1. The parapharyngeal space is an inverted pyramidal space bounded by the skull base superiorly, the greater cornu of the hyoid bone inferiorly, and the carotid sheath posteriorly. (2) Salivary gland tumors, schwannomas, and paragangliomas are common tumor types found in the parapharyngeal space. (3) Evaluation involves imaging such as CT and MRI to determine tumor location, size, and relationship to surrounding structures, while biopsy is used for diagnosis.
2. PARAPHARYNGEAL SPACE
(lateral pharyngeal space, pharyngomaxillary space)
It is classically described as an inverted pyramidal shaped potential space
.
Bounderies Base lies superiorly at the skull base and comprises the
sphenoid and petrous portion of temporal bone .
Apex ----inferiorly at the level of greater cornu hyoid bone.
Medial surface---comprises superior pharyngeal constrictor muscle
,buccopharyngeal membrane and the pharynx.
Lateral suface-----medial pterygoid muscle,the ramus of mandible,deep
lobe of parotid gland and fascia of post. Belly of diagastric.
Posterior surface----bordered by carotid sheath
3. FASCIAL CONDENSATION
Two fascial condensation are present in parapharyngeal
space
1. Aponeurosis of Zuckerkandl and Testut which divide the
paraphyrngeal space into 2 compartment by joining the
styloid process to the tensor veli palatini.
2. Second condensation of cervical fascia form a band which
extend from styloid process to angle and post. Border of
mandible and form a stylomandibular tunnel
Tumors of deep lobe parotid gland can extend into
parapharyngeal space through this tunnel giving rise to a
dumbbell shaped tumour.
5. Compartment of parapharyngeal space
COMPARTMENT VESSELS NERVES Others
PRESTYLOID 1 Maxillary artery
2 Ascending
pharyngeal artery
1 Auriculotempora
l nerve
2 Lingual nerve
3 Inferior alveolar
nerve.
Fat,connective
tissue,
Deep aspect of
parotid gland
Lymph nodes
POSTSTYLOID 1 ICA
2 Internal jugular
vein
1 Cranial nerve
9th,10th,11th,12th,
2 Cervical
sympathetic chain.
Lymph node of
glomus bodies
6. CLINICAL SIGNIFICANCE
Radiological features-----
Displacement pattern of fat and internal carotid artery within the space
will aid in the localization of lesion.
In prestyloid space lesion---mc associated with deep lobe of parotid
gland and will deflect the carotid sheath and paraphyrngeal fat
posterolaterally and may have a rim of fat anteromedially
In poststyloid space lesion---- include neuroendocrine origin arising
from carotid sheath as carotid body tumors or vagal schwannomas or
neuroma of sympathetic chain.Lesion displaces parapharyngeal space
fat and internal carotid artery anteromedially.
8. PRIMARY TUMOUR METASTATIC LESIONS MISCELLANEOUS
1 salivary gland tumour(benign
and malignant
SCC of nasopharynx lipoma
2Neurogenic neoplasm
vagal schwannoma
sympathetic chain Sch.
vagal paragangliomas
neurofibromas
SCC of oral cavity sarcoma
3 Vascular and Lymphatic
lesios ----- ---carotid artery
aneurysm brachial cleft
cyst --Hemangioma --
-A V malformation
--Lymphatic malformation
Carcinoma of oropharynx lymphoma
Carcinoma of thyroid gland teratoma
9. Sign and Symptoms
1 Neck mass
2 Oropharngeal mass
3 Dyspnea
4 Cranial nerve deficit
5 Dysphgia or odynophagia may present.
6 Unilateral Conductive hearing loss due to ET blockage
7 Hoarseness of voice due to vagus nerve involvement
8 Horner syndrom due to sympathetic chain involvement
9 Rhinolalia clausia due to oropharyngeal component.
10 Trismus due to pterygoid muscle involvement.
11 Cranial nerve deficits
12 symptoms of catecholamines excess
10. …
13. tumor involve prestyloid area
displace lateral pharyngeal wall and tonsil medially.
lump behind the angle of mandible.
14. tumour involve poststyloid area
fusiform appearance of tumour eg nerve sheath tumour.
Intracranial extension via carotid canal ,jugular foramen,foramen ovale.
13. EXAMINATION
Detailed head and neck examination.
Cranial nerve examination.
Bimanual palpation
Bruit / thrill
Carotid tumour moves side to side but fixed when moved up and down.
Vitals ----blood pressure ,pulse rate,
14. Salivary gland neoplasms
Neoplasms of salivary gland origin are located in the prestyloid parapharyngeal
space (PPS) and account for 40-50% of PPS lesions.
