Introduction

Skin cancer is the most common malignancy in the white population, and is related to chronic solar ultraviolet radiation. Although the head and neck comprises only 9% of the total body surface area, most nonmelanoma skin cancers are encountered in this region as a result of sun exposure. The incidence of cutaneous squamous cell carcinoma (SCC) of the head and neck accounts for approximately 20% to 25% of all nonmelanoma skin cancers. Cutaneous SCC of the head and neck rarely metastasizes to regional lymph nodes (approximately 5% of patients), but when it does the parotid lymph node bed is most frequently involved. Patients with metastatic cutaneous SCC have a poor prognosis with an overall 5-year survival rate of 34.4%. Therefore, the detection of macrometastasis or micrometastasis of parotid and/or cervical lymph nodes is crucial. Because the involvement of lymph nodes in cutaneous SCC of the head and neck is relatively uncommon, and as it often takes a long time from the initial tumor identification and treatment to the ultimate development of metastases, it is worthwhile highlighting the disease process to bring it to the forefront of the clinician’s mind. The aim of this article is to review the lymphatic drainage of skin, the principles of lymphatic metastasis, risk factors and patterns of tumor spread, and the staging and therapeutic implications of metastatic cutaneous SCC of the head and neck.