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Schwannoma of the upper lip: case report and literature review
Schwannoma of the Upper Lip: Case Report and Literature Review Shih-Wei Yang, MD,* and Chin-Yew Lin, MD† Schwannomas, arising from nerve-sheath Schwann cells, rarely occur in the lip area. A Medline search in English literature from 1966 to 2002 revealed only 6 documented cases of schwannomas of the lip. We report the unusual case of a 22-year-old female patient who developed a schwannoma of the upper lip. Histopathological examination and immunohistochemical staining studies were performed, with the relevant literature for this clinical rarity also reviewed. Complete enucleation of the schwannoma usually achieves cure. Although very rare, schwannoma should be taken into consideration in the differential diagnosis of any upper lip mass. (Am J Otolaryngol 2003;24:351-354. © 2003 Elsevier Inc. All rights reserved.)
Schwannomas, also known as neurilemmomas, are benign nerve-sheath tumors arising from perineural Schwann cells of the nerve sheath and occur along any somatic or sympathetic nerve. Approximately 25% to 45% of schwannomas occur in the head and neck.1 Although onset age ranges from 1 to 89 years, the tumors are usually seen in the fourth decade of life.2 We report a rare case of benign schwannoma of the upper lip. To our knowledge, only 6 such cases have been documented in the English literature.3-6 Although malignant transformation of a benign schwannoma of the lip has been controversial, it remains a concern. CASE REPORT A 22-year-old Taiwanese woman visited the outpatient department of our hospital for a painless mass on her upper lip. She had first noticed the lesion 2 years previously, with the tumor growing noticeably during the 3 preceding months. Physical examination revealed an oval, smooth-surfaced, nontender mass measuring 0.9 ⫻ 0.5 cm located in the
From the Departments of *Otolaryngology Head and Neck Surgery and †Pathology, Chang Gung Memorial Hospital, Keelung, Taiwan. Address correspondence to: Chin-Yew Lin, MD, Department of Pathology, Chang Gung Memorial Hospital, Keelung No 222 Mai Chin Road, Keelung City, Taiwan. E-mail: [email protected]. © 2003 Elsevier Inc. All rights reserved. 0196-0709/03/2405-0000$30.00/0 doi:10.1016/S0196-0709(03)00065-6
medial portion of the vermilion area of the upper lip. The patient had no stigmata, and family history of neurofibromatosis was denied. Past history was unremarkable. The results of all the laboratory tests were within normal limits. The mass was completely excised under local anesthesia. Grossly, the specimen revealed an entirely encapsulated tumor mass measuring 0.9 ⫻ 0.5 cm (Fig 1), with a soft and grayish-white surface. On microscopic examination of the encapsulated nodule, peripheral hypercellular (Antoni A) and central hypocellular (Antoni B) regions were noted (Fig 2). In the Antoni A area, typical Verocay bodies, which are composed of palisading nuclei around spaces filled with eosinophilic filaments, were identified (Fig 3). Mitosis and necrosis were not detected. Alternatively, a loosely textured matrix was determined for the Antoni B tissue, with areas of edema, myxomatous changes, cystic degeneration, and the presence of dilated hyalined vessels (Fig 4). Immunohistochemical staining was strongly positive for S-100 protein and negative for desmin, smooth muscle actin, and C-kit protein (CD117; DAKO, Copenhagen, Denmark). The postoperative course was uneventful, with the patient remaining free of disease after 2 years of follow-up. DISCUSSION Schwannomas, also known as neurilemmomas, are uncommon tumors that arise predominantly from peripheral nerves in rela-
American Journal of Otolaryngology, Vol 24, No 5 (September-October), 2003: pp 351-354
351
352
Fig 1. Encapsulation of the tumor (T) within the stroma tissue of the lip. The epithelial lining (E) and surrounding fibrous capsule (arrow) of the tumor show no remarkable change (hematoxylin and eosin stain, 1ⴛ).
tively deep parts of the soft tissues such as the posterior spinal root; the acoustic nerve; the extremities; and the body, trunk, and neck.7 They do not arise from cranial nerves I and II, however, because these nerves lack Schwann cells.8 The tumors frequently arise in the head and neck region because of its unique anatomical composition, with the parapharyngeal space of the neck as the most common site of occurrence.9 Schwannomas are characterized by solitary occurrence, slow growth, and smooth surface.2 The clinical symptomatology of schwannomas is variable and depends
Fig 2. Photomicrography showing an encapsulated tumor (arrow) with hypercellular Antoni A (A) and hypocellular Antoni B (B) regions. Secondary changes, including hyaline vessels, edema, and hemorrhage, are noted in the Antoni B area. An unremarkable epithelial lining (E) is also shown (hematoxylin and eosin stain, 40ⴛ).
