1224
NEUROTHEKEOMA
9. Harrison JD, Eggleston DJ: Odontogenic myxoma of the maxilla: A case report and some interesting histological findings. Br J oral surg 11:43, 1973 IO. Harrison JD: Odontogenic myxoma: Ultrastructural and histochemical studies. J Clin Pathol 26570, 1973 11. Farman AG, Nortje CJ, Grotepass FW, et al: Myxofibroma of the jaws. Br J Oral Surg 153, 1977 12. Ha&ton PS, Simpson W, Craig RDP Myxoma of the mandible. A fibroblastic tumor. Oral Surg 46:396, 1978 13. Slootwea PJ. Van Den Bos T. Straks W: Glvcosaminoalvcans in myxima of jaw: A biochemical study. J-Oral Pathol-14:299, 1985 14. Goldblatt Ll: Ultrastructural study of an odontogenic myxoma. Oral Surg 42:206, 1976 15. Simes RJ. Barros RE. Klein-Szanto AJP. et al: Ultrastructure of an oddntogenic myxoma. Oral Surg 39:640, 1975 16. Westwood RM, Alexander RW, Bennett DE: Giant odontogenic myxolibroma. Report of a case with histological and ultrastructural studies and a review of the literature. Oral Surg 37: 83, 1974 17. Balogh G, Inovay J: Recurrent mandibular myxoma: Report of case. J Oral Surg 30: I2 1, 1972 18. Allen PS: Fibromyxoma of the mandible: Case report and radiographic considerations. J Am Dent Assoc IO I :930, 1980 19. Colbum JF, Epker BN: Myxoma of the mandibular condyleSurgical excision with immediate reconstruction. J Oral Surg 33:610, 1978 20. Davis RB, Baker RD, Alling CC: Odontogenic myxoma. J Oral Surg 36:610. 1978
OF THE ORAL CAVITY
21. Stewart SS, Baum SM, Arlen M, et al: Myxoma of the lower jaw. Oral Surg 36:800. 1973 22. Cherrick H: Current concepts in the treatment ofjaw pathology. 70th Annual AAOMS Meeting, Boston, MA, September 29October 3. 1988 23. Harris RJ, Garrow E, Spinnato G: Myxoma ofthe maxilla: Report of case. J Oral Surg 35:70. 1977 24. James DR, Lucas VS: Maxillary myxoma in a child of 1I months. J Craniomaxillofac Surg 15:42, 1987 25. Cohen PB, Gamble JW: Maxillary resection for odontogenic myxoma: Report of case. J Oral Surg 35573. 1977 26. Totten JR: Recurrence of a myxoma in a costochondral graft. Br J Oral Surg 20:63. 1982 27. Himmelfarb R, Adamo A: Myxoma treated by peripheral ostectomy. Six year follow-up. NY State Dent J 38:612, 1972 28. Adamo AK, Locricchio RC, Freedman P: Myxoma of the mandible treated by peripheral ostectomy and immediate reconstruction: Report of case. J Oral Surg 38:530, 1980 29. Petti NA, Weber FL, Miller MC: Resection of a mandibular myxoma via a sagittal ramus osteotomy. J Oral Maxillofac Surg 45:793, 1987 30. Rittersma J, Van Go01 AV: Surgical access to multicystic lesions by sag&al splitting of the lower jaw. J Maxillofac Surg 7:246. 1979 3 1. Wong GB: Surgical management of a large complex mandibular odontoma by unilateral sag&al split osteotomy. J Oral Maxillofac Surg 47: 179, 1989 32. Sachs SA: Surgical excision with peripheral ostectomy. A definite, yet conservative approach to the surgical management of ameloblastoma. Oral Maxillofac Clin North Am 3:99. I99 I
J OralMaxillofacSurg 50:1224-1226.1992
Neurothekeoma of the Oral Cavity: Case Report and Review of the Literature JOSE L. RODRIGUEZ-PERALTO,
MD,* AND ADEL
Neurothekeoma is an uncommon, benign soft-tissue tumor of nerve sheath origin that most often involves upper portions of the body such as the head, neck, and shoulder. ’ It usually arises in the dermis and subcutis and very rarely in mucous membranes. Only a few cases of intraoral neurothekeoma have been reported.2-6 A case of neurothekeoma of the buccal mucosa is described along with its histologic and immunohistochemical characteristics, and previous cases occurring in the oral cavity are reviewed. Received from the Department of Pathology, The University of Texas, M.D. Anderson Cancer Center, Houston. * Visiting Fellow, Head and Neck Pathology. t Associate Professor of Pathology, Department of Pathology. The University of Texas, M.D. Anderson Cancer Center, Houston. Address correspondence and reprint requests to Dr El-Naggar: The University ofTexas, M.D. Anderson Cancer Center, 15 I5 Holcombe Blvd, Box 85. Houston, TX 77030. 0 1992 American 0278-2391/92/501
