RESUMEN
<p><b>OBJECTIVE</b>To investigate the prevalent area where the nasopharyngeal carcinoma (NPC) initially would develop most frequently in the nasopharynx.</p><p><b>METHODS</b>From March, 1994 to June, 2003, the data of original micro-focus of 32 pathologically confirmed NPC were retrospectively reviewed, All cases were shown by CT to have stages T(0) or T(1) lesions.</p><p><b>RESULTS</b>On clinical examination, only 3 cases (9.4%) were found to have original micro-tumor in the recess, the other 29 cases (90.6%) had developed from the other regions including 20 (69.0%) from the roof and 9 cases (31.0%) from the posterior wall, all with the mucosa in the recess smooth and symmetrical. However, CT images showed that membrane of all the nasopharyngeal walls, including the recess, were normal in 24 cases (75.0%); except the micro-foci were observed on one side of the posterior wall in 5 cases (15.6%) but still with the recess normal, One lateral wall and/or the recess were involved with abnormal appearance in 3 cases (9.4%) who were clinically found to have NPC focus originated from the recess.</p><p><b>CONCLUSION</b>Our data suggest that the roof of nasopharyngeal cavity may be the area likely to develop the original NPC micro-focus, followed in frequency by the posterior wall, with the recess the least likely. The recess involvement observed in advanced lesions may be the extension of the NPC focus from the original site on the roof or the posterior wall of nasopharynx.</p>