Salivary neoplasms may arise from the deep lobe of the parotid gland, ectopic
salivary rests, or minor salivary glands of the lateral pharyngeal wall.
The most common prestyloid PPS lesion is pleomorphic adenoma, which
represents 45-64% of salivary neoplasms in the PPS.
Common benign neoplasms include pleomorphic adenomas, monomorphic
adenomas, Warthin tumors, and oncocytomas.
Malignant neoplasms include adenoid cystic carcinomas, mucoepidermoid
carcinomas, adenocarcinomas, and acinic cell carcinomas. Approximately 20% of
all salivary lesions in the PPS are malignant, with carcinoma ex pleomorphic
adenoma and adenoid cystic carcinoma being the most frequently reported.
15. SCHWANNOMAS
Neurilemmomas, or schwannomas, arise from any nerve surrounded by Schwann
cells and fibroblast supporting the nerve.
Present in patients between 30 nd 70 yrs of age.
In the PPS, the most common sites of origin are the vagus nerve and the
sympathetic chain.
They grow slowly and rarely cause palsy of the nerve of origin.
Nerve paraesthesia common in these.
Neurilemmomas are encapsulated and histologically distinct from the nerve itself.
Treatment is by enucleation, and preservation of the nerve of origin is usually
possible; however, every patient should be cautioned about the possibility of
postoperative paralysis
16. PARAGANGLIOMAS
Paragangliomas are benign vascular neoplasms that arise from the paraganglia or extra-
adrenal neural crest tissue.
Paraganglia function as chemoreceptors and are associated with the carotid body, the jugular
bulb, and the vagus nerve in the poststyloid PPS.
Highly vascular tumor.
Carotid body tumors, glomus jugulare, and glomus vagale are slow-growing paragangliomas
that may not produce symptoms
may cause cranial nerve (CN) deficits, bone erosion, or intracranial extension as they increase
in size.
These are mobile in lateral direction not in cephalocaudal direction.
Approximately 2% of head and neck paragangliomas secrete catecholamines and may cause
paroxysmal symptoms of catecholamine excess.
17. ..
Ten percent of paragangliomas are multiple and associated
with paraganglioma at other locations.
Ten percent of paragangliomas are hereditary, associated with
a familial paraganglioma syndrome. ( genetic origin related to SHD sucinyl
dehydroge gene locus)
Head and Neck paraganglioma may also be associated with MEN 2a and MEN 2b
syndromes
Hypertension and flushing are suggestive of either a secreting
paraganglioma or an associated pheochromocytoma.
Malignant paragangliomas occur in less than 5-13.5% of patients
and are associated with rapid growth and development of metastatic
disease
Carotid para ganglioma mobile in lateral direction but not in
cephalocaudal direction , which differentiated it from lymph
node.(fontaine sign)
18. CAROTID BODY TUMOUR
Carotid body tumour, also known as a chemodectoma or carotid body
paraganglioma, are highly vascular tumors arising from the paraganglion cells of the
carotid body. These tumors are located at the site of the carotid bifurcation.
Shamblin classification helps in predicting the prognosis and difficulties for surgical
resection
Shamblin classification
Shamblin, et al. in 1971 classified carotid body tumors in relation to the carotid vessels.
In his classification
Group I – includes localized tumors not involving the carotid vessels.
Group II – tumors partially surround carotid vessels or is adherent to them.
Group III – defined as larger tumors encasing the carotid vessels.
As carotid body tumors become larger in size they get more adherent to the vessels.
However, Shamblin classification had some limitations because it does not reflect how
deep tumor infiltrates through the wall of carotid vessels, which decides if it is possible to
preserve the carotid vessels.
19. …
Modified Shamblin classification
Luna-Ortiz, et al. in 2006 proposed modifications to Shamblin classification, to improve the
prediction of difficulties and complications.
They introduced a class IIIa, representing the old class III, and a class IIIb which includes
tumors of any class (I, II, or III) where there is infiltration of the vessel wall and not just
circumferential encasement.
20. ..
Need for vascular resection and reconstruction was significantly higher among
class IIIb tumors.
22. NEUROFIBROMA
Neurofibromas, in contrast, are unencapsulated and intimately involved with the
nerve of origin.
They may occur as a manifestation of the neurofibromatosis-1 (NF-1) syndrome.
a disease in which the incidence of malignant transformation is increased.
Cystic degeneration is common.
The nerve of origin is usually sacrificed during excision to ensure complete
removal of the neoplasm.
23. METASTASIS TO THE PARAPHARYNGEAL
SPACE
In parapharyngeal space lymph nodes are present which drain the mucosa of the
upper aerodigestive tract and viscera of the neck .