YANG AND LIN
Fig 3. Verocay bodies (arrowhead) in the Antoni A area are shown in this high-magnification photomicrograph. Neither marked nuclear pleomorphism nor mitosis is identified (hematoxylin and eosin stain, 400ⴛ).
on the nerve of origin. Most instances are typically asymptomatic. First described by Das Gupta et al3 in 1969, schwannoma of the lip is a rare clinical entity. A Medline search of the English literature revealed only 6 reported cases.3-6 Table 1 summarizes the salient features of the previously reported neurilemmomas as well as those for the reported subject. Microscopically, the characteristic histological features for a schwannoma of the lip are similar to those described for analogs found at other sites. These include complete tumor encapsulation and composition consisting of alternating regions of hypercellularity and hypocellularity known as Antoni A and Antoni B areas, respectively.1-6,8-10 In general, the rel-
Fig 4. Dilated and congested vessels (arrow) with areas of edema and hemorrhage in the Antoni B areas were shown (hematoxylin and eosin stain, 200ⴛ).
SCHWANNOMA OF THE UPPER LIP
353
TABLE 1. Reported Cases of Benign Schwannomas of the Lip Authors (Year)
Number of Case(s)
Age (y)
Sex
Location
Treatment
Follow-up
3 1 1 1 1
NA NA 36 20 22
NA NA Man Woman Woman
NA NA Upper lip Upper lip Upper lip
NA NA Excision biopsy NA Excision biopsy
NA NA NA NA 2 years
3
Das Gupta et al (1969) Cherrick et al4 (1971) Barbosa et al5 (1984) Asaumi et al6 (2000) Present case Abbreviation: NA, data not available.
ative proportions of the 2 regions vary to the extent that either may occupy nearly the entire tumor. Usually, the hypercellular Antoni A region consists of monomorphic spindleshaped Schwann cells with pointed basophilic nuclei and poorly defined eosinophilic cytoplasm. On occasion, however, Verocay bodies, made up of palisading spindle-shaped cells around eosinophilic fibrils, are present in the Antoni A area, as noted in our case (Fig. 3).4,5 Further, secondary changes, such as cystic degeneration, vessels with thick hyaline walls and hemorrhage (Fig. 4), may occur in the Antoni B tissue.1,2,5,8 These secondary changes were also observed in our patient. Rarely, mild nuclear pleomorphism and few normal mitotic figures are identified, especially in the Antoni A area; however, this does not necessarily indicate malignant change.2 Immunohistochemically, negative results for desmin, smooth muscle actin and C-kit protein exclude the possibility of smooth-muscle and stromal tumors.1 Intense S-100 protein immunoreactivity for cytoplasmic and nuclear patterns indicates neural origin.1,6 These staining results and the associated H & E microscopic findings confirmed the diagnosis of schwannoma in the reported case. The involved nerves are frequently of particular interest to the clinicians. For example, the nerves most commonly involved in schwannomas in the parapharyngeal space are the vagus and the cervical sympathetic chain.10 The cutaneous branches of the infraorbital nerve are widely distributed throughout the upper lip, medial portion of the cheek, lower eyelid, and the side of the nose. In the present case, schwannoma of the upper lip may have arisen from a branch of the infraorbital nerve or of cranial nerve V. Asaumi et al6 have reported the findings for
ultrasound, computed tomography, and magnetic resonance imaging for a schwannoma of the upper lip. Homogeneous, hypoechoic features and posterior acoustic enhancement were noted on ultrasound. The computed tomography scan revealed a homogenous softtissue density mass, with a clear margin. By contrast, the magnetic resonance imaging showed a homogenous lesion with low-intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted images. In our case, however, radiologic examination was not arranged because the lesion was relatively small. The prognosis of schwannoma is quite favorable. Conservative surgical removal is the treatment of choice, with wide excision not advocated. If complete enucleation is achieved, no recurrence should be expected.2,5,8,10 Malignant transformation of benign schwannoma has been controversial; some authors are doubtful of its occurrence, although a few isolated cases have been documented.5,8,11 The diagnosis was not considered for our patient because examination of the excised mass revealed benign microscopic features and confirmed complete removal. In summary, schwannoma of the upper lip is a clinical rarity. Complete enucleation usually achieves cure. Malignant transformation of a benign schwannoma remains the major concern. Although very rare, schwannoma should be taken into consideration in the differential diagnosis of an upper lip mass. REFERENCES 1. Thurnher D, Quint C, Pammer J, et al: Dysphagia due to a large schwannoma of the oropharynx: Case report and review of the literature. Arch Otolaryngol Head Neck Surg 128:850-852, 2002
