Head and neck squamous cell carcinoma (HNSCC) is by far the most frequent malignant tumor in this anatomic region. Today, HNSCC is divided into two morphologically, molecularly and clinically fundamentally different entities: conventional and virus-associated (HPV/EBV) neoplasms. Premalignant lesions of nonvirus-associated HNSCC include conventional leukoplakia, dysplasia and proliferative verrucous hyperplasia with an increasing risk for malignant transformation. The morphology of HNSCC comprises a spectrum of growth patterns. In addition, special types of HNSCC must be delineated. Recently, for virus-associated HNSCC, some important clinicopathological specifics have become relevant including a separate staging system for these neoplasms. For non-virus associated HNSCC, new grading procedures have been proposed, which significantly impact on prognosis. These issues will be discussed in this review.
Keywords: Dsyplasia; Human papilloma virus; Leukoplakia; Squamous cell carcinoma; Tumor staging.