Male patient, 28 years old, attended our Service, for an evaluation and treatment of a laterocervical tumor-like mass on the right side that had been evolving for four years. It was painful on palpation and did not exhibit progressive growth. He did not have any previous medical or surgical history.

On examination, a laterocervical mass could be appreciated on the right side, in the middle part of the neck, measuring 2.5 cm in greatest diameter, and which was hard in consistency. It was attached to the hyoid bone and moved on swallowing. Cervical adenopathies were not felt on palpation. The initial clinical opinion was of a thyroglossal cyst.

Blood tests, ultrasound, Fine- Needle Aspiration Puncture (FNAP) and a Computerized Axial Tomography (CAT) scan were requested. The blood tests showed no irregularities. The result of the ultrasound showed a cystic mass, which was compatible with a thyroglossal cyst. The CAT scan showed a heterogeneous mass (Fig. 1). The diagnosis from the FNAP was of a: mesenchymal tumor.

Later, in order to eliminate the existence of any ectopic thyroid tissue, a gamma scan was carried out with radioisotope that did not show any increase in up-take in the area of the mass, nor any disturbances in thyroid up-take.

A month after the first consultation, with a presumed diagnosis of «thyroglossal cyst», a resection was carried out. During the dissection the mass ruptured, and the granular content of the tumor ran out, and this was used to carry out an intraoperative anatomopathologic study. The result was: undifferentiated malignant tumor. The resection of the tumor was then carried out leaving safety margins that included the muscle around the tumor and the central portion of the hyoid body.

Macroscopically the sections showed a whitish mass that was homogenous with brownish areas of a hematic appearance in which a calcified and lumpy area could be identified.

The anatomopathologists reported, following hematoxylin and eosin staining, that the mass consisted of a neoformation of densely packed cells, that was moderately atypical and that had a high mitotic index. It had a solid, fusocellular pattern with vascular areas of a hemangiopericytoma type. The immunohistochemical results were: focally positive for cytokeratin; diffusely strongly positive for vimentin (Fig. 2); and negative for S-100, actin, desmin, enolase, chromogranins, and HMB45.

J.A. García de Marcos¹, A. Dean Ferrer², F. Alamillos Granados², J.J. Ruiz Masera², 
G. Barrios Sánchez¹, A. Vidal Jiménez³

1 Médico Residente, Cirugía Oral y Maxilofacial.
2 Especialista en Cirugía Oral y Maxilofacial.
3 Médico Residente, Anatomía Patológica.
Servicio de Anatomía Patológica.
Hospital Universitario «Reina Sofía». Córdoba, España.

Correspondencia:
J.A. García de Marcos
C/ Antonio Acuña, 10, 5ºA izq
28009 Madrid, España.
E-mail: pepio2@hotmail.com

The diagnosis was of monophasic spindle cell synovial sarcoma.

The patient was then referred to the Medical Oncology and Radiotherapeutic Oncology Services where he was given adjuvant chemotherapy treatment with epirubicine and ifosfamide every three weeks and for six cycles. He later received radiotherapy treatment to the neck of 66 Gy. Two years and three months after the first surgery, the patient presented with a new nodule that was located at the level of the parahyoid bone on the left side, and which was growing progressively (Fig. 3). After carrying out a CT scan, a solid mass could be seen that was heterogeneous and that measured 5 x 5 cm in greatest diameter. It was situated between the thyroid cartilage, the sternocleidomastoid muscle and the thyroid gland on the left side of the neck (Fig. 4). No other lesions were found around the neck or lungs or in the mediastinum. The patient was reoperated and an excision was carried out of the tumor that included the prelaryngeal muscle group and the omohyoid muscle (Fig. 5). The anatomopathologic diagnosis of the sample was of: poorly differentiated sarcoma compatible with synovial sarcoma.

The Medical Oncology Service treated the patient again and he was given adjuvant chemotherapy, which consisted of four cycles with a similar regimen as the previous one, until completing the dose of antracycline.

During a CAT scan check of the neck and lungs, two nodules appeared in the lungs. These were removed 10 months after the second surgery. The anatomopathological result was of lung metastasis of poorly differentiated sarcoma, compatible with monophasic synovial sarcoma.