354
2. Bildirici K, Cakli H, Kecik C, et al: Schwannoma (neurilemmoma) of the palatine tonsil. Otolaryngol Head Neck Surg 126:693-694, 2002 3. Das Gupta TK, Brasfield RD, Strong EW, et al: Benign solitary Schwannomas (neurilemomas). Cancer 24:355366, 1969 4. Cherrick HM, Eversole LR: Benign neural sheath neoplasm of the oral cavity. Report of thirty-seven cases. Oral Surg Oral Med Oral Pathol 32:900-909, 1971 5. Barbosa J, Hansen LS: Solitary multilobular schwannoma of the oral cavity. J Oral Med 39:232-235, 1984 6. Asaumi J, Konouchi H, Kishi K: Schwannoma of the upper lip: ultrasound, CT, and MRI findings. J Oral Maxillofac Surg 58:1173-1175, 2000 7. Kara CO, Topuz B: Horner’s syndrome after excision of cervical sympathetic chain schwannoma. Otolaryngo Head Neck Surg 127:127-128, 2002 8. Michida A, Ryoke K, Ishikura S, et al: Multiple schwannomas of the neck, mediastinum, and parapha-
YANG AND LIN
ryngeal space: Report of case. J Oral Maxillofal Surg 53:617-620, 1995 9. Triaridis C, Tsalighopoulos MG, Kouloulas A, et al: Posterior pharyngeal wall schwannoma. J Laryngo Otol 101:749-752, 1987 10. Rosner M, Fisher W, Mulligan L: Cervical sympathetic schwannoma: Case report. Neurosurgery 49:14521454, 2001 11. Shibata Y, Ueda T, Seki H, et al: Gastrointestinal stromal tumour of the rectum. Eur J Gastroenterol Hepatol 13:283-286, 2001 12. Mikami Y, Hidaka T, Akisada T, et al: Malignant peripheral nerve sheath tumor arising in benign ancient schwannoma: A case report with an immunohistochemical study. Pathol Int 50:156-161, 2000 13. Woodruff JM, Selig AM, Crowley K, et al: Schwannoma (Neurilemoma) with malignant transformation. Am J Surg Pathol 18:882-895, 1994
Schwannomas, also known as neurilemmomas, are benign nerve-sheath tumors arising from perineural Schwann cells of the nerve sheath and occur along any somatic or sympathetic nerve. Approximately 25% to 45% of schwannomas occur in the head and neck.1 Although onset age ranges from 1 to 89 years, the tumors are usually seen in the fourth decade of life.2 We report a rare case of benign schwannoma of the upper lip. To our knowledge, only 6 such cases have been documented in the English literature.3-6 Although malignant transformation of a benign schwannoma of the lip has been controversial, it remains a concern. CASE REPORT A 22-year-old Taiwanese woman visited the outpatient department of our hospital for a painless mass on her upper lip. She had first noticed the lesion 2 years previously, with the tumor growing noticeably during the 3 preceding months. Physical examination revealed an oval, smooth-surfaced, nontender mass measuring 0.9 ⫻ 0.5 cm located in the
From the Departments of *Otolaryngology Head and Neck Surgery and †Pathology, Chang Gung Memorial Hospital, Keelung, Taiwan. Address correspondence to: Chin-Yew Lin, MD, Department of Pathology, Chang Gung Memorial Hospital, Keelung No 222 Mai Chin Road, Keelung City, Taiwan. E-mail: [email protected]. © 2003 Elsevier Inc. All rights reserved. 0196-0709/03/2405-0000$30.00/0 doi:10.1016/S0196-0709(03)00065-6
medial portion of the vermilion area of the upper lip. The patient had no stigmata, and family history of neurofibromatosis was denied. Past history was unremarkable. The results of all the laboratory tests were within normal limits. The mass was completely excised under local anesthesia. Grossly, the specimen revealed an entirely encapsulated tumor mass measuring 0.9 ⫻ 0.5 cm (Fig 1), with a soft and grayish-white surface. On microscopic examination of the encapsulated nodule, peripheral hypercellular (Antoni A) and central hypocellular (Antoni B) regions were noted (Fig 2). In the Antoni A area, typical Verocay bodies, which are composed of palisading nuclei around spaces filled with eosinophilic filaments, were identified (Fig 3). Mitosis and necrosis were not detected. Alternatively, a loosely textured matrix was determined for the Antoni B tissue, with areas of edema, myxomatous changes, cystic degeneration, and the presence of dilated hyalined vessels (Fig 4). Immunohistochemical staining was strongly positive for S-100 protein and negative for desmin, smooth muscle actin, and C-kit protein (CD117; DAKO, Copenhagen, Denmark). The postoperative course was uneventful, with the patient remaining free of disease after 2 years of follow-up. DISCUSSION Schwannomas, also known as neurilemmomas, are uncommon tumors that arise predominantly from peripheral nerves in rela-
American Journal of Otolaryngology, Vol 24, No 5 (September-October), 2003: pp 351-354
351
352
Fig 1. Encapsulation of the tumor (T) within the stroma tissue of the lip. The epithelial lining (E) and surrounding fibrous capsule (arrow) of the tumor show no remarkable change (hematoxylin and eosin stain, 1ⴛ).
