fossa of the mandibular condyle

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1 The Road Map For Diagnosis And Management Of Parapharyngeal Tumors Professor: Hossam Thabet, MD. Otolaryngolgy-Head & Neck Suegery Alexandria University, Egypt Fakhry & Al Rajhi Hospital, Saudi Arabia

2 0.5% of fh&nt tumors Introduction Benign: 80% Malignant: 20% Preoperative imaging is essential for diagnosis & proper treatment planning Surgical resection is the mainstay of therapy Recurrence 0-9% for benign PPS tumors 25-77% for malignant PPS tumors

3 Anatomy Potential deep neck space lateral to upper pharynx 5 sided Inverted pyramid with base at skull base, apex at greater cornu of the hyoid bone Anatomy Fascial Compartmentalization Tensor-vascular-styloidstyloid fascia extends from tensor veli palatini to styloid process and its muscle complex. It divides PPS into; Prestyloid compartment(anterolateral anterolateral)-deep lobe of parotid, fat, & lymph nodes Poststyloid t compartment t(posteromedial posteromedial)-ica, IJV, CNs IX-XII, XII, sympathetic chain, & lymph nodes Stylomandibular ligament & tunnel Stylomandibular tunnel formed between the ligament, the skull base and the ramus of the mandible.

4 Anatomy Fascial Compartmentalization Tensor-Vascular-Styloid Fascia & Styloid diaphragm Bejjani, G K. et al Neurosurgery 1998; 43(4): MLDCF: middle layer of deep cervical fascia, DLDCF: deep layer of deep cervical fascia (from Som PM, Curtin HD. Normal Anatomy of the Neck. In: Head and Neck Imaging: 1996: 730).

5 Med. Pt. ms & fascia Mandible (ascending ramus) Deep lobe parotid Post. belly of the digastric m. Sphenomandibular ligament Stylomandibular ligament Lateral wall M Pterygomandibular raphe medial pterygoid muscle fascia Buccoph. fascia/ superior ph. constrictor m. Vertebral fascia & paravertebral muscle, & Dorsal layer of fascia of the carotid sheath Anatomy: Superior Boundary clivus fossa of the mandibular condyle The superior limit of the PPS is a small portion of the temporal bone. It includes the carotid canal, jugular foramen, and hypoglossal foramen. Inf. tympanic canaliculus

6 1. Med. Pt. f (medial wall of the masticator space) & 2.Tensor veli palatini fascia ( medial wall of prestyloid PPS) tapering towards the skull base. A lesion in the prestyloid space (between 1&2) would extend up into a blind pouch. Lesion in the masticator space extends upward in to f. ovale There is a fascial connection from the medial pterygoid plate to the spine of the sphenoid at the superior medial wall, which crosses medial to f. ovale & f. spinosum, which are not included in the superior limit of PPS but rather in the infratemporal fossa or masticator space Curtin 1987, Rdil Radiology;163: Faik Ö M, etal. Neurosurgery2003.

7 Relationship with the other spaces of the neck Laterally, the masticator & parotid spaces Medially, the pharyngeal mucosal space Posteromedially, the retropharyngeal space Shin JH et al. AJR 2001; 177: Communications Anatomy PPS is connected to the retroph. Space in an area medial to the carotid sheath & its contents. Antero-inferiorly, there are connections with the other spaces located about FOM & Submandibular gland. Shin JH et al. AJR 2001; 177:

8 Pathology of PPS Neoplasms Pi Primary Neoplasms (80 80% benign & 20% malignant) Salivary gland tumors (40-50 %) Neurogenic i tumors ( %) Miscellaneous tumors (20 %) Direct Extension Metastasis Poststyloid Compartment Prestyloid Compartment Poststyloid: Schwannoma Paraganglioma Prestyloid: Salivary gland neoplasm from deep lobe of parotid or minor salivary glands 10 % of parotid tumors arise from deep lobe Neurofibroma Ganglioneuroma <1 % of deep lobe tumors involve the PPS < 5% parotid tumors involve the PPS

