Nasopharyngeal Carcinoma

Abstract

• The nasopharynx is a cubodial chamber that is posteriorly bound by the C1-C2 vertebral body and sphenoid bone. Anteriorly, it connects with the nasal cavity and begins at the posterior choanae. Inferiorly, it connects with the oropharynx and the superior surface of the soft palate forms the fl oor of the cavity (Fig. 1a ).• The eustachian tube is located in the lateral wall and bounded by a prominence known as the torus tubarius. Posterior to the torus is the fossa of Rosenmüller, which is the most common site for nasopharyngeal malignancies. In advanced cases, the tumor can invade the middle ear through the eustachian tube (Fig. 1b ).• Anteriorly, the tumor can extend into the nasal fossa (87 %) ( Fig. 7 ) and result in destruction of the pterygoid plates (27 %). Less commonly, the tumor can invade the ethmoid and maxillary sinus or infi ltrate the orbital apex.• Laterally, the tumor can extend into the parapharyngeal space (68 %), which is an important part of T staging for a tumor (Figs. 7 and 8b ). Extension into this space can occasionally lead to invasion of cranial nerves IX to XII in advanced disease. • Superiorly, nasopharyngeal carcinoma can directly invade the base of the skull, the sphenoid sinus, and the clivus (41 %). The foramen lacerum is a vulnerable spot through which the tumor may enter the cavernous sinus (16 %) and the middle cranial fossa to invade cranial nerves III to VI. The foramen ovale also allows access for the tumor to invade the middle cranial fossa, in addition to the petrous portion of the temporal bone (19 %), and the cavernous sinus.• The posterior extension of NPC is less common and can include invasion of prevertebral muscles (19 %) and inferior invasion of the oropharynx (21 %).