A propopsal concerning the histological typing of primary nasopharyngeal carcinoma

Abstract

A proposal concerning the histological typing of primary nasopharyngeal carcinoma is offered in order to coincide with pathologic terms used both by Chinese and foreign pathologists and reflect the achievements in the research field of NPC. This proposal was worked out mainly basing upon the authors’ diagnostic experience gained in the past 30 years and the international criteria for tumor classification. Primary nasopharyngeal carcinoma could be classified into four major types, namely, keratinizing squamous cell carcinoma (KSCC), non- keratinizing carcinoma (NKC), adenocarcinoma (AC) and carcinomain-situ (CIS). KSCC could be graded as being well, moderately and poorly differentiated according to the amount of keratinization and intercellular bridges presented in the biopsy slide. The NKC is the most frequent type seen in the high-incidence area of NPC, and could also be subdivided into differentiated and undifferentiated variants. Actually, three grades of KSCC and two variants of NKC are a reflection of different degrees of squamous differentiation. They are consistently associated with Epstein-Barr virus (EBV) infection. There are two major categories of nasopharyngeal AC, namely, traditional and salivary-gland type. As contrasted with KSCC and NKC, nasopharyngeal AC is rarely infected with EBV. There are two subtypes of CIS, namely, squamous- and columnar-cell type. The histological typing concerning the primary nasopharyngeal carcinoma offered above is really a practical proposal and also coincided with the international usage. This proposal can be mastered easily and the authors recommend its routine use in diagnostic pathology.