Parapharyngeal-tumor-slides-060322 - Primary Parapharyngeal...

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Unformatted text preview: Primary Parapharyngeal Tumors Tumors Jing Shen, M.D. Shawn Newlands, M.D., Ph.D University of Texas Medical Branch Department of Otolaryngology Grand Rounds Presentation March 22, 2006 Primary parapharyngeal tumors Primary Most of the tumors in parapharyngeal space Most are metastatic disease or direct extension from adjacent spaces from 0.5% of all head and neck tumors Benign tumor 80% Malignant tumor 20% Anatomy Anatomy Potential deep neck Potential space space Shaped as an Shaped inverted pyramid inverted Base of the pyramid: Base skull base skull Apex of the pyramid: Apex greater cornu of the hyoid bone hyoid Anatomy Anatomy Superior: small Superior: portion of temporal bone temporal Inferior: Inferior: junction of the posterior belly of the digastric and the hyoid bone bone Anatomy Anatomy Medial: pharyngobasilar fascia and Medial: pharyngeal wall pharyngeal Lateral: Lateral: medial pterygoid muscle fascia Mandibular ramus Retromandibular portion of the deep lobe of the Retromandibular parotid gland parotid Posterior belly of digastric muscle Anatomy Anatomy Lateral: two ligaments – Sphenomandibular ligament – Stylomandibular ligament Posterior: vertebral fascia and paravertebral Posterior: muscle muscle Anterior: pterygomandibular raphe and medial Anterior: pterygoid muscle fascia pterygoid Anatomy Anatomy Tensor-vascularstyloid fascia styloid separates parapharyngeal spaces to two compartments: compartments: – Prestyloid Prestyloid – Poststyloid Anatomy Anatomy Prestyloid compartment contents: – Retromandibular portion of the deep lobe of the Retromandibular parotid gland parotid – Minor or ectopic salivary gland – CN V branch to tensor veli palatini muscle – Ascending pharyngeal artery and venous plexus – Most fat Anatomy Anatomy Poststyloid compartment contents – Carotid artery – Internal jugular vein – CN IX to XII – Cervical sympathetic chain – Glomus tissues Differential diagnosis Differential Location of the tumor Location – Prestyloid: Prestyloid: salivary gland neoplasm salivary lipoma rare neurogenic tumors – Poststyloid: Schwannoma Paraganglioma neurofibroma Salivary gland neoplasm Salivary Most common primary parapharyngeal tumor Most (40%-50%) (40%-50%) Pleomorphic adenoma is most common From deep lobe of the parotid gland – extend through the stylomandibular tunnel, “dumbbell” extend appearance on CT scan appearance – displace tonsil and soft palate and cause obstruction of displace nasopharynx nasopharynx From minor salivary gland lying in parapharyngeal From fat Salivary gland neoplasm Salivary Malignant parapharyngeal salivary gland – Frequency varies from 24% to 75% – Mucoepidermoid carcinoma – Adenoid cystic carcinoma – Acinic cell carcinoma – Malignant mixed carcinoma – Squamous cell carcinoma – Adenocarcinoma – Malignant Warthin’s tumor Malignant Neurogenic tumor Neurogenic Second most common primary parapharyngeal Second tumor tumor – Schwannoma Vagus nerve Cervical sympathetic chain – Paraganglioma Vagal paraganglioma Carotid body tumors – Neurofibroma – Malignant neurogenic tumor Miscellaneous tumors Miscellaneous Clinical presentation Clinical Clinical detection is difficult Tumor size 2.5 to 3.0 cm to be detected Tumor clinically clinically Asymptomatic mass – Mild bulging of soft palate or tonsillar region – Palpable mass at angle of mandible Clinical symptoms Clinical Prestyloid – – – – Serous otitis media Voice change Nasal obstruction Dyspnea Poststyloid – Compress CN 9th, 10th, 11th, 12th or sympathetic chain – Hoarseness, dysphagia, dysarthria, Horner’s syndrome Cranial nerve paralysis, pain, trismus suggest Cranial malignancy malignancy CT scan CT Locates tumor to prestyloid vs poststyloid – Prestyloid tumor displace carotid artery posteriorly – Poststyloid tumor displace carotid artery anteriorly Fat plane between mass and parotid Enhancement of lesion – Schwannoma, paraganglioma, hemangioma, Schwannoma, hemangiopericytoma, aneurysm hemangiopericytoma, Bone erosion due to malignancy Limited soft tissue detail MRI MRI Most useful study Relationship of mass and carotid more Relationship easily seen than with CT easily Characteristic appearances of tumor types Characteristic on MRI allows preoperative Dx in 90-95% of patients patients MRI MRI Pleomorphic adenoma – – – Low intensity on T1 High intensity on T2 Displace carotid Displace posteriorly posteriorly MRI MRI Schwannoma – High intensity on T2 – Displace carotid Displace anteriorly anteriorly MRI MRI Paraganglioma – “salt and pepper” salt Angiogram – Define vascular anatomy – Carotid occlusion test – Tumor embolization 1 day prior to surgery FNA Transparotid approach Transparotid For deep lobe of parotid lesion Superficial parotidectomy with facial nerve Superficial preservation preservation Retract facial nerve from the deep parotid Retract lobe lobe Dissect posterior and inferior around Dissect mandible mandible Improve access by mandibulotomy Improve Transcervical approach Transcervical For poststyloid tumor Transverse incision at Transverse level of hyoid level Submandibular gland Submandibular removed or retracted removed Incision through the fascia Incision deep to the submandibular space space Increase exposure by Increase releasing digastric, stylohyoid, styloglossus from hyoid, cut stylomandibular ligament, mandibulotomy Cervical-parotid approach Cervical-parotid Extend cervical incision up infront of ear Identify facial nerve Divide posterior belly digastric Divide Divide styloglossus, stylohyoid close to Divide styloid process styloid Divide stylomandibular ligament Can combine with mandibulotomy Cervical-parotid approach Cervical-parotid Indications Indications Can be used to remove majority of the Can parapharyngeal tumor parapharyngeal – All deep lobe parotid tumors and extraparotid All salivary tumors salivary – Low grade malignant tumors of deep lobe of Low parotid parotid – Many poststyloid tumors, including most Many neurogenic tumors and small paragangliomas neurogenic Cervical-transpharyngeal Cervical-transpharyngeal “Mandibular swing” Midline lip splitting or visor Midline flap flap Mandibulotomy anteriorly, Mandibulotomy incise along floor of mouth to anterior tonsillar pillar to Identify hypoglossal nerve Identify and lingual nerve and Divide styloglossus and Divide stylopharyngeus muscle Need tracheotomy Cervical-transpharyngeal Cervical-transpharyngeal indications indications All vascular tumors that extend into the All superior portion of the parapharyngeal space space Malignant tumor invaded skull base or Malignant vertebral body vertebral Conclusion Conclusion Rare tumor in an complex anatomical area Subtle clinical presentation Radiographic imaging is important Prestyloid vs poststyloid space Surgery is the main treatment When not to operate ...
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This note was uploaded on 12/28/2011 for the course STEP 1 taught by Professor Dr.aslam during the Fall '11 term at Montgomery College.

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