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Monophasic epithelial synovial sarcoma arising in the temporomandibular joint
Int. J. Oral Maxillofac. Surg. 2007; 36: 762–765 doi:10.1016/j.ijom.2007.02.014, available online at http://www.sciencedirect.com
Case Report Head and Neck Oncology
Monophasic epithelial synovial sarcoma arising in the temporomandibular joint
H. A. M. H.
Bukawa, A. Kawabata, Murano, K. Ono, K. Ogawara, Shiiba, H. Yokoe, K. Uzawa, Tanzawa
Division of Dentistry and Oral-Maxillofacial Surgery, Chiba University Hospital, 1-8-1 Inohana, Chuo-ku, Chiba 260-8677, Japan
H. Bukawa, A. Kawabata, A. Murano, K. Ono, K. Ogawara, M. Shiiba, H. Yokoe, K. Uzawa, H. Tanzawa: Monophasic epithelial synovial sarcoma arising in the temporomandibular joint. Int. J. Oral Maxillofac. Surg. 2007; 36: 762–765. # 2007 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Abstract. Synovial sarcoma is a mesenchymal spindle-cell tumour that occurs infrequently in the head and neck. It originates from unknown stem cells differentiating into mesenchymal and/or epithelial structures. Most synovial sarcomas are biphasic in character, consisting of epithelial and spindle-cell elements. Here is reported a case of monophasic epithelial synovial sarcoma arising in the temporomandibular joint. The tumour was of a predominantly epithelial pattern, although a minute area of sarcomatous cells was found. The primary mode of treatment was wide en-bloc excision. Two years after surgery, the patient died of hepatocelluar carcinoma, but there was no evidence of synovial sarcoma recurrence.
Accepted for publication 11 February 2007 Available online 12 April 2007
Synovial sarcoma is the fourth most common type of sarcoma, following malignant fibrous histiosarcoma, liposarcoma and rhabdomyosarcoma9, and accounts for 5–10% of all soft-tissue sarcomas3. Approximately 85% of synovial sarcomas are located in the extremities, with 60% in the lower and 25% in the upper extremities. Nine percent are located on the trunk and the retroperitoneum, whereas only 5% arise in the head and neck region3. Synovial sarcoma is most prevalent in adolescents and young adults between 15 and 40 years of age; 90% of the tumours are found in patients under the age of 50. Males appear to be slightly more susceptible than females, with reported ratios of 1.2:12,8,9.
Head and neck synovial sarcoma was first described in 1954 by Jernstrom, who reported a case of synovial sarcoma of the pharynx2. Since that time, numerous cases of head and neck synovial sarcoma have been reported. The majority of these lesions are located in the prevertebral, parapharyngeal and retropharyngeal spaces from the skull base to the hypopharynx. Fewer are located in the neck, orofacial and laryngeal areas. Occasionally, such tumours are located near articulations, such as the cricoarytenoid, sternoclavicular and temporomandibular (TMJ) joints. Synovial sarcoma arising in the temporomandibular joint was first noted in 1982 by DELBALSO et al.5. Such
0901-5027/080762 + 04 $30.00/0
The first documented synovial sarcoma was described by Simon in 18653, and was thought to involve a synovial membrane because of the tumour’s histological resemblance to synovium. Synovial sarcomas do not in fact originate from mature synovial cells. There are three subtypes: the biphasic type consisting of distinct epithelial and spindle-cell elements, the monophasic fibrous type consisting of only spindle cells, and the poorly differentiated type consisting of poorly differentiated areas of high cellularity, pleomorphism, and polygonal or round-cell morphology, together with frequent mitosis and necrosis.