tively deep parts of the soft tissues such as the posterior spinal root; the acoustic nerve; the extremities; and the body, trunk, and neck.7 They do not arise from cranial nerves I and II, however, because these nerves lack Schwann cells.8 The tumors frequently arise in the head and neck region because of its unique anatomical composition, with the parapharyngeal space of the neck as the most common site of occurrence.9 Schwannomas are characterized by solitary occurrence, slow growth, and smooth surface.2 The clinical symptomatology of schwannomas is variable and depends
Fig 2. Photomicrography showing an encapsulated tumor (arrow) with hypercellular Antoni A (A) and hypocellular Antoni B (B) regions. Secondary changes, including hyaline vessels, edema, and hemorrhage, are noted in the Antoni B area. An unremarkable epithelial lining (E) is also shown (hematoxylin and eosin stain, 40ⴛ).
YANG AND LIN
Fig 3. Verocay bodies (arrowhead) in the Antoni A area are shown in this high-magnification photomicrograph. Neither marked nuclear pleomorphism nor mitosis is identified (hematoxylin and eosin stain, 400ⴛ).
on the nerve of origin. Most instances are typically asymptomatic. First described by Das Gupta et al3 in 1969, schwannoma of the lip is a rare clinical entity. A Medline search of the English literature revealed only 6 reported cases.3-6 Table 1 summarizes the salient features of the previously reported neurilemmomas as well as those for the reported subject. Microscopically, the characteristic histological features for a schwannoma of the lip are similar to those described for analogs found at other sites. These include complete tumor encapsulation and composition consisting of alternating regions of hypercellularity and hypocellularity known as Antoni A and Antoni B areas, respectively.1-6,8-10 In general, the rel-
Fig 4. Dilated and congested vessels (arrow) with areas of edema and hemorrhage in the Antoni B areas were shown (hematoxylin and eosin stain, 200ⴛ).
SCHWANNOMA OF THE UPPER LIP
353
TABLE 1. Reported Cases of Benign Schwannomas of the Lip Authors (Year)
Number of Case(s)
Age (y)
Sex
Location
Treatment
Follow-up
3 1 1 1 1
NA NA 36 20 22
NA NA Man Woman Woman
NA NA Upper lip Upper lip Upper lip
NA NA Excision biopsy NA Excision biopsy
NA NA NA NA 2 years
3
Das Gupta et al (1969) Cherrick et al4 (1971) Barbosa et al5 (1984) Asaumi et al6 (2000) Present case Abbreviation: NA, data not available.