9 Salivary Gland Tumors Most common 1ry PPS tumor 40-50% Pleomorphic adenoma % Located in prestyloid space From deep lobe of parotid or minor salivary glands On CT or MRI a fat plane between the parotid and a prestyloid mass indicates minor salivary gland origin Displace the ICA posteriorly Neurogenic Tumors % of PPS lesions Second most common 1ry PPS tumor Benign & Slow growing Displace ICA anteriorly Most common poststyloid tumors Neurilemomas (Most common) 50 % Paragangliomas (2 nd common) 35 % Neurofibromas (3 rd common) 5 % Ganglioneuroma

10 Miscellaneous Tumors Congenital (Branchial cleft cyst, dermoid, teratoma,hemongioma, lymphangioma, arteriovenous malformation). Vascular (Hemangiopericytoma, angiosarcoma, ICA aneurysm) Lymphoma & Lymphoreticular lesions Muscle (Rhabdomyoma, Leiomyoma, rhabdomyosarcoma) Connective tissue (Lipoma, fibroma, fibosarcoma, chondrosarcoma) Meningioma, Meningiosarcoma. Pseudotumor sclerosing cervicitis, myositis, abscees, aneurysm. Malignant invasion from surrounding structure Distant metastases Clinical Presentation Neck mass (53%) Oropharyngeal bulge (51 51%) Unilateral E.T. dysfunction (OME) Dysphagia &/or Dyspnea Airway obstruction & OSAS C.N. deficits (hoarseness globus, VC palsy) Horner s Syndrome Pain, Otalgia &/or pulsatile tinnitus, bruit, thrill Ti Trismus & &d dysarthria Catecholamine excess Sx, hypertension, flushing Cranial nerve paralysis, pain, &/or trismus suggest malignancy

11 Lab. Studies Routine studies 24-hour urine catecholamines VMA Metanephrines Imaging Studies CT MRI/MRA Diagnostic work Up FNAB Other Studies Balloon occlusion test MIBG scan Metastatic workup & panendoscopy Work up for multiple paragangliomas 4 vessel angiography CT adrenal glands angiography CT adrenal Imaging Of PPS Lesions CT/CTA MRI/MRA Angiography g Equal efficacy in localizing the lesion to the prestyloid or poststyloid space Angiography (Reserved for enhancing lesions) Imaging studies should be obtained prior consideration of fbi biopsy, because, one often can make a diagnosis i on the basis of imaging g without the need for FNAB

12 Imaging Of PPS Lesions Imaging g studies should answer the following questions: 1. Is the mass prestyloid or poststyloid? 2. What is the relationship to the parotid gland? 3. What is the relationship to the great vessels? 4. What are the soft tissue characteristics of the tumor? Imaging Of PPS Lesions Prestyloid lesions Lie antero-lateral to the styloid process Displace PPS fat pad postero-medially Located anterior to the great vessels. Poststyloid lesions Lie postero-medial to the styloid process Displace PPS fat pad antero-laterally,, between the mass and the pterygoid muscles Located posterior to great vessels

13 Prestyloid Minor S.G.tumor Prestyloid Deep lobe parotid Poststyloid Tumor Masticator Space Tumor Whyte AM, Hourihan MB. The British Journal of Radiology1989:62; Parapharyngeal Tumors Prestyloid lesions Antero-lateral to styloid process Posteromedial PPS fat Displacement Anterior to carotid vessels CT Poststyloid lesions Postero-medial to styloid process Anterolateral PPS fat Displacement Posterior to carotid vessels Non Enhancing Enhancing Non Enhancing Enhancing Calcifications Isodensity Low density Lymph N. Lucent line between mass & parotid Lipoma Hemangioma Med. P. No lucent line between mass & parotid Uniform? Paraganglioma Vascular CT angiography Nonuniform? Schwannoma Meningioma A Vascular Paraganglioma Metast. Thyroid.Ca Extraparotid SGT Deep lobe parotid t. ICA anurysm Hemangioma Schwannoma