# 2007 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Synovial sarcoma in the TMJ
763
synovial sarcomas are extremely rare, with only five cases reported in the literature1,4,5,8,9. Here is reported a new case of a synovial sarcoma arising in the TMJ. The histological features are discussed. Case report
A 67-year-old man presented with a painless right preauricular mass that had developed 3 months earlier. He had no history of trauma to his mandible, facial operations, bruxism or clenching habits. He had experienced chronic discomfort and trismus, which reduced spontaneously. The patient’s medical history included tuberculosis, hypertension, cerebral infarction, hepatitis C virus infection and hepatocellular carcinoma. His family history included a father who had cerebral infarction and a mother who had cardiac disease. The patient had experienced chronic and often severe right TMJ pain. He reported no history of weight loss, night sweats, anorexia, malaise or fatigue. On examination, a 40 mm 35 mm, elastic, soft, right preauricular mass was noted. No cranial nerve impairment was present, and he had no trismus on examination. When he opened his mouth, the mandible displaced to the right. Cervical and clavicular adenopathy was absent. A lytic lesion of the right TMJ was revealed by panoramic radiograph (Fig. 1A). A computed tomogram (CT), a 3D CT scan and a magnetic resonance image (MRI) showed severe absorption of the right TMJ and widening of the joint by a mass (Fig. 1B). A chest radiograph and head CT scan revealed no metastatic involvement. On initial examination, the mass was suspected to be malignant. A needle biopsy failed to yield a diagnosis. An open biopsy was performed, which revealed scar tissue, but the mass was considered to be malignant based on the clinical findings, such as severe absorption of TMJ by the mass. It was therefore elected to perform an en-bloc excision. A mandibular ramus resection and functional neck dissection were performed. The mandibular branch of the facial nerve was preserved. The specimen was well circumscribed, 50 mm 42 mm 30 mm in diameter, with a soft, tan, cut surface (Fig. 1C). The mass appeared continuous with the periosteum of the mandibular process. Multinodular and multicystic regions and necrosis were observed. Histologically, the tumour contained only a minute focus of spindle cells and was predominantly composed of epithelial cells with ovoid nuclei and abundant cytoplasm.
Fig. 1. (A) Panoramic radiograph showing a lytic lesion of right TMJ (arrow). (B) MRI shows the tumour mass of the right condyle (arrow); T1-weighted image, coronal view. (C) Operative findings; the resected tumour.
They formed glands with lumina (containing epithelial mucin) or papillary structures. The glandular component predominated with large closely packed glands and a scanty spindle component that could be overlooked, allowing misidentification as adenocarcinoma. Mitoses were scarce (Fig. 2). Immunohistochemical stains revealed that tumour cells were positive for cytokeratins (AE1/AE3, CAM5.2) and epithelial membrane antigen (EMA). Vimentin was demonstrable in the few spindle cells present, but this antigen was absent in the epithelial cells (Fig. 3). The surgical margins were free of tumour and the cervical lymph nodes resected with tumour were negative. No adjuvant chemotherapy was administered because of liver dysfunction. Two years after surgery, the patient succumbed to hepatocellular carcinoma, but there was no evidence of recurrence for synovial sarcoma. Discussion
Synovial sarcoma arising in the TMJ is rare: this is only the sixth case to be
reported in the literature (Table 1). Synovial sarcoma is commonly diagnosed by the biphasic pattern of mesenchymal proliferation and epithelial cells. Theoretically, a pure monophasic epithelial synovial sarcoma exists, but it is often difficult to render this diagnosis with any degree of certainty. The epithelial component is similar to adenocarcinoma, leading to potential misidentification as adenocarcinoma6. Predominantly epithelial forms of synovial sarcoma are diagnosed by identifying small fibrosarcomatous foci3. In fact, most of the tumour resected here contained proliferating epithelial cells, and was initially identified as adenocarcinoma arising from an ectopic salivary gland in the TMJ. Careful observation in many slices found a scanty spindle component in only a minute area, indicating that the tumour was not an adenocarcinoma but a synovial sarcoma. There were transitions between epithelial and spindle cells suggesting a close genetic relationship. Pathological findings also ruled out metastatic hepatocellular carcinoma. Most synovial sarcomas display immu-
764
Bukawa et al.
