Oropharyngeal squamous cell carcinoma metastatic to lower-extremity soft tissues: a case report and literature review.

A 52-year old man was referred to our service for evaluation after being diagnosed with oropharyngeal squamous cell carcinoma. Contrast-enhanced computed tomography (CT) revealed a mass in the left tonsillar pillar, as well as submental lymphadenopathy. The extent of tumor infiltration was assessed by fluoro-2-deoxyglucose positron emission tomography scans, which showed increased uptake in the tumor bed and a suspicious-looking lymph node near the right hilum. No other signs or symptoms of distant metastasis were evident at that time, and the patient was treated with induction chemotherapy followed by chemoradiation. Several weeks after treatment completion, the patient returned, complaining of right medial foot edema. CT of the right lower extremity revealed multiple high-attenuation masses in the soft tissues of the right leg and foot, including a mass in the medial plantar region of the foot. Approximately 15 to 20% of patients with oropharyngeal squamous cell carcinoma develop distant metastasis throughout the course of the disease. Soft-tissue metastases from oropharyngeal cancers are rare, however, particularly when they present in the absence of widespread metastasis. A review of the current head and neck tumor literature describes soft-tissue metastases in less than 10% of patients with known distant metastases. Metastasis to distal regions such as the lower extremities has rarely been observed but should be included in the differential diagnosis for patients presenting with lower-extremity pain or edema.