14 Parapharyngeal Tumors Prestyloid lesions Antero-lateral to styloid process Posteromedial PPS fat Displacement Anterior to carotid vessels MRI MRA Poststyloid lesions Postero-medial to styloid process Anterolateral PPS fat Displacement Posterior to carotid vessels SGT(Pl.adenoma) Schwannoma Paraganglioma Low signal intensity on T1 High signal intensity on T2 Displace CA posteriorly High signal on T2 Displace CA anteriorly Enhance with GD Lack flow voids salt and pepper appearance on T2 Displace CA anteriorly Numerous flow voids Metastatic Thy. ca Ftli Fat line bt between No Fat line between Or hypernephroma Lymph node mass & parotid mass & parotid As paraganglioma Low intensity on T1 Local infiltration of High intensity on T2 Fat planes, muscles Displace CA anteriorly Extraparotid SGT Deep lobe parotid t. or skull base Homogeneous Irregular borders Lobulated, smooth Parapharyngeal Tumors Imaging CT & MRI? Malignant Benign High-grade grade malignancies Ill-defined infiltrating margins low signal intensity on both T1 & T2-weighted sequences Low-grade malignancies are bright on T2-weighted images. Metastatic hypernephroma, & thyroid carcinoma appear similar to paraganglioma but with irregular borders Smooth margins Distincit regular borders Bright on T2 W-images

15 Tumor T1 MRI T2 MRI Contour Overall appearance Relation to CA Calcification, fibrosis, or bone Para ganglioma Intermed Mod. High salt&pep. if>1.5 cm smooth Flow void common Enhancing Posterior _ Pl. Adenoma Low High smooth No flow void Anterior _ Warthin t. Homog. Intermed -Hyper Intermed _focal hyperint. smooth No flow void No enhancing Anterior _ Schwannoma Low High smooth No flow void Enhance,GD Posterior _ Lymph n. Low Mod.High smooth No flow void Homogeneous Enhance,GD Posterior _ Ca.Ex.Pl.A. Intermed Low- Intermed ed irregular No flow void Anterior _ Met. Th.ca Intermed high irregular Rare fluid void Posterior ± CT Scan Imaging Of PPS Lesions Localize a mass to the prestyloid or poststyloid space. Deep lobe parotid vs minor SGT The relationship of the mass to the great vessels Enhancing lesions (Schwannoma, paraganglioma, hemangioma, hemangiopericytoma, aneurysm) Demonstrates calcifications & bony involvement. Wide availability & lower cost. Limited soft tissue detail Risk of exposure to radiation & IV contrast

16 Prestyloid Minor S.G. Pleomprphic Adenoma Vagal Schwannoma

17 Sympathatic Schwannoma Neurofibroma

18 Enhancing soft-tissue tissue masses at characteristic locations is typical & the key to diagnosis of paraganglioma Enhancing mass at the level of carotid bifurcation, splaying ICA &ECA arteries medially or laterally is characteristic for CBT Vagal Paraganglioma Enhancing soft-tissue tissue masses at characteristic i locations is typical l& the key to diagnosis of paraganglioma Enhancing h i mass along the course of IJV & ICA above the carotid bifurcation, below the skull base with displacement of adjacent vascular structures anterolaterally or anteromedially is characteristic for vagal paraganlioma

19 Vagal Paraganglioma Vagal lp Paraganglioma displacing i the carotid vessels laterally ll Vagal lp Paraganglioma Angiography

20 Vagal Paraganglioma Vagal Paraganglioma displacing the carotid vessels medially Vagal Paraganglioma g Bilateral vagal paraganglioma displacing the carotid vesseles Bilateral vagal paraganglioma displacing the carotid vesseles anterolaterally

21 Parapharyngeal Lipoma Metastatic Sq C.Ca

22 Rt. Lymphoma Imaging Of PPS Lesions MRI The study of choice (greater soft tissue resolution & vascular information) % accuracy in preoperative e diagnosis Superior to CT in delineating soft tissue characteristics of PPS tumors Dfi Define the relationship lti of fth the tumor to the great vessels & ICA & IJV involvement better than CT (Olsen WL, 1987)

23 Imaging Of PPS Lesions MRI Better delineation of intracranial extension Differentiate between tumor & muscle Detect paragangliomas < 5 mm, whereas CT demonstrates only lesions > 8 mm (Vogl T etal., van Gils AP.etal., 1992) Vogl T etal., 1989 & Recommended in poststyloid & malignant masses to evaluate the extent of the swelling & rule out intracranial extension. (superior soft tissue & vascular resolution) MRI Imaging Of PPS Lesions Determination of bone involvement is poor Contraindicated in patients with pacemakers, with certain hardware, are & who have claustrophobia. The cost is significantly greater CT & MRI are complementary, and both should be obtained in the evaluation of extensive lesions or when there is suspicion of malignancy.