Association l-001
of Oral and Maxillofacial
5$3.00/O
Surgeons
K. EL-NAGGAR,
MD-t
Report of Case A 46-year-old woman came for treatment with a 7-month history of a small, bluish, painful mass located in the right buccal mucosa. The nodule which was covered by intact mucosa, had shown very slow, progressive growth. The lesion was excised and submitted for histologic examination with the clinical diagnosis of fibroma or mucocele. Postoperative healing was satisfactory, and the patient was without evidence of recurrence 4 months later. On gross examination, the specimen consisted of a 2 X I-cm ellipse of mucosa with a firm central portion. On cut section, an g-mm, grayish, well-defined rubbery nodule was noted beneath the mucosal surface (Fig 1A). Microscopically, the tumor was circumscribed and composed of distinct lobules surrounded by delicate fibrous connective tissue septa (Fig 1B); each lobule consisted of fascicles of spindle or polygonal cells with eosinophilic cytoplasm (Fig 2). There was an abundant myxoid background matrix (Fig 3). Scattered benign multinucleated giant cells were seen within the lobules. No mitotic figures were present. Multiple groups of cells within the tumor stained positively with S-100 protein antibody. No immunoreactivity was found for epithelial mem-
RODRIGUEZ-PERALTO
AND EL-NAGGAR
1225
FIGURE 2. Epitheliod and fusiform neurothekeoma cells in a lobular architecture (hematoxylin-eosin stain, original magnification X250).
FIGURE 1. A. Photomicrograph showing a well-circumscribed neurothekeoma beneath an intact oral mucosa (hematoxylin-eosin stain, original magnification X4). B, Photomicrograph showing microlobulation. There is both compact and loose arrangement of the constituent cells (hematoxylin-eosin stain, original magnification x 100).
brane antigen, tigens.
smooth
neurothekeoma in 1980 by Gallager and Helwig.’ Only seven of these rare tumors have been reported in the oral cavity 2-6;three tumors involved the tongue,3v4,6one the retromolar area,2 one the palate,’ and two the buccal mucosa.2’4 There was an additional case mentioned in the Gallager and Helwig’ series, but no clinical or pathologic data were provided. Mason et al” have also reported a case in the dermal area of the lower lip; since this neurothekeoma did not arise in oral mucosa, it was excluded from this review. The clinicopathologic characteristics of the oral neoplasms, along with our case, are presented in Table 1. The mean age of patients with oral neurothekeoma was 33 years; they were older than patients with cutaneous neurothekeomas (2 1.6 years).’ The tumors
muscle actin, or keratin cocktail an-
Discussion Tumors arising from peripheral nerves in the oral cavity are uncommon. Of 303 neural tumors reviewed by Wright and Jackson5 only 30 patients had neoplasms involving the oral cavity. The majority were neurilemomas or neurofibromas5; only one neurothekeoma was reported in this large series. On the other hand, none of 70 cases of nerve sheath myxoma reported by Pulitzer and Reed’ were located in the oral cavity. Neurothekeoma is a rare, benign, nerve sheath tumor first described in 1969 by Harkin and Reed’ under the term myxoma of nerve sheath, and designated as
FIGURE 3. Myxoid region with fusiform cells (hematoxylin-eosin stain, original magnification X250).
