Etiopathogenesis/Causative Factors

Approximately 9% of soft tissue sarcomas in adults originate in the head and neck, whereas most arise in an extremity (59%), the trunk (19%), or the retroperitoneum (15%). Like sarcoma in general, head and neck sarcoma occurs in a wide range of age groups, though most often in children, adolescents, and young adults. Indeed, in children, as many as 35% of rhabdomyosarcomas arise in the head and neck. Sarcomas are very rare among head and neck neoplasms, representing only 1% of all primary tumors located within the head and neck region. The majority of head and neck sarcomas arise sporadically in patients without identifiable predisposing genetic risk factors, and exposure to a known environmental carcinogen can be identified in less than 10% of patients with head and neck sarcomas.

Pathologic Anatomy

Considering the preponderance of benign soft tissue masses and the relative frequency of cervical metastases from squamous cell carcinoma of the upper aerodigestive tract, a diagnosis of sarcoma is rare in the head and neck. Moreover, the nonspecific nature of presenting symptoms, sometimes brought to attention by antecedent trauma, typically fails to raise the suspicion of sarcoma, resulting in delay in diagnosis. Together, these factors contribute to the difficulty in diagnosing sarcoma at most head and neck sites. A minority of patients develop tumors at subsites that produce symptoms early and allow earlier detection. The subsite of origin determines the clinical presentation and subsequent diagnostic evaluation of patients with sarcoma of the head and neck.

Among 1161 patients evaluated with sarcoma of the head and neck at the University of Texas M. D. Anderson Cancer Center between 1970 and 2004 ( Table 58-1 ), the most frequent subsites of origin included the scalp or face (30%) and the sinonasal tract or anteromedial skull base (31%). The parotid gland or neck accounted for 19% of these tumors and the upper aerodigestive tract (oral cavity, oro/hypopharynx, and larynx) for 18%; sarcomas arising from the ear or posterolateral skull base were exceedingly rare (only 1%).

Like soft tissue sarcomas of the extremity and trunk, those arising in the neck commonly present as a painless mass. Although a frequent presentation of head and neck sarcoma, a solitary neck mass is only rarely diagnosed as a primary soft tissue sarcoma. Although the presentation of a patient with a painless neck mass raises a broad range of diagnostic possibilities, the clinical setting alone can often narrow the differential diagnosis. Tumors of the neck can impinge on vital structures, causing dysphagia, hoarseness, and even dyspnea. Physical examination typically reveals a subcutaneous mass with possible distortion or destruction of adjacent structures. Associated signs and symptoms of pain and fixation to deep structures are ominous. Like painless masses arising in the neck, those in the parotid region do not frequently raise suspicion of sarcoma on differential diagnosis. Sarcoma of the scalp and face may present with skin and soft tissue manifestations that suggest the pathologic type. For instance, erythematous or violaceous macular lesions, which are often described as a spreading bruise, suggest angiosarcoma, whereas a raised, sclerotic, reddish blue plaquelike nodule is associated with dermatofibrosarcoma protuberans.

Pathologic Anatomy

Considering the preponderance of benign soft tissue masses and the relative frequency of cervical metastases from squamous cell carcinoma of the upper aerodigestive tract, a diagnosis of sarcoma is rare in the head and neck. Moreover, the nonspecific nature of presenting symptoms, sometimes brought to attention by antecedent trauma, typically fails to raise the suspicion of sarcoma, resulting in delay in diagnosis. Together, these factors contribute to the difficulty in diagnosing sarcoma at most head and neck sites. A minority of patients develop tumors at subsites that produce symptoms early and allow earlier detection. The subsite of origin determines the clinical presentation and subsequent diagnostic evaluation of patients with sarcoma of the head and neck.

Among 1161 patients evaluated with sarcoma of the head and neck at the University of Texas M. D. Anderson Cancer Center between 1970 and 2004 ( Table 58-1 ), the most frequent subsites of origin included the scalp or face (30%) and the sinonasal tract or anteromedial skull base (31%). The parotid gland or neck accounted for 19% of these tumors and the upper aerodigestive tract (oral cavity, oro/hypopharynx, and larynx) for 18%; sarcomas arising from the ear or posterolateral skull base were exceedingly rare (only 1%).