A 60-year-old man presented with malignant fibrous histiocytoma of the oropharynx. The mass extended into the nasopharynx and larynx and caused severe upper airway obstruction that required emergency tracheotomy. Ten years earlier, he had undergone a right partial glossectomy and segmental mandibulectomy for squamous cell carcinoma of the right tongue base, followed by 50 Gy of radiation delivered over 33 sessions. The tumor was so aggressive that changes in its volume were visually distinguishable during physical examination over a 2-week hospital stay. Histologic evaluation revealed 7 mitotic figures per high-power field. Although radiation-induced malignant fibrous histiocytoma is rare in the head and neck, the recent medical literature indicates that its incidence is rising. This rise has been attributed to the increased effectiveness of head and neck cancer therapy, which results in prolonging patients' survival and, hence, their risk of subsequent disease. Because malignant. fibrous histiocytoma is a late complication of radiation therapy, appearing on average 10 years following treatment, it is important that physicians who treat head and neck cancer monitor these patients over the long term and remain alert for its appearance, even despite the apparent "cure" of their original neoplasm.
Stout first described malignant fibrous histiocytoma in 1964 and called it malignant fibrous xanthoma. (1) This aggressive, high-grade sarcoma is most commonly found in adults. (2) Ionizing radiation, which is an important modality of treatment for head and neck cancers such as squamous cell carcinomas, has been identified as a factor in the transformation of soft-tissue cells to malignant fibrous histiocytoma. (3) This tumor arises most often in the soft tissues of the extremities and retroperitoneum; it has been considered rare in the head and neck. (4) In 1989, the cumulative incidence of sarcoma following radiation therapy was reported to range from 0.03 to 0.3%. (5) However, an analysis published in 1998 reported a higher incidence of 1 to 3%. (6) This rise in incidence is likely attributable to the increased effectiveness of cancer therapy, which prolongs survival and increases the risk of eventual postradiation cancer. (7) Therefore, it is important that surgeons who treat head and neck cancer be cognizant of this long-term postradiation complication and to continue to follow these patients indefinitely.
A 60-year-old man presented with a 1-month history of progressively worsening dysphonia and dyspnea, which required an emergency tracheotomy to establish an airway. Ten years earlier, he had undergone a right partial glossectomy and segmental mandibulectomy for squamous cell carcinoma of the right tongue base, followed by 50 Gy of radiation delivered over 33 sessions at another institution.
Computed tomography (CT) of the neck revealed that a bulky tumor extended from the nasopharynx to the level of the true vocal folds--predominately on left side, but crossing the midline. The tumor involved the right tongue base, and it displaced and filled the left pyriform sinus and vallecula (figure 1).
[FIGURE 1 OMITTED]
Flexible laryngoscopy revealed that the mass occupied the nasopharynx, and direct laryngoscopy under general anesthesia following tracheotomy detected a left tongue-base tumor with a diameter of at least 5 cm in the supraglottic region. The left neck mass measured 3 cm in diameter. Histologic evaluation revealed a moderately cellular spindle-cell neoplasm and marked cytologic atypia with multinucleated giant cells and a high mitotic figure of 7 per high power field (figure 2). Necrosis was present. Stains for S-100 protein, desmin, CD117, factor VIII, smooth-muscle actin, CD34, and ALK-1 were negative. Staining was faintly positive for Myo-D1 and strongly positive for CD68. The final pathologic diagnosis was malignant fibrous histiocytoma.
[FIGURE 2 OMITTED]
The patient and his family declined further treatment. During routine daily physical examinations over a 2-week hospital stay, a substantial increase in the volume of the oral mass could be seen, which illustrates the aggressive nature and rapid growth of malignant fibrous histiocytoma. The patient died approximately 2 months later.
Malignant fibrous histiocytoma is a subtype of sarcoma that originates in fibroblasts; it is the most common radiation-induced sarcoma of the head and neck, and it accounts for approximately 5% of all head and neck sarcomas. (7) Factors associated with a poor prognosis are tumor size larger than 3 cm, high-grade histology, advanced age, and male sex (6,8):
* Tumors larger than 3 cm are associated with a 42% mortality rate, while the mortality rate for smaller tumors has been reported to be only 18%. (6)
* The 5-year survival rate is 32% for patients with high-grade histology, compared with 81% for those with low-grade histology. (6)
* The mortality rate among patients older than 60 years is 72%, compared with 33% for patients aged 20 to 39 years. (6)
Approximately 30% of all cases of malignant fibrous histiocytoma of the head and neck involve the sinonasal tract; 15 to 20% involve the craniofacial region; 10 to 15% involve the soft tissue of the neck, the major salivary glands, and the larynx; and 5 to 15 % involve the oral cavity. (9)
Four criteria must be met before a malignant fibrous histiocytoma can be diagnosed as a radiation-induced tumor (10,11):
* a documented history of irradiation
* a latency period longer than 5 years
* a different histology in the new tumor in cases when radiation was administered for a malignancy
* the presence of a histologically proven malignancy arising within the irradiated field
Wide radical surgical excision is the treatment of choice for malignant fibrous histiocytoma. When regional lymph nodes are involved, neck dissection is warranted. Doxorubicin is the only chemotherapeutic agent known to exhibit some efficacy against malignant fibrous histiocytoma. Radiation therapy is not very effective, but it has been used for unresectable tumors and in patients who have positive margins after surgical resection. (12)
In conclusion, advances in the treatment of head and neck malignancies have led to better survival rates among affected patients. Moreover, radiation therapy has been used widely during the past 20 to 30 years for treating low-stage head and neck cancers. Therefore, the rise in the incidence of radiation-induced malignancies such as malignant fibrous histiocytoma should not be surprising. Physicians who treat head and neck cancers should be cognizant of the occurrence of radiation-induced tumors, and long-term follow-up is advisable so that such tumors can be detected early.
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(7.) Patel SG, See AC, Williamson PA, et al. Radiation induced sarcoma of the head and neck. Head Neck 1999;21:346-54.
(8.) Haberal I, Samim E, Astarci M, Ozeri C. Radiation-induced malignant fibrous histiocytoma of the neck in a patient with laryngeal carcinoma. Am J Otolaryngol 2001;22:146-9.
(9.) Singh B, Shaha A, Har-El G. Malignant fibrous histiocytoma of the head and neck. J Craniomaxillofac Surg 1993;21:262-5.
(10.) Cahan WG, Woodard HQ, Higinbotham NL, et al. Sarcoma arising in irradiated bone: Report of eleven cases. 1948. Cancer 1998;82:8-34.
(11.) Bradley PJ. Radiation induced tumors of the head and neck. Current Opinion in Otolaryngology Head and Neck Surgery 2002;10:97-103.
(12.) Blitzer A, Lawson W, Zak FG, et al. Clinical pathological determinants in prognosis of fibrous histiocytomas of head and neck. Laryngoscope 1981;91:2053-70
From the Department of Otolaryngology Head and Neck Surgery, Philadelphia College of Osteopathic Medicine (Dr. Sadati); the Department of Pathology, Graduate Hospital, Philadelphia (Dr. Haber); and the Department of Otolaryngology-Head and Neck Surgery, Thomas Jefferson University, Philadelphia (Dr. Sataloff).
Reprint requests: Robert T. Sataloff, MD, Professor of Otolaryngology-Head and Neck Surgery, Thomas Jefferson University, 1721 Pine St., Philadelphia. PA 19103. Phone: (215) 545-3322; fax: (215) 790-1192; e-mail: RTSataloff@phillyent.com
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