1226
NEUROTHEKEOMA
Table 1.
OF THE ORAL CAVITY
Newothekeomas of the Oral Cavity
Investigators Sist and Greene’ Mincer and Spears3 Tomich4 Wright and Jackson’ Yamamoto and Kawana“ Gallager and Helwig’ Present case
Age (yr)/Sex
Size (cm)
Location
30/F 41/F 23/M 45/M --/F 15/F 41/F -/46/F
0.5
Retromolar area Buccal mucosa Tongue Tongue Buccal mucosa Palate Tongue Buccal mucosa Buccal mucosa
1.0 0.8 x 0.6 x 0.4 0.8
Follow-up A&W 2 years
A&W 7 months NK NK NK NK A&W 9 months A&W 4 months
Duration
S- IO0 Protein Immunoreactivity
1 Year -
No No No No No No Yes -
I Months
Yes
1 Year 6 Months Several months 2 Months I Year -
Abbreviations: A&W. alive and well: NK, not known.
(oral and cutaneous) affected women more often than men.7,9 All neurothekeomas, dermal and oral, have been 1 cm or smaller at the time of surgical removal; all have been treated by excision. No recurrences have been recorded with the oral tumors. The few “recurrences” associated with cutaneous tumors more likely are persistent tumors, since they have resulted from incomplete excision of the primary lesion.7.9 Neurothekeomas manifest a characteristic histologic appearance prompted by their multifascicular and myxoid features. S- 100 protein antigen immunoreactivity is not constant’ ‘-14;whether this is due to variable differentiation in the precursor (Schwann, perineural) cells is unknown.” The differential diagnosis includes focal mucinosis, myxoid neurofibroma, perineurioma, myxoma, and some soft-tissue sarcomas with myxomatous areas. Mucinosis is not circumscribed, lobulated, or as cellular as neurothekeoma. Intralesional neurites and wire-like collagen bundles found in neurofibromas distinguish them from neurothekeomas. The perineurioma is epithelial-membrane-antigen immunoreactive, and S100 protein antigen is negative.16 Since it is composed almost exclusively of perineural cells, the tumor also lacks the distinctive lobulated structure of neurothekeoma.” Oral myxomas also do not have a lobular pattern, and are invariably unreactive with antibodies against S-100 protein antigen.” Sarcomas with myxoid areas are more deeply located and exhibit distinguishing pleomorphic, anaplastic. and mitotic features. References I. Enzinger FM, Weiss SW: Soft Tissue Tumors (ed 2). Washington, DC, Mosby, 1988, pp 769-770
2. Sist TC, Greene GW: Benign nerve sheath myxoma: Light and electron microscopic features of two cases. Oral Surg Oral Med Oral Pathol47:441, 1979 3. Mincer HH, Spears KD: Nerve sheath myxoma in the tongue. Oral Surg 37:428, 1974 4. Tomich CE: Oral focal mucinosis. A clinicopathologic and histochemical study of eight cases. Oral Surg 38:714, 1974 5. Wright BA, Jackson D: Neural tumors ofthe oral cavity: A review of the spectrum of benign and malignant oral tumors of the oral cavity and jaws. Oral Sung 49:509, 1980 6. Yamamoto H, Kawana T: Oral nerve sheath myxoma: Report of a case with finding of ultrastructural and immunohistochemical studies. Acta Pathol Jpn 38: 12 1, 1988 7. Pulitzer DR, Reed RJ: Nerve-sheath myxoma (perineural mixoma). Am J Dermatopathol 7:409. 