A year and a half after the first local relapse the patient had a new cervical relapse. In the CAT scan a mass on the left side of the neck could be appreciated that was in contact with the infrahyoid muscles and with the plates of the thyroid cartilage on this side (Fig. 6). Surgical intervention was carried out and the lesion, the adjacent muscles and the left half of the hyoid bone were resected. The tumor was released from the left side of the thyroid cartilage, and a peripheral chondrectomy of thyroid cartilage was performed. The histopathological result was of: monophasic synovial sarcoma. He was later given three cycles of chemotherapy with etoposide and ifosfamide. In the year following the last intervention there have been no signs of relapse.

Discussion

Synovial Sarcomas account for 3-10% of all sarcomas. Generally young adults are affected, two thirds of whom are under the age of 40. Men are more frequently affected than women with a 2:1 or 3:1 rate.^1,2

In spite of its name, these tumors do not originate from synovial tissue, rather they arise from pluripotential mesenchymal cells situated by, as well as away from, joint surfaces.³ As a result, this type of tumor rarely appears in synovial membranes with only 10% affecting joint spaces. It is found more often in the area of large joints and sacs, in or near tendons and tendon sheaths, and fascial aponeuroses. ^2,4

In 75 to 95% of occasions synovial sarcomas are located in the extremities with the lower extremities being more frequently involved. The most common sites of origin are around the hip, knee, ankle, shoulder and wrist joints. It may also appear in the pelvis, the head and the neck, and in areas that do not have synovial tissue such as the abdominal wall.²

Between 3 and 10% of synovial sarcomas appear in the head and neck.^2,4,5 Jernstrom described the first case with this location in 1954 and it entailed a hypopharyngeal tumor.^1-4

Patients with synovial sarcomas of head and neck have a mean age of 25 to 30 and the age range is 7 to 63 years. Gender distribution is the same as in the rest of the economy. ¹

In the head and neck it is the hypopharynx that is the area most affected. Other locations of the head and neck that have been described in the literature include the parapharyngeal space, oral cavity, tongue, parotid gland, temporomandibular joint, the area of the nasal sinuses, nasopharynx and oropharynx, etc. although virtually any area may be affected. ^1-4

The size of these tumors can vary when diagnosed from 1 to 12 cm, the mean size being 5 cm.¹ Generally these are firm, solitary tumors with a shiny cut surface, well-circumscribed, either spherical or micronodular with a pseudocapsule and a yellowish- gray shiny color. There is frequently focal calcification and there can be cystic or hemorrhaging areas (such as in the case we present).

Although metastasis largely takes place through the blood stream, 10 to 20% of patients develop lymphatic metastasis. Lung metastasis occurs generally during the first two years following the diagnosis of the primary tumor.⁶

Clinically, synovial sarcomas of the head and neck tend to appear as slow-growing painless masses. Only in 20% of cases does pain appear.^1,6 Generally dyspnea, dysphagia and hoarseness arise due to the pressure of the tumor on the hypopharynx and larynx. Most patients seek medical attention during the first year, at the onset of symptoms.

Most synovial sarcomas can appear clinically to be a fibrosarcoma or a rhabdomyosarcoma, as they behave as a mass that infiltrates soft-tissues.²

A differential diagnosis has to given with neck masses and, as young patients are involved, thyroglossal cysts, branchial cleft cysts and specific adenopathies (tuberculosis, sarcoidosis, etc.) have to be considered, and also tumors of mesenchymal origin, those originating in the salivary glands, lymph node metastasis and lymphomas.

In CAT and the Nuclear Magnetic Resonance (NMR) imaging, the lesion is described in the head and neck as generally being well-defined, solid, and on occasions as having a hemorrhagic or cystic component as well as calcifications. ^2-4 The images from the CAT scan as well as from the NMR should include all the neck, because in 12.5% of patients with synovial sarcoma of the head and neck there is regional lymph node involvement.^4,6 A CAT scan of the thorax should also be carried out in order to detect the existence of lung metastasis, which is the cause of death in a significant number of patients.⁶ Synovial sarcomas are histologically characterized by the presence of a biphasic pattern consisting of a stromal background made up of spindle cells that appear to be tightly compacted fibroblasts with a relatively monotonous appearance. The epithelial component is set out against this background usually exhibiting a glandular formation, compact nests, or cleft-like spaces.7 The fusocellular areas remind one of the histology of the fibrosarcoma.^1,2 These synovial sarcomas can be highly vascular and they may appear histologically as hemangiopericytomas. The relative proportion of spindle cells to epithelial cells varies from case to case and within the lesion itself.