The most common metastasis to the parapharngeal space is from nasopharyngeal
cancer .
Nodes may also involved in tonsil and tongue base cancers and maxillary sinus
cancer.
Other primary sites include thyroid and parotid glands.
Space may be directly invaded by malignancy from nasopharnx, tonsil, retromolar
trigone, palate and tongue base.
24. Lymphoreticular lesions
Lymphoreticular lesions make up 10-15% of PPS lesions. [3, 22] The lymphatics of
the PPS may be involved primarily or secondarily by carcinoma, or they may be
involved by infectious or inflammatory processes. Lymphoma is the most common
malignant lymphoid process, but metastases from thyroid cancer, osteogenic
sarcoma, squamous cell carcinoma, renal cell carcinoma, hypernephroma, and
meningioma may also appear as PPS masses. The most common lymphoreticular
lesions are lymphomas and metastases
25. INVESTIGATION
Fine slice CT and MRI provides the detail reqired.
MR Angiography and Carotid angiography provide information regarding vascularity and
relationship to the neurovascular structures.
FNAC
BIOPSY ( EXCISIONAL , INCISIONAL—FROZEN SECTION,TRANSORAL FNAC IS
SAFE AND INTRAORAL INCISIONAL BIOPSY MUST NOT BE CARRIED OUT.)
BALLON OCCLUSION TEST
24 HOURS VMA(VANILLYLMANDELIC ACID) ---measures amount of VMA in urine over24
hr to detect excess epinephrine and norepinephrine.
PLASMA CATECHOLAMINES LEVELS.
METAIODOBENZLGUANIDINE SCAN. (MIBG) ---radioactive material injected intravenous
,which is takeup by tumour cells and this is sccaned by a scanner to locate and confirm
the presence of tumour.
26. ..
In imaging (MRI) paraganglioma gives salt and pepper appearance
LYRE SIGN (splaying of internal and external carotid arteries) in vascular carotid body tumor.
CT Scan shows evidence of bony details and erosion by these tumours.
MRI Scan show soft tissue extension of these tumours including intracranial.extension.
MRI Scan with gadolinium also show involvement of nerves and perineural spread..
36. 1 TRANSCERVICAL APPROACH
It is the most commonly utilized approach.used in about 46% of cases.
It is ideal for small benign tumors independent of deep lobe involvement of parotid gland.
For poststyloid and prestyloid space tumours.
Incision given 2 finger(5 cm) breadth below mandible.
Submandibular triangle exposed (if needed)
Facial nerve branches preserved.
Facial artery ligated and divided.
Submandibular gland retracted or excised.
Digastric tendon divided
Mandibulectomy done (if needed)
38. TRANSCERVICAL TRANSPAROTID
APPROACH
Next most common approach. Used in 27% cases.
For lesion involve deep lobe of parotid tumours, vascular tumours.
Doubly modified blair incision or slight anterior extension (in front of ear) of cervical
incision i .
Same procedure as in transcervical approach.
Division of stylomandibular ligament ,styloglossus,stylohyoid muscle
Deep parotid lobe tumours
39. MANDIBULOTOMY
Transcervical and transcervical transparotid approaches can be combined with
a mandibular osteotomy.
Better visual asses to superior aspect of parapharyngeal space and the skull
base.
Inverted L OSTEOTOMY or double osteotomy above lingual and in front of the
mental foramen to protect the inferior alveolar nerve.
For excision of infiltrating malignancy and multifocal recurrent benign tumours.
40. TRANSORAL ROBOTIC SURGERY
(TORS)
1 It has technical advantage ,it being the 3D high resolution image with magnification.
2 Scaled movement and tremor filtration allow for deldicated dissection around tumour
capsule ensuring resection with a margin.
3 Ideal for benign salivary gland tumour in prestyloid space.
4 Absolute contraindication tumour that is adherent or involving the carotid artery, vascular
tumor ,dumbbell tumor with significant involvement of deep lobe of parotid gland.
41. RADIOTHERAPY
POST OP radiotherapy ---extensive malignant head and neck tumours
Irresectable tumours.
Control/ Arrest the growth of tumours.
Nasopharyngeal tumour.
Recurrent deep lobe of parotid tumour.
Regional lymph node metastasis.
Paraganglioma
42. CHEMOTHERAPY
RHABDOMYOSARCOMA AND OTHER SARCOMAS
NASOPHARYNGEAL TUMOUR.
DOXORUBICIN---GLANDULAR TUMOUR
CISPLATIN AND 5 FLUOROURACIL----SQUMOUS CELL TUMOURS