1985 8. Harkin JC, Reed RJ: Tumors of the Peripheral Nervous System, second series, fascicle 3. Washington, DC, Armed Forces Institute of Pathology, 1969, pp 60-64 9. Gallagher RL, Helwig EB: Neurothekeoma-A benign cutaneous tumor of neural origin. Am J Clin Pathol 74:759, 1980 10. Mason MR, Gnepp DR, Herbold DR: Nerve sheath myxoma (neurothekeoma): A case involving the lip. Oral Surg Oral Med Oral Patho162: 185, 1986 I 1. Blumbcrg AK, Kay S, Adelaar RS: Nerve sheath myxoma of digital nerve. Cancer 63:1215, 1989 12. Schmitt FC, Bacchi CE: S-100 protein: Is it useful as a tumor marker in diagnostic immunocytochemistry? Histopathology 15:281, 1989 13. Aronson PJ. Fretzin DF, Potter BS: Neurothekeoma of Gallager and Helwig (dermal nerve sheath myxoma variant): Report of a case with electron microscopic and immunohistochemical studies. J Cutan Pathol 12:506, I985 14. Weiss SW. Langloss JM. Enzinger FM: Value of S-100 protein in the diagnosis of soft tissue tumor with particular reference to benign and malignant Schwann cell tumors. Lab Invest 49: 299, 1983 15. Paulus W, Jellinger K, Pemeczky G: Intraspinal neurothekeoma (nerve sheath myxoma). A report of two cases. Am J Clin Pathol95:511, 1991 16. Ariza A, Bilbao JM, Rosai J: Immunohistochemical detection of epithelial membrane antigen in normal p&neural cells and perineurioma. Am J Surg Path01 I2:678, 1988 17. Ohno T, Park P, Akai M, et al: Ultrastructural study of a perineurioma. Ultrastruct Path01 12:495, 1988 18. Miettinen M, Hoeckerstedt K. Reitamo J, et al: Intramuscular myxoma: A clinicopathological study of twenty-three cases. Am J Clin Path01 84:265. 1985
NEUROTHEKEOMA
9. Harrison JD, Eggleston DJ: Odontogenic myxoma of the maxilla: A case report and some interesting histological findings. Br J oral surg 11:43, 1973 IO. Harrison JD: Odontogenic myxoma: Ultrastructural and histochemical studies. J Clin Pathol 26570, 1973 11. Farman AG, Nortje CJ, Grotepass FW, et al: Myxofibroma of the jaws. Br J Oral Surg 153, 1977 12. Ha&ton PS, Simpson W, Craig RDP Myxoma of the mandible. A fibroblastic tumor. Oral Surg 46:396, 1978 13. Slootwea PJ. Van Den Bos T. Straks W: Glvcosaminoalvcans in myxima of jaw: A biochemical study. J-Oral Pathol-14:299, 1985 14. Goldblatt Ll: Ultrastructural study of an odontogenic myxoma. Oral Surg 42:206, 1976 15. Simes RJ. Barros RE. Klein-Szanto AJP. et al: Ultrastructure of an oddntogenic myxoma. Oral Surg 39:640, 1975 16. Westwood RM, Alexander RW, Bennett DE: Giant odontogenic myxolibroma. Report of a case with histological and ultrastructural studies and a review of the literature. Oral Surg 37: 83, 1974 17. Balogh G, Inovay J: Recurrent mandibular myxoma: Report of case. J Oral Surg 30: I2 1, 1972 18. Allen PS: Fibromyxoma of the mandible: Case report and radiographic considerations. J Am Dent Assoc IO I :930, 1980 19. Colbum JF, Epker BN: Myxoma of the mandibular condyleSurgical excision with immediate reconstruction. J Oral Surg 33:610, 1978 20. Davis RB, Baker RD, Alling CC: Odontogenic myxoma. J Oral Surg 36:610. 1978
OF THE ORAL CAVITY
21. Stewart SS, Baum SM, Arlen M, et al: Myxoma of the lower jaw. Oral Surg 36:800. 1973 22. Cherrick H: Current concepts in the treatment ofjaw pathology. 70th Annual AAOMS Meeting, Boston, MA, September 29October 3. 1988 23. Harris RJ, Garrow E, Spinnato G: Myxoma ofthe maxilla: Report of case. J Oral Surg 35:70. 1977 24. James DR, Lucas VS: Maxillary myxoma in a child of 1I months. J Craniomaxillofac Surg 15:42, 1987 25. Cohen PB, Gamble JW: Maxillary resection for odontogenic myxoma: Report of case. J Oral Surg 35573. 1977 26. Totten JR: Recurrence of a myxoma in a costochondral graft. Br J Oral Surg 20:63. 