Fig. 2. Photomicrograph of the predominantly epithelial pattern and only a minute focus of spindle-cell differentiation (haematoxylin and eosin staning, 200). Other portions of this tumour displayed the epithelial pattern characterized by large, round or oval cells, and formed a glandular, cleft-like or cyst-like space. Focal nuclear palisading in a scanty spindle component is present. Transitions between the epithelial and spindle component are seen.
noreactivity for cytokeratins and EMA3. On immunochemical staining, epithelial cells were positive for cytokeratins and EMA, while the spindle cells were positive for vimentin and SMA (smooth muscle actin). These findings suggested that the precursor cells of synovial sarcoma
could arise from pluripotent cells that had not differentiated into epithelial cells or spindle cells. Synovial sarcoma of the TMJ is rare, and cases of monophasic epithelial tumour in this location have not been reported in the literature previously. The case pre-
sented here is the first report of monophasic epithelial synovial sarcoma arising in the TMJ. Table 1 shows six cases of synovial sarcoma arising in the TMJ. All the patients were males. Since in synovial sarcoma males are slightly more susceptible than females in a ratio of 1.2:1, the fact that all patients with synovial sarcoma of the TMJ were males may be one of its characteristics. Wide surgical excision is believed to be essential to treat synovial sarcoma8, and this was performed in all cases (Table 1). Synovial sarcoma is normally radio-resistant in the extremities, but postoperative radiation therapy has been advocated for tumours in the head and neck region7. Large doses in the range of 65 Gy or more are recommended8. The present patient had hepatitis C virus infection with hepatocellular carcinoma, so no radiotherapy was performed to prevent him from developing an immunological disorder. Although the effectiveness of chemotherapy has not been proved, multidrug chemotherapy such as adriamycin and ifosfamide has been used in an attempt to prevent distant metastasis9. Chemotherapy was not performed in the present case due to liver dysfunction. Up to 50% of synovial sarcomas recur, usually within 2 years of surgery, but sometimes up to 30 years after diagnosis. Some 40% of synovial sarcomas metastasize, most commonly to the lungs and bones and also to regional lymph nodes. The 5-year survival rate is 36– 63%, and 10-year survival rate is 16– 46%6,8. Prognosis does not differ between biphasic and monophasic synovial sarcoma6.
Table 1. Cases of synovial sarcoma of the TMJ reported in the literature Case
Reference 5
Gender
Age (years)
Side
Histopathological finding
Treatment
1
DELBALSO et al.
Male
22
Left
Unclear
Surgery Radiation Chemotherapy Surgery Radiation Chemotherapy Surgery Radiation Surgery Radiation Chemotherapy
2
WHITE et al.9
Male
57
Right
Biphasic synovial sarcoma
3
STADELMANN et al.8
Male
49
Left
Biphasic synovial sarcoma
4
CONSTANTINIDIS et al.4
Male
31
Right
Monophasic spindle synovial sarcoma
5
ALLIAS-MONTMAYEUR et al.1
Male
39
Right
Biphasic synovial sarcoma
Surgery
6
Present case
Male
67
Right
Monophasic epithelial synovial sarcoma
Surgery
Progress Unclear Dead 15 months later Alive 9 months later No evidence of recurrence Local recurrence Lung metastasis Bone metastasis Dead 3.5 years later Alive 5 moths later No evidence of recurrence Dead 2 years later from hepatocellular carcinoma No evidence of recurrence
Synovial sarcoma in the TMJ
765
Fig. 3. Immunohistochemical findings (100): (A) epithelial membrane antigen (EMA); (B) AE1/AE3; (C) CAM5.2; (D) smooth muscle actin (SMA); (E) vimentin. Epithelial cells are positive for EMA and cytokeratins (AE1/AE3, CAM5.2), while only a minute number of spindle cells are positive for vimentin and SMA.
Acknowledgements. We are very grateful to Dr. Hirotsugu Yamamoto, Department of Pathology, Nihon University School of Dentistry at Matsudo, and Dr. Jin Kubosawa, Division of Pathology, Chiba Municipal Aoba Hospital for their discussions and suggestions.
4.
5.