ative proportions of the 2 regions vary to the extent that either may occupy nearly the entire tumor. Usually, the hypercellular Antoni A region consists of monomorphic spindleshaped Schwann cells with pointed basophilic nuclei and poorly defined eosinophilic cytoplasm. On occasion, however, Verocay bodies, made up of palisading spindle-shaped cells around eosinophilic fibrils, are present in the Antoni A area, as noted in our case (Fig. 3).4,5 Further, secondary changes, such as cystic degeneration, vessels with thick hyaline walls and hemorrhage (Fig. 4), may occur in the Antoni B tissue.1,2,5,8 These secondary changes were also observed in our patient. Rarely, mild nuclear pleomorphism and few normal mitotic figures are identified, especially in the Antoni A area; however, this does not necessarily indicate malignant change.2 Immunohistochemically, negative results for desmin, smooth muscle actin and C-kit protein exclude the possibility of smooth-muscle and stromal tumors.1 Intense S-100 protein immunoreactivity for cytoplasmic and nuclear patterns indicates neural origin.1,6 These staining results and the associated H & E microscopic findings confirmed the diagnosis of schwannoma in the reported case. The involved nerves are frequently of particular interest to the clinicians. For example, the nerves most commonly involved in schwannomas in the parapharyngeal space are the vagus and the cervical sympathetic chain.10 The cutaneous branches of the infraorbital nerve are widely distributed throughout the upper lip, medial portion of the cheek, lower eyelid, and the side of the nose. In the present case, schwannoma of the upper lip may have arisen from a branch of the infraorbital nerve or of cranial nerve V. Asaumi et al6 have reported the findings for
ultrasound, computed tomography, and magnetic resonance imaging for a schwannoma of the upper lip. Homogeneous, hypoechoic features and posterior acoustic enhancement were noted on ultrasound. The computed tomography scan revealed a homogenous softtissue density mass, with a clear margin. By contrast, the magnetic resonance imaging showed a homogenous lesion with low-intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted images. In our case, however, radiologic examination was not arranged because the lesion was relatively small. The prognosis of schwannoma is quite favorable. Conservative surgical removal is the treatment of choice, with wide excision not advocated. If complete enucleation is achieved, no recurrence should be expected.2,5,8,10 Malignant transformation of benign schwannoma has been controversial; some authors are doubtful of its occurrence, although a few isolated cases have been documented.5,8,11 The diagnosis was not considered for our patient because examination of the excised mass revealed benign microscopic features and confirmed complete removal. In summary, schwannoma of the upper lip is a clinical rarity. Complete enucleation usually achieves cure. Malignant transformation of a benign schwannoma remains the major concern. Although very rare, schwannoma should be taken into consideration in the differential diagnosis of an upper lip mass. REFERENCES 1. Thurnher D, Quint C, Pammer J, et al: Dysphagia due to a large schwannoma of the oropharynx: Case report and review of the literature. Arch Otolaryngol Head Neck Surg 128:850-852, 2002
354
2. Bildirici K, Cakli H, Kecik C, et al: Schwannoma (neurilemmoma) of the palatine tonsil. Otolaryngol Head Neck Surg 126:693-694, 2002 3. Das Gupta TK, Brasfield RD, Strong EW, et al: Benign solitary Schwannomas (neurilemomas). Cancer 24:355366, 1969 4. Cherrick HM, Eversole LR: Benign neural sheath neoplasm of the oral cavity. Report of thirty-seven cases. Oral Surg Oral Med Oral Pathol 32:900-909, 1971 5. Barbosa J, Hansen LS: Solitary multilobular schwannoma of the oral cavity. J Oral Med 39:232-235, 1984 6. Asaumi J, Konouchi H, Kishi K: Schwannoma of the upper lip: ultrasound, CT, and MRI findings. J Oral Maxillofac Surg 58:1173-1175, 2000 7. Kara CO, Topuz B: Horner’s syndrome after excision of cervical sympathetic chain schwannoma. Otolaryngo Head Neck Surg 127:127-128, 2002 8. Michida A, Ryoke K, Ishikura S, et al: Multiple schwannomas of the neck, mediastinum, and parapha-
YANG AND LIN
ryngeal space: Report of case. J Oral Maxillofal Surg 53:617-620, 1995 9. Triaridis C, Tsalighopoulos MG, Kouloulas A, et al: Posterior pharyngeal wall schwannoma. J Laryngo Otol 101:749-752, 1987 10. Rosner M, Fisher W, Mulligan L: Cervical sympathetic schwannoma: Case report. Neurosurgery 49:14521454, 2001 11. Shibata Y, Ueda T, Seki H, et al: Gastrointestinal stromal tumour of the rectum. Eur J Gastroenterol Hepatol 13:283-286, 2001 12. Mikami Y, Hidaka T, Akisada T, et al: Malignant peripheral nerve sheath tumor arising in benign ancient schwannoma: A case report with an immunohistochemical study. Pathol Int 50:156-161, 2000 13. Woodruff JM, Selig AM, Crowley K, et al: Schwannoma (Neurilemoma) with malignant transformation. Am J Surg Pathol 18:882-895, 1994