1982 27. Himmelfarb R, Adamo A: Myxoma treated by peripheral ostectomy. Six year follow-up. NY State Dent J 38:612, 1972 28. Adamo AK, Locricchio RC, Freedman P: Myxoma of the mandible treated by peripheral ostectomy and immediate reconstruction: Report of case. J Oral Surg 38:530, 1980 29. Petti NA, Weber FL, Miller MC: Resection of a mandibular myxoma via a sagittal ramus osteotomy. J Oral Maxillofac Surg 45:793, 1987 30. Rittersma J, Van Go01 AV: Surgical access to multicystic lesions by sag&al splitting of the lower jaw. J Maxillofac Surg 7:246. 1979 3 1. Wong GB: Surgical management of a large complex mandibular odontoma by unilateral sag&al split osteotomy. J Oral Maxillofac Surg 47: 179, 1989 32. Sachs SA: Surgical excision with peripheral ostectomy. A definite, yet conservative approach to the surgical management of ameloblastoma. Oral Maxillofac Clin North Am 3:99. I99 I
J OralMaxillofacSurg 50:1224-1226.1992
Neurothekeoma of the Oral Cavity: Case Report and Review of the Literature JOSE L. RODRIGUEZ-PERALTO,
MD,* AND ADEL
Neurothekeoma is an uncommon, benign soft-tissue tumor of nerve sheath origin that most often involves upper portions of the body such as the head, neck, and shoulder. ’ It usually arises in the dermis and subcutis and very rarely in mucous membranes. Only a few cases of intraoral neurothekeoma have been reported.2-6 A case of neurothekeoma of the buccal mucosa is described along with its histologic and immunohistochemical characteristics, and previous cases occurring in the oral cavity are reviewed. Received from the Department of Pathology, The University of Texas, M.D. Anderson Cancer Center, Houston. * Visiting Fellow, Head and Neck Pathology. t Associate Professor of Pathology, Department of Pathology. The University of Texas, M.D. Anderson Cancer Center, Houston. Address correspondence and reprint requests to Dr El-Naggar: The University ofTexas, M.D. Anderson Cancer Center, 15 I5 Holcombe Blvd, Box 85. Houston, TX 77030. 0 1992 American 0278-2391/92/501
Association l-001
of Oral and Maxillofacial
5$3.00/O
Surgeons
K. EL-NAGGAR,
MD-t
Report of Case A 46-year-old woman came for treatment with a 7-month history of a small, bluish, painful mass located in the right buccal mucosa. The nodule which was covered by intact mucosa, had shown very slow, progressive growth. The lesion was excised and submitted for histologic examination with the clinical diagnosis of fibroma or mucocele. Postoperative healing was satisfactory, and the patient was without evidence of recurrence 4 months later. On gross examination, the specimen consisted of a 2 X I-cm ellipse of mucosa with a firm central portion. On cut section, an g-mm, grayish, well-defined rubbery nodule was noted beneath the mucosal surface (Fig 1A). Microscopically, the tumor was circumscribed and composed of distinct lobules surrounded by delicate fibrous connective tissue septa (Fig 1B); each lobule consisted of fascicles of spindle or polygonal cells with eosinophilic cytoplasm (Fig 2). There was an abundant myxoid background matrix (Fig 3). Scattered benign multinucleated giant cells were seen within the lobules. No mitotic figures were present. Multiple groups of cells within the tumor stained positively with S-100 protein antibody. No immunoreactivity was found for epithelial mem-
RODRIGUEZ-PERALTO
AND EL-NAGGAR
1225
FIGURE 2. Epitheliod and fusiform neurothekeoma cells in a lobular architecture (hematoxylin-eosin stain, original magnification X250).