References 1. Allias-Montmayeur F, Durroux R, Dodart L, Combelles R. Tumours and pseudotumorous lesions of the temporomandibular joint: a diagnostic challenge. J Laryngol Otol 1997: 111: 776–781. 2. Amble FR, Olsen KD, Nascimento AG, Foote RL. Head and neck synovial cell sarcoma. Otol Head Neck Surg 1992: 107: 631–637. 3. Chang AE, Madewell JE, Rosenberg SA, Moser RP. Synovial sarcoma. In:
6.
7.
Enzinger FM, Weiss SW, eds: Soft Tissue Tumors. St. Louis, MO: C.V. Mosby 1988: 659–688. Constantinidis J, Weber R, Draf W, Kind M, Velegrakis G, Skoulakis CH. Synovialzellsarkome in Kopf-und Halsbereich. Laryngorhinootologie 1995: 74: 98– 102. DelBalso AM, Pyatt RS, Busch RF, Hirokawa R, Fink CS. Synovial cell sarcoma of the temporomandibular joint. Arch Otolaryngol 1982: 108: 520–522. Fisher C, de Bruijin DRH, Geurts van Kessel A. Synovial sarcoma. In: Fletcher CDM, Unni KK, Mertens F, eds: World Health Organization Classification of Tumours, Pathology and Genetics, Tumours of Soft Tissue and Bone. Albany, NY: WHO Publications Center 2000: 200–204. Robinson DL, Destian S, Hinton DR. Synovial sarcoma of the neck: radiographic findings with a review of the lit-
erature. Am J Otholaryngol 1994: 15: 46– 53. 8. Stadelmann WK, Cruse CW, Messina J. Synovial cell sarcoma of the temporomandibular joint. Ann Plast Surg 1995: 35: 664–668. 9. White RD, Markar J, Steckler RM. Synovial sarcoma of the temporomandibular joint. J Oral Maxillofac Surg 1992: 50: 1227–1230. Address: Hiroki Bukawa Division of Dentistry and Oral-Maxillofacial Surgery Chiba University Hospital 1-8-1 Inohana Chuo-ku Chiba 260-8677 Japan Tel: +81 43 226 2300 Fax: +81 43 226 2300 E-mail: [email protected]
Case Report Head and Neck Oncology
Monophasic epithelial synovial sarcoma arising in the temporomandibular joint
H. A. M. H.
Bukawa, A. Kawabata, Murano, K. Ono, K. Ogawara, Shiiba, H. Yokoe, K. Uzawa, Tanzawa
Division of Dentistry and Oral-Maxillofacial Surgery, Chiba University Hospital, 1-8-1 Inohana, Chuo-ku, Chiba 260-8677, Japan
H. Bukawa, A. Kawabata, A. Murano, K. Ono, K. Ogawara, M. Shiiba, H. Yokoe, K. Uzawa, H. Tanzawa: Monophasic epithelial synovial sarcoma arising in the temporomandibular joint. Int. J. Oral Maxillofac. Surg. 2007; 36: 762–765. # 2007 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Abstract. Synovial sarcoma is a mesenchymal spindle-cell tumour that occurs infrequently in the head and neck. It originates from unknown stem cells differentiating into mesenchymal and/or epithelial structures. Most synovial sarcomas are biphasic in character, consisting of epithelial and spindle-cell elements. Here is reported a case of monophasic epithelial synovial sarcoma arising in the temporomandibular joint. The tumour was of a predominantly epithelial pattern, although a minute area of sarcomatous cells was found. The primary mode of treatment was wide en-bloc excision. Two years after surgery, the patient died of hepatocelluar carcinoma, but there was no evidence of synovial sarcoma recurrence.
Accepted for publication 11 February 2007 Available online 12 April 2007
Synovial sarcoma is the fourth most common type of sarcoma, following malignant fibrous histiosarcoma, liposarcoma and rhabdomyosarcoma9, and accounts for 5–10% of all soft-tissue sarcomas3. Approximately 85% of synovial sarcomas are located in the extremities, with 60% in the lower and 25% in the upper extremities. Nine percent are located on the trunk and the retroperitoneum, whereas only 5% arise in the head and neck region3. Synovial sarcoma is most prevalent in adolescents and young adults between 15 and 40 years of age; 90% of the tumours are found in patients under the age of 50. Males appear to be slightly more susceptible than females, with reported ratios of 1.2:12,8,9.