24 Imaging Of PPS Lesions MRI: Pleomorphic Adenoma Intermediate signal on T1-weighted images Iso-hyperintense signal on T2-weighted images. Homogeneous or heterogeneous contrast enhancement Malignant carcinoma ex pleomorphic adenoma shows change from high T2 signal in benign tumors to low-to to- intermediate T2 signal in malignant masses. Imaging Of PPS Lesions MRI: Warthin s Tumor Homogeneous intermediate-hyperintense signal on T1-weighted images Intermediate signal intensity with focal hyperintense areas on T2-weighted images. No enhancement with contrast.

25 Imaging Of PPS Lesions MRI: Paraganglioma Salt and pepper appearance on T2 weighted images because of numerous flow voids Isointense on T1-weighted MRI Hyperintense on T2-weighted MRI, relative to skeletal muscle. Intense tumor enhancement MRA may be useful in defining the flow-related enhancement of feeding vessels in lesions > 1.5 cm Imaging Of PPS Lesions MRI: Schwannoma Higher signal intensity on T2 images like pleomorphic adenomas, but displace CA anteriorly Enhance with gadolinium Lack flow voids

26 Dumbbell shaped deep lobe parotid mass Originate lateral to, & grow medially through the Stylomandibular tunnel which resists pressure & does not expand, therefore, deep lobe tumors assume dumbbell shape as they grow into it Present with a pretragal swelling with palatal & pharyngeal swelling with ballotement Round shaped deep lobe parotid mass Round Originate posterior or medial to Stylomandibular tunnel & grow into the PPS pushing the soft palate medially resulting in round tumors No pretragal swelling Sometimes, submandibular fullness Palatal & pharyngeal swelling with ballotement

27 Growth & Spread Of PPS Tumors PPS tumors are bounded d by bone & thick fascia on 3 sides; 1. Superiorly: Skull base, 2. Posteriorly: Cervical spine & prevertebral ms. & fascia, 3. Laterally: mandibule & pterygoid muscle Deep lobe parotid & paraphartyngeal tumors may grow medially and bulge into the tonsillar area, soft palate, and nasopharynx. Posterolateral growth causing retromandibular swelling. Inferior growth causing an upper neck swelling between parotid tail and submandibular gland..

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30 T1 MRI No contrast T1 MRI with Contrast & Fat Suppression T2 MRI T2 with Fat Suppression

31 Prestyloid Deep Lobe parotid Warthin s Dumbbell Tumor

32 Prestyloid Deep Lobe parotid Warthin s Tumor T1 MRI with GD T1 MRI Prestyloid Deep Lobe parotid Warthin s Dumbbell Tumor T1 MRI with GD T1 MRI

33 Prestyloid Deep Lobe parotid Warthin s Dumbbell Tumor T2 MRI T1 MRI Angiography For all enhancing & malignant lesions L Lyre sign Define vascular anatomy Gold standard for relationship to great vessels Differentiate neurogenic and vascular Remember lyre sign Balloon occlusion test if possible sacrifice Tumor embolization 1 day prior to surgery

34 Surgical Therapy Surgery is the mainstay of treatment The choice of surgical approach is dictated by the size of the tumor, its location, its relationship to the great vessels, and suspicion of malignancy. Transoral Cervical Cervical (Submaxillary) Surgical approaches Cervical-Transmandibular Transmandibular (+ Lat. mandibulotomy) Cervical-Transpharyngeal swing (+midline mandibulotomy) Cervical-Parotid ± midline mandibulotomy Transparotid Infratemporal fossa Transcervical-transmastoid

35 PP Tumors Malignant Imaging Benign Prestyloid Poststyloid Deep lobe Parotid Minor SGT Small <5cm Large 5cm Very large, near skull base, CA compression Small <5cm Large 5cm Very large, near skull base, CA compression Transparotid Cervical- Cervical-Parotid Parotid + Midline Mandibulotomy Cervical Cervical- Sub.M Cervical-Parotid Cervical Sub.M Cervical-Parotid + Midline Mandibulotomy PP Tumors Malignant Imaging Benign Prestyloid Poststyloid Small<5cm low Non vascular Large5cm vascular Very large,high Near skull base, vascular Dumbbel Shaped Vagal paraganglioma Cervical Cervical - Submaxillary Cervical trans Pharyngeal (Midline Combined App. Cervical -Trans Cervical-Parotid mandibulotomy) Mastoid