FIGURE 1. A. Photomicrograph showing a well-circumscribed neurothekeoma beneath an intact oral mucosa (hematoxylin-eosin stain, original magnification X4). B, Photomicrograph showing microlobulation. There is both compact and loose arrangement of the constituent cells (hematoxylin-eosin stain, original magnification x 100).
brane antigen, tigens.
smooth
neurothekeoma in 1980 by Gallager and Helwig.’ Only seven of these rare tumors have been reported in the oral cavity 2-6;three tumors involved the tongue,3v4,6one the retromolar area,2 one the palate,’ and two the buccal mucosa.2’4 There was an additional case mentioned in the Gallager and Helwig’ series, but no clinical or pathologic data were provided. Mason et al” have also reported a case in the dermal area of the lower lip; since this neurothekeoma did not arise in oral mucosa, it was excluded from this review. The clinicopathologic characteristics of the oral neoplasms, along with our case, are presented in Table 1. The mean age of patients with oral neurothekeoma was 33 years; they were older than patients with cutaneous neurothekeomas (2 1.6 years).’ The tumors
muscle actin, or keratin cocktail an-
Discussion Tumors arising from peripheral nerves in the oral cavity are uncommon. Of 303 neural tumors reviewed by Wright and Jackson5 only 30 patients had neoplasms involving the oral cavity. The majority were neurilemomas or neurofibromas5; only one neurothekeoma was reported in this large series. On the other hand, none of 70 cases of nerve sheath myxoma reported by Pulitzer and Reed’ were located in the oral cavity. Neurothekeoma is a rare, benign, nerve sheath tumor first described in 1969 by Harkin and Reed’ under the term myxoma of nerve sheath, and designated as
FIGURE 3. Myxoid region with fusiform cells (hematoxylin-eosin stain, original magnification X250).
1226
NEUROTHEKEOMA
Table 1.
OF THE ORAL CAVITY
Newothekeomas of the Oral Cavity
Investigators Sist and Greene’ Mincer and Spears3 Tomich4 Wright and Jackson’ Yamamoto and Kawana“ Gallager and Helwig’ Present case
Age (yr)/Sex
Size (cm)
Location
30/F 41/F 23/M 45/M --/F 15/F 41/F -/46/F
0.5
Retromolar area Buccal mucosa Tongue Tongue Buccal mucosa Palate Tongue Buccal mucosa Buccal mucosa
1.0 0.8 x 0.6 x 0.4 0.8
Follow-up A&W 2 years
A&W 7 months NK NK NK NK A&W 9 months A&W 4 months
Duration
S- IO0 Protein Immunoreactivity
1 Year -
No No No No No No Yes -
I Months
Yes
1 Year 6 Months Several months 2 Months I Year -
Abbreviations: A&W. alive and well: NK, not known.
