Synovial sarcoma of the Temporomandibular joint area: report of a case

Synovial sarcoma of the temporomandibular joint area: report

of a case

Chin-Wan Luo, DDS, MSD,

Chung-Ji Liu, DDS, MSD,

and Kuo-Ming Chang, MD

Taipei, Taiwan

TAIPEI MEDICAL UNIVERSITY HOSPITAL, MACKAY MEMORIAL HOSPITAL, NATIONAL YANG-MING UNIVERSITY, AND MACKAY MEDICINE, NURSING AND MANAGEMENT COLLEGE

Synovial cell sarcoma is a relatively rare tumor of mesenchymal origin. It is a high-grade neoplasm that microscopically shows a monophasic or biphasic cellular pattern and includes epithelial features as well as supporting tissue features. Surgical excision is the primary mode of treatment. Postoperative radiotherapy and chemotherapy also is seen to be helpful. Between 3% and 10% of cases originate in the head and neck. A review of relevant literature shows less than 10 cases of synovial cell sarcoma of the temporomandibular joint area reported in the English literature. We report an additional case of biphasic synovial cell sarcoma arising in the temporomandibular joint area, which caused ear pain, tinnitus, and hearing loss, and we further discuss the clinical features, histopathology,

differential diagnosis, and treatment modality. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;104:e62-e65)

Synovial cell sarcoma is a malignant neoplasm that

arises not from synovial membrane, but rather from

pluripotent mesenchymal cells near or even remote

from the articular surface that is most commonly found

in the extremities.

It comprises 8% to 10% of all soft

tissue sarcoma, and only 3% to 10% of synovial cell

sarcoma occurs in the head and neck.

The most

com-mon sites in the head and neck are the hypopharynx and

retropharynx. It is an extremely rare tumor of the

tem-poromandibular joint area. To our knowledge, there are

only 7 cases of synovial cell sarcoma involving the

temporomandibular joint area reported in the English

literature.

We present an additional case and review

the clinical features of this disease.

CASE REPORT

A 21-year-old woman appeared at the Oral and Maxillofa-cial Surgery Department of Mackay Memorial Hospital with the chief complaint of a tender mass over the right preauric-ular region for approximately 3 years. The discomfort over

the right temporomandibular region was noted for a long time, and the patient paid no attention to it until the mass became progressively larger with increased tenderness. She had visited a local otolaryngologist’s clinic several days be-fore for the ear pain, tinnitus, hearing loss, and mouth opening limitation and was referred to our department. She denied any history of trauma, facial surgery, bruxism, or clenching habits and had not had occlusal appliance therapy or any other form of nonsurgical care. Her medical history was noncontributory except for systemic lupus erythematosus. Physical examina-tion on admission revealed a tender, nonfluctuant mass in the right temporomandibular area about 3 cm in diameter. The skin overlying the swelling was intact without ulceration or induration. The range of mouth opening was limited to about 20 mm.

A computed tomographic scan revealed a focal soft-tissue enhancing tumor near and inferior to the right temporoman-dibular joint area posterior to the condylar neck and ramus of the right mandible. Significant ossification or calcification was seen in the periphery of this lesion. No destruction of the adjacent right mandible was seen (Fig. 1). Panoramic radiog-raphy revealed a well-circumscribed mixed radiolucent-ra-diopaque mass over the posterior border of the mandible, causing a depression in the bone (Fig. 2). There was no evidence of lymphadenopathy.

A fine needle biopsy was performed, which revealed a spindle cell tumor, favoring a benign stromal neoplasm with ossification or with reactive bony formation at the elevated periosteum.

