Radiation-induced sarcoma of the base of the tongue.

A 61-year-old man presented with a 1-month history of dysphagia and odynophagia. He had a history of squamous cell carcinoma of the larynx that had been treated with a total laryngectomy and radiation therapy 5 years earlier.

Examination of the oral cavity revealed the presence of a large pedunculated mass on the base of the tongue; findings on the remainder of the head and neck examination were unremarkable. Magnetic resonance imaging (MRI) of the neck demonstrated a 4.5 x 2.4 x 3.0-cm mass at the base of the tongue (figure 1). Analysis of an incisional biopsy specimen led to a diagnosis of malignant fibrous histiocytoma.

[FIGURE 1 OMITTED]

The patient underwent surgical excision of the mass via a midline mandibulotomy, which allowed for good access to the tongue base. A transcervical approach would have been undesirable because the patient had exhibited significant postsurgical and postradiation fibrosis. A cervical approach might also have resulted in an inadvertent entry into the neopharynx.

During surgery, no incisions of the floor of the mouth were required because the mandibulotomy provided such excellent exposure of the tongue base (figure 2). All tumor margins were negative for disease. The patient recovered uneventfully, and at the 1-year follow-up, he exhibited no evidence of recurrence.

[FIGURE 2 OMITTED]

After a disease-free period of 5 years, patients with primary squamous cell carcinoma of the head and neck are generally considered to be cured of their local disease. However, those who have undergone radiation have a higher risk of developing other primary tumors. The tumor in our patient was determined to be a radiation-induced mass because it met three criteria for such a diagnosis: (1) radiation had been previously delivered to the site of the new malignancy, (2) the new tumor was histologically distinct from the original primary lesion, and (3) the latent period between the time of radiation exposure and the development of the new malignancy was 5 years or longer. (1)

Radiation-induced tumors are rare; the reported overall incidence ranges from 0.03 to 0.3%. (2) Sarcomas account for 12% of postradiation neoplasms. (2) They usually arise from the margins of the radiation field. Head and neck lesions account for 13 to 16% of radiation-induced sarcomas. (2) Malignant fibrous histiocytoma is the most common radiation-induced soft-tissue sarcoma, followed by rhabdomyosarcoma, angiosarcoma, fibrosarcoma, chondrosarcoma, and leiomyosarcoma.

Surgery is the primary treatment; chemotherapy is reserved for patients with unresectable disease and for those with positive tumor margins. Five-year disease-free survival rates range from 10 to 30%. (2) Although midline mandibulotomy is considered an aggressive approach, it affords excellent surgical exposure, allows for complete tumor resection, and provides an alternate route of access in an extremely "woody" neck.

References

(1.) Coia LR, Fazekas JT, Kramer S. Postirradiation sarcoma of the head and neck: Areport of three late sarcomas following therapeutic irradiation for primary malignancies of the paranasal sinus, nasal cavity, and larynx. Cancer 1980;46:1982-5.

(2.) Patel SR. Radiation-induced sarcoma. Curt Treat Options Oncol 2000;1:258-61.

From the Department of Otolaryngology, Charles R. Drew University of Medicine and Science, Los Angeles (Dr. Hamilton, Dr. Avitia, Dr. Osborne, and Dr. Brown), and the Head and Neck Cancer Center, Cedars-Sinai Medical Center, Los Angeles (Dr. Osborne).