Squamous Cell Carcinoma and Its Variants.

Abstract

Squamous cell carcinoma (SCC) is one of the most common malignant neoplasms involving the anterior skull base, resulting from local invasion from an adjacent anatomical region. The primary sites of origin are most frequently the nasal cavity and paranasal sinuses, and less often the skin and orbit. Treatment strategies for these tumors have evolved, although management remains challenging due to the proximity to critical structures and their location at the intracranial-extracranial interface. The rarity of these tumors, and limited numbers at any one institution, has meant that most published series have grouped together different histologies in reporting outcomes. Data on SCC alone are thus limited. Treatment of SCC involving the anterior skull involves a multidisciplinary team approach. A number of potential treatment options exist, dependent on tumor, patient, and institutional factors. Current treatment strategies commonly involve multimodality therapy using a combination of surgery, radiotherapy, and chemotherapy. Primary surgery is considered the mainstay of initial treatment in those tumors which are deemed resectable, followed by adjuvant radiotherapy with or without chemotherapy. Preoperative assessment includes confirmation of the tissue diagnosis, and imaging to assess resectability, guide the surgical approach, and to plan the extent of surgery and method of reconstruction. Analysis of our institutional database for patients undergoing surgery with SCC involving the anterior skull base showed a 5-year disease-specific survival of 65% for sinonasal SCC and 71% for cutaneous SCC. The surgical margin status as well as dural and pterygopalatine fossa involvement were predictors of a poor prognosis.