Treatment, including surgical procedure, was discussed with the patient, and she elected to undergo operative exci-sion. The local excision was performed through the preauric-ular incision. The histological examination revealed features of synovial sarcoma with marked osseous metaplasia at the periphery. Microscopically, a biphasic tumor was identified, with predominance of hypercellular fairly uniform hyperchro-matic spindle cells with fibrosarcomalike features, which a_{Attending physician, Division of Oral and Maxillofacial Surgery,}

Department of Dentistry, Taipei Medical University Hospital. b_{Lecturer, Dental School, Taipei Medical University.}

c_{Chief, Department of Oral and Maxillofacial Surgery, Mackay} Me-morial Hospital.

d_{Associate Professor, Dental School, National Yang-Ming} Univer-sity.

e_{Attending physician, Department of Pathology, Mackay Memorial} Hospital.

f_{Department of Pathology, Taipei, Taiwan.}

Received for publication Jan 21, 2007; returned for revision May 9, 2007; accepted for publication May 10, 2007.

1079-2104/$ - see front matter © 2007 Mosby, Inc. All rights reserved. doi:10.1016/j.tripleo.2007.05.009

occasionally contained epithelial-type tumor cells that formed round or slender to irregular glands (Fig. 3, A). Marked ossification forming delicate or compact bony trabeculae was seen in the hard and bony pieces (Fig. 3, B). The ossification was formed abruptly from the spindle cells without apparent osteoid formation like that seen in conventional osteosar-coma, and the term osseous metaplasia was used. The spindle cells were strongly stained for CD99 (Fig. 4, A), whereas the epithelial type of tumor cells and small numbers of spindle cells were positive for cytokeratin antigen 7 (Fig. 4, B) and epithelial membrane antigen (Fig. 4, C). The tumor cells were negative for CD34 or smooth muscle actin.

The postoperative recovery of the patient was uneventful, and all clinical signs subsided. She was discharged 10 days

after the surgical procedure. During this admission, the rou-tine tumor workup was arranged and revealed no evidence of distant metastasis. Adjuvant radiotherapy for 64.5 Gy and chemotherapy with cisplatin, epirubicin, and ifosfamide for 4 courses was completed to prevent distant metastasis and tumor recurrence. The patient has remained free of recurrent tumor 5 years after discharge. A subsequent panoramic ra-diograph revealed that the previous depression of the mandi-ble was remodeling.

DISCUSSION

Synovial cell sarcomas are found in younger patients

between the ages of 15 and 40 years, 90% are younger

than 50 years. Males appear to be slightly more

sus-ceptible than females; the average male to female ratio

is 1.2:1. Synovial sarcomas usually occur in

paraarticu-lar locations of the lower extremities.

The most

soft-tissue enhancing tumor near and inferior to the right temporo-mandibular joint (arrows). Extensive ossification or calcifi-cation is seen in the periphery of this lesion.

Fig. 2. Panoramic radiograph reveals a well-circumscribed, mixed radiolucent-radiopaque mass on the posterior border of the mandible, measuring about 3⫻ 4 cm (arrows).

Fig. 3. Photomicrography. A, Plump spindle cells surround isolated glandlike epithelial component (hematoxylin-eosin, original magnification⫻100). B, Marked ossification forming delicate or compact bony trabeculae is seen in the hard and bony pieces (hematoxylin-eosin, original magnification⫻40). OOOOE

mon sites in the head and neck are the hypopharynx and

the retropharynx. It is an extremely rare tumor of the

temporomandibular joint area. There have been less

than 10 reported cases of synovial sarcoma arising in

the temporomandibular joint area.

The chief complaint of most patients is a

progres-sively enlarging painless mass of several months’

du-ration. In the head and neck region, other findings

include a painful mass, dysphagia, hoarseness, and

dys-pnea, accompanied by some limited range of motion.

The preoperative duration of symptoms is highly

vari-able and is most commonly 2 months to 4 years. A

history of trauma to the involved area does not appear

to be a predisposing factor.

The computed tomographic imaging appearance of

synovial sarcomas of the head and neck has been

de-scribed as multilocular tumor with smooth margins and

heterogeneous enhancement after injection of contrast

medium. It may appear benign in some cases when a

well-demarcated, homogeneous lesion with

calcifica-tion is found in the head and neck.

