Familial Nasopharyngeal Carcinoma 6

Imaging in the Diagnosis and Staging of Carcinoma of Nasopharynx 85earliest imaging sign of pterygopalatine fossa involvementis obliteration of its normal fat content (Fig. 8.3).The pterygopalatine fossa is a major crossroad withinthe deep face, from where tumors may infiltrate:●The maxillary nerve and extend perineurallythrough the foramen rotundum into the intracranialcavity (Chong and Fan 1996a).●●●Along the vidian canal posteriorly through theforamen lacerum into the petrous carotid canal.Laterally through the pterygomaxillary fissureinto the masticator space (Fig. 8.3).Superiorly through the inferior orbital fissureinto the orbital apex, with subsequent intracranialextension via the superior orbital fissure(Fig. 8.4).abcFig. 8.4. A series of three axial contrast-enhanced CT imagesfrom inferior to superior. Image (a) shows a nasopharyngealcarcinoma invading the left pterygopalatine fossa and masticatorspace (asterisk) through an enlarged sphenopalatineforamen (arrow). Image (b) shows that the tumor infiltratessuperiorly through the inferior orbital fissure into the left orbitalapex (arrow). Image (c) shows that the tumor (asterisk)extends via the superior orbital fissure into the intracranialcavity and involves the left cavernous sinus (arrow)