Head and neck synovial sarcoma was first described in 1954 by Jernstrom, who reported a case of synovial sarcoma of the pharynx2. Since that time, numerous cases of head and neck synovial sarcoma have been reported. The majority of these lesions are located in the prevertebral, parapharyngeal and retropharyngeal spaces from the skull base to the hypopharynx. Fewer are located in the neck, orofacial and laryngeal areas. Occasionally, such tumours are located near articulations, such as the cricoarytenoid, sternoclavicular and temporomandibular (TMJ) joints. Synovial sarcoma arising in the temporomandibular joint was first noted in 1982 by DELBALSO et al.5. Such
0901-5027/080762 + 04 $30.00/0
The first documented synovial sarcoma was described by Simon in 18653, and was thought to involve a synovial membrane because of the tumour’s histological resemblance to synovium. Synovial sarcomas do not in fact originate from mature synovial cells. There are three subtypes: the biphasic type consisting of distinct epithelial and spindle-cell elements, the monophasic fibrous type consisting of only spindle cells, and the poorly differentiated type consisting of poorly differentiated areas of high cellularity, pleomorphism, and polygonal or round-cell morphology, together with frequent mitosis and necrosis.
# 2007 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Synovial sarcoma in the TMJ
763
synovial sarcomas are extremely rare, with only five cases reported in the literature1,4,5,8,9. Here is reported a new case of a synovial sarcoma arising in the TMJ. The histological features are discussed. Case report
A 67-year-old man presented with a painless right preauricular mass that had developed 3 months earlier. He had no history of trauma to his mandible, facial operations, bruxism or clenching habits. He had experienced chronic discomfort and trismus, which reduced spontaneously. The patient’s medical history included tuberculosis, hypertension, cerebral infarction, hepatitis C virus infection and hepatocellular carcinoma. His family history included a father who had cerebral infarction and a mother who had cardiac disease. The patient had experienced chronic and often severe right TMJ pain. He reported no history of weight loss, night sweats, anorexia, malaise or fatigue. On examination, a 40 mm 35 mm, elastic, soft, right preauricular mass was noted. No cranial nerve impairment was present, and he had no trismus on examination. When he opened his mouth, the mandible displaced to the right. Cervical and clavicular adenopathy was absent. A lytic lesion of the right TMJ was revealed by panoramic radiograph (Fig. 1A). A computed tomogram (CT), a 3D CT scan and a magnetic resonance image (MRI) showed severe absorption of the right TMJ and widening of the joint by a mass (Fig. 1B). A chest radiograph and head CT scan revealed no metastatic involvement. On initial examination, the mass was suspected to be malignant. A needle biopsy failed to yield a diagnosis. An open biopsy was performed, which revealed scar tissue, but the mass was considered to be malignant based on the clinical findings, such as severe absorption of TMJ by the mass. It was therefore elected to perform an en-bloc excision. A mandibular ramus resection and functional neck dissection were performed. The mandibular branch of the facial nerve was preserved. The specimen was well circumscribed, 50 mm 42 mm 30 mm in diameter, with a soft, tan, cut surface (Fig. 1C). The mass appeared continuous with the periosteum of the mandibular process. Multinodular and multicystic regions and necrosis were observed. Histologically, the tumour contained only a minute focus of spindle cells and was predominantly composed of epithelial cells with ovoid nuclei and abundant cytoplasm.
Fig. 1. (A) Panoramic radiograph showing a lytic lesion of right TMJ (arrow). (B) MRI shows the tumour mass of the right condyle (arrow); T1-weighted image, coronal view. (C) Operative findings; the resected tumour.