Findings at surgical removal yield

well-circum-scribed spherical multinodular or lobulated tumors

cov-ered by a thin fibrous membrane or pseudocapsule.

Cystic and hemorrhagic foci are present.

The

his-topathologic findings are the same for synovial

sarco-mas arising in the head and neck and the extremities.

Synovial sarcomas classically show a biphasic cellular

pattern consisting of a stroma of fibroblast spindlelike

cells in which are scattered pale epithelial-like cells

arranged in glandular formations, nests, or cleftlike

spaces. The epithelial-like cells may be cuboidal or

columnar and form papillary projections. Synovial

sar-coma consisting of only 1 cell type, either spindle or

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epithelial, has been described (the monophasic

vari-ant).

Microcalcification has been found in some

cases.

Pathological diagnosis is often difficult. It can

be mistaken for epithelioid sarcoma, fibrosarcoma,

ma-lignant glandular schwannoma, mama-lignant

schwan-noma, clear cell sarcoma, hemangiopericytoma, eccrine

spiradenoma, mesothelioma, pigmented villonodular

synovitis, as well as spindle cell carcinoma and

meta-static carcinoma.

In addition to clinical information,

a number of immunohistochemical stains are available

to facilitate the diagnosis.

Cytogenetic unity is also supported by the

observa-tion that a specific reciprocal chromosomal

transloca-tion t(X;18)(p11.2;q11.2) is found in each form of

synovial sarcoma.

The presence of this translocation

confirms the diagnosis of difficult cases that show

un-usual histological features or are located in unun-usual

sites. Chromosome 18 contains the SYT gene, which

fuses with SSX1 or SSX2 from chromosome X. The

SYT-SSX1 fusion is associated with biphasic variants;

SYT-SSX2 fusion is associated with monophasic

vari-ants.

Wide excision with negative margins remains the

mainstay of therapy. Most metastases are blood borne.

Regional lymph node dissection is not believed to be

necessary unless clinical lymphadenopathy or enlarged

nodes on imaging studies are present.

With local

excision as the only mode of treatment, recurrence rates

as high as 60% to 90% have been reported in the head

and neck region.

Postoperative radiotherapy is

ad-vocated for improved local control rates. Large doses in

the range of 65 Gy or more is considered to be necessary,

but radiotherapy alone is not recommended.

Che-motherapy has been used in an attempt to prevent the

occurrence of distant metastases in advanced disease or

in patients with residual gross tumor.

Metastases are

developing in approximately 50% of patients and are

most often found in the lung. Other favored sites of

tumor metastasis are lymph nodes and bone marrow.

Although not normally a feature of sarcomas,

metasta-sis of regional lymph nodes occurs in 12.5% of cases of

the head and neck and 23% of cases in the extremities.

The prognosis of head and neck synovial sarcoma is

poor; 5-year survival rates range from 36% to 76% and

10-year survival rates range from 11% to 63%.

The

prognosis of head and neck synovial sarcoma is poor;

5-year survival rates range from 36% to 76% and

10-year survival rates range from 11% to 63%

;

overall survival rates for synovial sarcoma are 55%

survival at 5 years and 38% survival at 10 years.

Favorable prognostic factors appear to be early

diag-nosis and the performance of wide surgical excision.

The size of the primary tumor and the depth of invasion

may be the most important prognostic indicators.

Pa-tients whose primary tumor is larger than 4 cm in

diameter have a poorer outcome. Calcifying-type

syno-vial sarcoma has been reported to have a better

prog-nosis.

The authors thank Dr. M.J. Buttrey for her kind review and instructive criticism of this paper.

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Reprint requests:

Chung-Ji. Liu, DDS, MSD

Department of Oral and Maxillofacial Surgery Mackay Memorial Hospital

No 92, Chung-Shan North Road, Sec. 2 Taipei, Taiwan, 10449, Republic of China cjliu@ms2.mmh.org.tw

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