(oral and cutaneous) affected women more often than men.7,9 All neurothekeomas, dermal and oral, have been 1 cm or smaller at the time of surgical removal; all have been treated by excision. No recurrences have been recorded with the oral tumors. The few “recurrences” associated with cutaneous tumors more likely are persistent tumors, since they have resulted from incomplete excision of the primary lesion.7.9 Neurothekeomas manifest a characteristic histologic appearance prompted by their multifascicular and myxoid features. S- 100 protein antigen immunoreactivity is not constant’ ‘-14;whether this is due to variable differentiation in the precursor (Schwann, perineural) cells is unknown.” The differential diagnosis includes focal mucinosis, myxoid neurofibroma, perineurioma, myxoma, and some soft-tissue sarcomas with myxomatous areas. Mucinosis is not circumscribed, lobulated, or as cellular as neurothekeoma. Intralesional neurites and wire-like collagen bundles found in neurofibromas distinguish them from neurothekeomas. The perineurioma is epithelial-membrane-antigen immunoreactive, and S100 protein antigen is negative.16 Since it is composed almost exclusively of perineural cells, the tumor also lacks the distinctive lobulated structure of neurothekeoma.” Oral myxomas also do not have a lobular pattern, and are invariably unreactive with antibodies against S-100 protein antigen.” Sarcomas with myxoid areas are more deeply located and exhibit distinguishing pleomorphic, anaplastic. and mitotic features. References I. Enzinger FM, Weiss SW: Soft Tissue Tumors (ed 2). Washington, DC, Mosby, 1988, pp 769-770
2. Sist TC, Greene GW: Benign nerve sheath myxoma: Light and electron microscopic features of two cases. Oral Surg Oral Med Oral Pathol47:441, 1979 3. Mincer HH, Spears KD: Nerve sheath myxoma in the tongue. Oral Surg 37:428, 1974 4. Tomich CE: Oral focal mucinosis. A clinicopathologic and histochemical study of eight cases. Oral Surg 38:714, 1974 5. Wright BA, Jackson D: Neural tumors ofthe oral cavity: A review of the spectrum of benign and malignant oral tumors of the oral cavity and jaws. Oral Sung 49:509, 1980 6. Yamamoto H, Kawana T: Oral nerve sheath myxoma: Report of a case with finding of ultrastructural and immunohistochemical studies. Acta Pathol Jpn 38: 12 1, 1988 7. Pulitzer DR, Reed RJ: Nerve-sheath myxoma (perineural mixoma). Am J Dermatopathol 7:409. 1985 8. Harkin JC, Reed RJ: Tumors of the Peripheral Nervous System, second series, fascicle 3. Washington, DC, Armed Forces Institute of Pathology, 1969, pp 60-64 9. Gallagher RL, Helwig EB: Neurothekeoma-A benign cutaneous tumor of neural origin. Am J Clin Pathol 74:759, 1980 10. Mason MR, Gnepp DR, Herbold DR: Nerve sheath myxoma (neurothekeoma): A case involving the lip. Oral Surg Oral Med Oral Patho162: 185, 1986 I 1. Blumbcrg AK, Kay S, Adelaar RS: Nerve sheath myxoma of digital nerve. Cancer 63:1215, 1989 12. Schmitt FC, Bacchi CE: S-100 protein: Is it useful as a tumor marker in diagnostic immunocytochemistry? Histopathology 15:281, 1989 13. Aronson PJ. Fretzin DF, Potter BS: Neurothekeoma of Gallager and Helwig (dermal nerve sheath myxoma variant): Report of a case with electron microscopic and immunohistochemical studies. J Cutan Pathol 12:506, I985 14. Weiss SW. Langloss JM. Enzinger FM: Value of S-100 protein in the diagnosis of soft tissue tumor with particular reference to benign and malignant Schwann cell tumors. Lab Invest 49: 299, 1983 15. Paulus W, Jellinger K, Pemeczky G: Intraspinal neurothekeoma (nerve sheath myxoma). A report of two cases. Am J Clin Pathol95:511, 1991 16. Ariza A, Bilbao JM, Rosai J: Immunohistochemical detection of epithelial membrane antigen in normal p&neural cells and perineurioma. Am J Surg Path01 I2:678, 1988 17. Ohno T, Park P, Akai M, et al: Ultrastructural study of a perineurioma. Ultrastruct Path01 12:495, 1988 18. Miettinen M, Hoeckerstedt K. Reitamo J, et al: Intramuscular myxoma: A clinicopathological study of twenty-three cases. Am J Clin Path01 84:265. 1985