36 PP Tumors? Malignant FNAB Transoral CT guided Imaging Benign Malignant Lymphoma Prestyloid Poststyloid Cervical-Parotid +Midline Mandibulotomy Cervical Submaxillary Cervical-ParotidC i l P Radiotherapy + Midline Mandibulotomy PP Tumors + Suspected CA injury +ve BOT BOT -ve BOT Non Surgical Treatment Subtotal resection with CA preservation Revacularization (high risk for stroke) Xenon -CT Excellent perfusion Diminished Perfusion Cervical Transph. CA grafting or ligation (No risk for stroke) Cervical Transph. CA preservation CA grafting with bypass (low-mod. risk for stroke)

37 Transoral Unacceptable approach for most PPS lesions Very limited exposure No control of great vessels Increased risk of vascular injury Increased risk of infection Potential risk of facial nerve injury. Possibility of tumor spillage or incomplete removal Recurrence rate of 25% Described for small benign prestyloid minor SGT May be combined with an external approach to mobilize lesions with significant oropharyngeal component. Transoral

38 Disadvantages Limited exposure medially, superiorly & posteriorly Mandibulotomy is necessary for further exposure No vessel control at the skull base. Cervical Transcervical approach without entrance of submandibular triangle, for excision of small poststyloid tumors <5cm. Transcervical submaxillary app. for excision ii of poststyloid ttl id& prestyloid tl extraparotid lesions >5cm. Dissecting the submandibular triangle & sub.m.g. excision, division of digastric tendon, stylohyoid & styloglossal ms, and stylomandibular lig. with anterior mandibular retraction widens exposure by 50%, Rt.PP Neurofibroma

39 Vagal Paraganglioma Vagal Paraganglioma

40 Vagal Paraganglioma Recurrent Lt. Carotid.Paraganglioma

41 Recurrent Lt. Carotid.Paraganglioma Sympathatic Schwannoma

42 Cervical-Parotid Approach Indications Can be used to remove majority of PPS tumors All deep lobe parotid tumors & extraparotid minor SGT Low grade malignant tumors of deep lobe of parotid Poststyloid tumors, including small paragangliomas Cervical-Parotid In round tumors the facial nerve is not displaced laterally as in dumbbell tumors, therfore it is possible to remove these tumors by exposing only the trunk and not all branches

43 Cervical-Parotid

44 Transparotid Prestyloid Deep Lobe Parotid Warthin s Tumor

45 Transparotid Prestyloid Deep Lobe Parotid Warthin s Tumor Transparotid

46 Transparotid For deep lobe parotid tumors Superficial parotidectomy with facial nerve preservation Facial nerve retracted Dissect posterior & inferior around mandible May use mandibulotomy Indications Cervical-Transpharyngeal Vascular tumors with superior extension Malignant tumor Very Large tumors

47 Cervical-Transmandibular Transcervical-Transmastoid Transmastoid Cervical incision isi n carried postauricularly rl Mastoidectomy Remove mastoid tip exposing jugular fossa Facial nerve may need to be dissected from Fallopian canal

48 Nonsurgical Management Indications Poor surgical candidates Elderly patients Failed balloon occlusion test Unrespectable lesions Significant ifi risk of sacrifice of multiple l cranial nerves Patients with multiple paragangliomas who have preexisting contralateral C.N. deficits Nonsurgical Management Observation Rdi Radiation i

49 Key Points No rule for biopsy in diagnosis of PPS tumors Diagnosis is mainly by preoperative e imaging SGTs are prestyloid & Neurogenic tumors are poststyloid FNA may be used in suspecision of malignancy Round deep lobe parotid tumors originate medial or posterior to the stylomandibular ligament Key Points Round deep lobe parotid tumor originating medial to the stylomandibular ligament may be misdiagnosed as minor prestyloid SGT Surgical resection is the mainstay of therapy Cervical-Parotid approach for most of tumors Cervical submaxillary approach for Poststyloid tumors & Prestyloid minor SGT

50 Thank You