There is a general confusion regarding management of lesions involving the masticator space
, according to AJCC staging such tumors are classified as T4b hence may or may not be operable.
T4 is further divided into T4a for tumors extending into the deep soft tissue, cartilage, bone, or overlying skin, and T4b for extension of tumors into the central nervous system (brain, dura), skull base, lower cranial nerves (IX, X, XI, XII), prevertebral or masticator space
, carotid artery, or mediastinal structures.
The masticator space
(MS) contains muscles of mastication (medial and lateral pterygoid, masseter, and temporalis), ramus of the mandible and the third division of the cranial nerve V (Figure 10A).
The CT scan revealed osteomyelitis of the right zygomatic arch and anterior wall of the maxillary sinus, with inflammatory changes in the masticator space
According to the seventh edition of the American Joint Committee on Cancer (AJCC) staging system in 2010, nasopharyngeal tumors with intracranial extension and/or involvement of cranial nerves, hypopharynx, or orbit or those with extension to the infratemporal fossa or masticator space
are defined as stage T4 .
That is, the adjusted T4 category includes the following structures: LPM, masticator space
beyond the lateral pterygoid, intracranial, cavernous, and PS structures.
There was no infiltration of the masticator space
or the overlying skin.
T4b: very advanced disease: tumour involving brain, dura mater, skull base, cranial nerves (IX, X, XI, and XII), masticator space
, carotid artery, prevertebral space, or the mediastinal structure.