They formed glands with lumina (containing epithelial mucin) or papillary structures. The glandular component predominated with large closely packed glands and a scanty spindle component that could be overlooked, allowing misidentification as adenocarcinoma. Mitoses were scarce (Fig. 2). Immunohistochemical stains revealed that tumour cells were positive for cytokeratins (AE1/AE3, CAM5.2) and epithelial membrane antigen (EMA). Vimentin was demonstrable in the few spindle cells present, but this antigen was absent in the epithelial cells (Fig. 3). The surgical margins were free of tumour and the cervical lymph nodes resected with tumour were negative. No adjuvant chemotherapy was administered because of liver dysfunction. Two years after surgery, the patient succumbed to hepatocellular carcinoma, but there was no evidence of recurrence for synovial sarcoma. Discussion
Synovial sarcoma arising in the TMJ is rare: this is only the sixth case to be
reported in the literature (Table 1). Synovial sarcoma is commonly diagnosed by the biphasic pattern of mesenchymal proliferation and epithelial cells. Theoretically, a pure monophasic epithelial synovial sarcoma exists, but it is often difficult to render this diagnosis with any degree of certainty. The epithelial component is similar to adenocarcinoma, leading to potential misidentification as adenocarcinoma6. Predominantly epithelial forms of synovial sarcoma are diagnosed by identifying small fibrosarcomatous foci3. In fact, most of the tumour resected here contained proliferating epithelial cells, and was initially identified as adenocarcinoma arising from an ectopic salivary gland in the TMJ. Careful observation in many slices found a scanty spindle component in only a minute area, indicating that the tumour was not an adenocarcinoma but a synovial sarcoma. There were transitions between epithelial and spindle cells suggesting a close genetic relationship. Pathological findings also ruled out metastatic hepatocellular carcinoma. Most synovial sarcomas display immu-
764
Bukawa et al.
Fig. 2. Photomicrograph of the predominantly epithelial pattern and only a minute focus of spindle-cell differentiation (haematoxylin and eosin staning, 200). Other portions of this tumour displayed the epithelial pattern characterized by large, round or oval cells, and formed a glandular, cleft-like or cyst-like space. Focal nuclear palisading in a scanty spindle component is present. Transitions between the epithelial and spindle component are seen.
noreactivity for cytokeratins and EMA3. On immunochemical staining, epithelial cells were positive for cytokeratins and EMA, while the spindle cells were positive for vimentin and SMA (smooth muscle actin). These findings suggested that the precursor cells of synovial sarcoma
could arise from pluripotent cells that had not differentiated into epithelial cells or spindle cells. Synovial sarcoma of the TMJ is rare, and cases of monophasic epithelial tumour in this location have not been reported in the literature previously. The case pre-
sented here is the first report of monophasic epithelial synovial sarcoma arising in the TMJ. Table 1 shows six cases of synovial sarcoma arising in the TMJ. All the patients were males. Since in synovial sarcoma males are slightly more susceptible than females in a ratio of 1.2:1, the fact that all patients with synovial sarcoma of the TMJ were males may be one of its characteristics. Wide surgical excision is believed to be essential to treat synovial sarcoma8, and this was performed in all cases (Table 1). Synovial sarcoma is normally radio-resistant in the extremities, but postoperative radiation therapy has been advocated for tumours in the head and neck region7. Large doses in the range of 65 Gy or more are recommended8. The present patient had hepatitis C virus infection with hepatocellular carcinoma, so no radiotherapy was performed to prevent him from developing an immunological disorder. Although the effectiveness of chemotherapy has not been proved, multidrug chemotherapy such as adriamycin and ifosfamide has been used in an attempt to prevent distant metastasis9. Chemotherapy was not performed in the present case due to liver dysfunction. Up to 50% of synovial sarcomas recur, usually within 2 years of surgery, but sometimes up to 30 years after diagnosis. Some 40% of synovial sarcomas metastasize, most commonly to the lungs and bones and also to regional lymph nodes. The 5-year survival rate is 36– 63%, and 10-year survival rate is 16– 46%6,8. Prognosis does not differ between biphasic and monophasic synovial sarcoma6.