There are monophasic forms of synovial sarcoma that only have a fusocellular or epithelial histological pattern.^1,4 Metastasis of the biphasic type can have a monophasic or biphasic pattern, while metastasis of the monophasic type is always monophasic.¹

Cytogenetic studies have been carried out of synovial sarcomas that have shown a reciprocal translocation between chromosome X and 18 in more than 90% of cases, in biphasic as well as monophasic cases (p11.2;q11.2)^1,2,4,7 Most cases of synovial sarcoma are diploid.¹

Immunohistological techniques have demonstrated that spindle cells, and epithelial cells to a lesser degree, are stained by vimentin, which is a mesenchymal marker. The reactivity to cytokeratin and to epthithelial membrane antigen is not only found in patterns with an epithelial component but also in a small percentage of cells, in the monophasic patterns of spindle cells. Some synovial sarcomas express S-100 protein.^1,7

The treatment for synovial sarcoma is surgical.¹ Excision with security margins should be carried out, and should often include adjacent tissue, such as the muscles around the tumor.⁴ Routine radical dissection of the neck is not considered necessary if there are no adenopathies.¹ The recurrence rate of synovial sarcomas of the head and neck, after local excision, varies between 21 and 56%, and postoperative radiotherapy is therefore indicated.^1,4,6 Adjuvant chemotherapy can reduce or delay the appearance of distant metastasis.^1,4

Generally sarcomas have a prolonged evolution, and metastasis can develop in some patients up to 20 years after the initial therapy. The average survival rate is approximately 5 to 6 years, with long periods of survival being possible, even when metastasis exists. The survival rate for synovial sarcoma of the head and neck at five years is 36 to 54% and at 10 years it is 20% due to the appearance of metastatis.^1,4

The prognosis of synovial sarcoma is determined by a series of factors: histologically calcified synovial sarcoma carry a better prognosis than the rest;^1,4 depending its greatest diameter and extension, tumors measuring less than 5 cm that are not invading adjacent structures carry a better prognosis; according to the location, the prognosis in the head and neck is better than in the extremities,⁴ with the tongue carrying the best prognosis;¹ according to the Ki-67 index, when this is greater than 10% the prognosis is worse.⁵

References

1. Kiriakos M, El-Mofty S. Pathology of selected soft-tissue tumors of the head and neck. En: Thawley SE, Panje WR, Batsakis JG, Lindberg RD. Comprehensive Management of Head and Neck Tumors. 2ª Ed. Philadelphia. W.B.Saunders Company 1999;Cap. 63. pp.1349-51.        [ Links ]

2. Malignant Soft Tissue Tumors of Mesenchimal Origin. En: Marx RE, Stern D. Oral and Maxillofacial Pathology. A Rationale for Diagnosis and Treatment. Illinois. Quintessence Publishing Co, Inc 2003; Cap. 10. pp.495-6.        [ Links ]

3. Park JK, Ham SY, Hwang JC, Jeong YK, Lee JH, Yang SO, Suh JH, Choi DH. Synovial sarcoma of the head and neck: A case of predominantly cystic mass. Am J Neuroradiol 2004;25:1103-5.        [ Links ]

4. Rangheard AS, Vanel D, Viala J, Schwaab G, Casiraghi O, Sigal R. Synovial sarcomas of the head and neck: CT and MR imaging findings of eight patients. Am J Neuroradiol 2001;22:851-7.        [ Links ]

5. Bilgic B, Mete O, Öztürk AS, Demiryont M, Keles N, Basaran M. Synovial sarcoma: a rare tumor of larynx. Pathol Oncol Res 2003; 9: 242-5.        [ Links ]

6. Cotton RT, Rothschild MA, Zwendling T, Ballard ET, Myer CM, Koch B. Tumors of the head and neck in children. En: Thawley SE, Panje WR, Batsakis JG, Lindberg RD. Comprehensive management of head and neck tumors. 2ª Ed. Philadelphia. W.B.Saunders Company 1999; Cap 81. pp.1857-8.        [ Links ]

7. Rosai J. Soft Tissues. En: Juan Rosai. Rosai and Ackerman´s Surgical Pathology. 9ª Ed. China. Mosby 2004; Cap 25. pp.2309-13.        [ Links ]