity. Indian J Pathol Microbiol 52:286–288, 2009. 13. Randall R. Tumors in orthopedics. In: Current Diagnosis & Treatment in Orthopedicsed 3, Lange Medical Books/McGraw-Hill, New York, 2003, pp. 286–369. 14. World Health Organization Classification of Tumors: Pathology and Genetics: Tumors of Soft Tissue and Bone, edited by CDM Fletcher, KK Umni, F Mertens, IARC Press, Lyon, France, 2002. 15. Sadeghi EM, Koenig LJ, Clark D. Intrabony neurilemmoma: diagnosis and management. J Am Dent Assoc 129:729–732, 1998. 16. Monte SM, Dorfman HD, Chandra R, Malawer M. Intraosseous schwannoma: histologic features, ultrastructure, and review of the literature. Hum Pathol 15:551–558, 1984. 17. Samter TG, Vellios F, Shafer WG. Neurilemmoma of bone: report of 3 cases with a review of the literature. Radiology 75:215–222, 1960. 18. Ritt MJ, Bos KE. A very large neurilemmoma of the anterior interosseous nerve. J Hand Surg Br 16:98–100, 1991. 19. Grossman MR, Mandracchia VJ, Urbas WM, Mandracchia DM. Neurilemmoma of the posterior tibial nerve with an uncommon case presentation. J Foot Surg 31:219–224, 1992. 20. Wood MK, Erdmann MW, Davies DM. Malignant schwannoma mistakenly diagnosed as carpal tunnel syndrome. J Hand Surg Br 18:187–188, 1993. 21. Dunnick NR. Image interpretation session: 1999. Intraosseous malignant peripheral nerve sheath tumor (malignant schwannoma) in a patient with neurofibromatosis. Radiographics 20:271–273, 2000.
M.T. Ansari et al. / The Journal of Foot & Ankle Surgery 53 (2014) 335–339
22. Maini A, Tripathi M, Shekar NC, Malhotra A. Sciatic schwannoma of the thigh detected on bone scan: a case report. Clin Imaging 27:191–193, 2003. 23. Pyati PS, Sanzone AG. Intraosseous neurilemmoma of the calcaneus. Orthopedics 19:353–355, 1996. 24. Sanado L, Ruiz JL, Laidler L, Polo M. Femoral intraosseous neurilemmoma. Arch Orthop Trauma Surg 110:212–213, 1991. 25. Trinez G, Rozan R, Petit P, Donne Y, Delmaire M. Osseous schwannoma of the tibia. J Radiol Electrol Med Nucl 50(suppl 5):407, 1969. 26. Schultz E, Sapan MR, McHeffey-Atkinson B, Naidich JB, Arlen M. Case report 872: ‘ancient’ schwannoma (degenerated neurilemmoma). Skeletal Radiol 23:593–595, 1994.
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