Table 1. Cases of synovial sarcoma of the TMJ reported in the literature Case
Reference 5
Gender
Age (years)
Side
Histopathological finding
Treatment
1
DELBALSO et al.
Male
22
Left
Unclear
Surgery Radiation Chemotherapy Surgery Radiation Chemotherapy Surgery Radiation Surgery Radiation Chemotherapy
2
WHITE et al.9
Male
57
Right
Biphasic synovial sarcoma
3
STADELMANN et al.8
Male
49
Left
Biphasic synovial sarcoma
4
CONSTANTINIDIS et al.4
Male
31
Right
Monophasic spindle synovial sarcoma
5
ALLIAS-MONTMAYEUR et al.1
Male
39
Right
Biphasic synovial sarcoma
Surgery
6
Present case
Male
67
Right
Monophasic epithelial synovial sarcoma
Surgery
Progress Unclear Dead 15 months later Alive 9 months later No evidence of recurrence Local recurrence Lung metastasis Bone metastasis Dead 3.5 years later Alive 5 moths later No evidence of recurrence Dead 2 years later from hepatocellular carcinoma No evidence of recurrence
Synovial sarcoma in the TMJ
765
Fig. 3. Immunohistochemical findings (100): (A) epithelial membrane antigen (EMA); (B) AE1/AE3; (C) CAM5.2; (D) smooth muscle actin (SMA); (E) vimentin. Epithelial cells are positive for EMA and cytokeratins (AE1/AE3, CAM5.2), while only a minute number of spindle cells are positive for vimentin and SMA.
Acknowledgements. We are very grateful to Dr. Hirotsugu Yamamoto, Department of Pathology, Nihon University School of Dentistry at Matsudo, and Dr. Jin Kubosawa, Division of Pathology, Chiba Municipal Aoba Hospital for their discussions and suggestions.
4.
5.
References 1. Allias-Montmayeur F, Durroux R, Dodart L, Combelles R. Tumours and pseudotumorous lesions of the temporomandibular joint: a diagnostic challenge. J Laryngol Otol 1997: 111: 776–781. 2. Amble FR, Olsen KD, Nascimento AG, Foote RL. Head and neck synovial cell sarcoma. Otol Head Neck Surg 1992: 107: 631–637. 3. Chang AE, Madewell JE, Rosenberg SA, Moser RP. Synovial sarcoma. In:
6.
7.
Enzinger FM, Weiss SW, eds: Soft Tissue Tumors. St. Louis, MO: C.V. Mosby 1988: 659–688. Constantinidis J, Weber R, Draf W, Kind M, Velegrakis G, Skoulakis CH. Synovialzellsarkome in Kopf-und Halsbereich. Laryngorhinootologie 1995: 74: 98– 102. DelBalso AM, Pyatt RS, Busch RF, Hirokawa R, Fink CS. Synovial cell sarcoma of the temporomandibular joint. Arch Otolaryngol 1982: 108: 520–522. Fisher C, de Bruijin DRH, Geurts van Kessel A. Synovial sarcoma. In: Fletcher CDM, Unni KK, Mertens F, eds: World Health Organization Classification of Tumours, Pathology and Genetics, Tumours of Soft Tissue and Bone. Albany, NY: WHO Publications Center 2000: 200–204. Robinson DL, Destian S, Hinton DR. Synovial sarcoma of the neck: radiographic findings with a review of the lit-
erature. Am J Otholaryngol 1994: 15: 46– 53. 8. Stadelmann WK, Cruse CW, Messina J. Synovial cell sarcoma of the temporomandibular joint. Ann Plast Surg 1995: 35: 664–668. 9. White RD, Markar J, Steckler RM. Synovial sarcoma of the temporomandibular joint. J Oral Maxillofac Surg 1992: 50: 1227–1230. Address: Hiroki Bukawa Division of Dentistry and Oral-Maxillofacial Surgery Chiba University Hospital 1-8-1 Inohana Chuo-ku Chiba 260-8677 Japan Tel: +81 43 226 2300 Fax: +81 43 226 2300 E-mail: [email protected]