[Mode of spread in nasopharyngeal carcinoma as seen on CT scan]

From April 1984 to April 1986, 993 NPC patients were scanned with an 8800 CT scanner in our hospital. 200 consecutive cases who had CT scan before treatment were selected for analysis. CT features of local invasion, incidence of involvement of the parapharyngeal spaces and the adjacent structures, and bone destruction of the base of the skull were analysed. The results showed that the mode of local spread of nasopharyngeal carcinoma is direct infiltration. It tends to spread posterolaterally. According to the relation of the carotid sheath area and lymph nodes in the neck, it is most likely that metastasis in the cervical lymph nodes is the result of direct spread of the disease via the carotid sheath area. CT could detect more bone destruction of the skull base than the conventional submental view. The relationship of neck lymph node metastasis and bone destruction is discussed.