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Download PAROTID GLANDS - Chennai City Branch Of ASI
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Dr.K.Kuberan M.S Professor of surgery Govt.Royapettah Hospital Largest salivary glands lying largely below the external acoustic meatus between mandible and sternocleidomastoid muscle and it also projects forwards on the surface of masseter Ectodermal in origin Each parotid is developed during 5th week from angle of primary oral fissure. The groove is converted into tube which forms duct and opens into angle of primitive mouth. With the growth of maxillary and mandibular process the duct opening is shifted to vestibule opposite the upper 2nd molar tooth. During development the gland lies in between the branches of facial nerve, as development progresses it envelopes the branches. Superficial part(80%)lies over posterior part of ramus of mandible Deep part(20%) lies behind mandible and medial pterygoid Facial nerve lies between them The gland has a capsule of its own of dense connective tissue but is also provided with a false capsule by investing layer of deep cervical fascia. Skin Superficial fascia Superficial lamina of investing layer of deep cervical fascia Great auricular nerve (anterior ramus of C2 and C3) Mandibular ramus, Masseter and medial pterygoid muscles • • • Mastoid process Styloid process Carotid sheath with its contained neurovasculature (Common and Internal Carotid artery, Internal Jugular vein, vagus nerve) Superior pharyngyeal constrictor muscle From lateral to medial Facial nerve Retromandibular vein (Patey's fascio venous plane) External Carotid artery External carotid artery Retromandibular vein Superficial and deep group of parotid lymph nodes. Efferents from these nodes drain into jugulodigastric group of deep cervical nodes Parasympathetic – stimulates watery secretion Sympathetic – stimulates mucus rich thick secretion and also vasomotor Also known as Stensen’s duct Appears at the anterior part of upper border of gland and passes across masseter to traverse buccal fat and buccinator. Runs obliquely forwards for a short distance between buccinator and the oral mucosa and opens upon a small papilla opposite upper 2nd molar tooth. Infections • • – Very painful due to unyielding nature of capsule. Retrograde bacterial infection may occur from mouth via duct. Viral – mumps, coxsackie A & B, parainfluenza 1 & 3 Bacterial – staphylococcus aureus,streptococcus viridans Poor oral hygiene HIV Radiotherapy Syphilis Sjogren’s syndrome Painful diffuse swelling Fever,malaise Warmth, Tender Regional lymph node enlarged Caused by paramyxovirus Incubation period 2-3 weeks Bilateral 90% Common in children Clinical features:Fever Swelling Pain, tender Orchitis Oophoritis Pancreatitis Meningoencephalitis Ultrasound Calculous Abscess Meticulous oral hygiene Analgesics Antibiotics Soft diet Parotid abscess-I&D (Hiltons method) Age 3-6yrs Recurent episode of pain Diffuse swelling Fever Enlarged lymph nodes Spontaneus resolution In Adults Calculous- Unilateral Auto immune-Bilateral Diffuse swelling Pain Purulant saliva Pressure on sialectic gland may express pus from the duct. Xray Plain films are not much useful since parotid stones are radiolucent. Sialography Punctate sialectasis(snowstorm)appearance Extraction of stone through oral cavity Conservative parotidectomy if multiple calculi ADENOMA pleomorphic -pleomorphic adenoma monomorphic-warthin’s tumor Oxyphilic adenoma CARCINOMA (low grade) : acinic cell carcinoma adenoid cystic carcinoma low grade mucoepidermoid High grade adenocarcinoma squamous cell carcinoma high grade mucoepidermoid carcinoma Non epithelial tumors haemangioma lymphangioma Lymphomas primary- non-hodgkin’s secondary- lymphoma in sjogren’s Secondary tumors Unclassified tumors Tumor like lesions solid lesions cystic lesions RULE OF 80 80% of salivary neoplasms are of parotid origin 80% of parotid masses are neoplastic 80% of neoplasms in parotid are benign Intercalated Ducts ◦ ◦ ◦ ◦ ◦ Pleomorphic adenoma Warthin’s tumor Oncocytoma Acinic cell Adenoid cystic Excretory Ducts ◦ Squamous cell ◦ Mucoepidermoid Striated duct—oncocytic tumors Acinar cells—acinic cell carcinoma Excretory Duct—squamous cell and mucoepidermoid carcinoma Intercalated duct and myoepithelial cells—pleomorphic tumors Most common parotid neoplasm Median age—Fifth decade Common in females Usually unilateral Slow growing mass(80%) Lobular Not well encapsulated Malignant degeneration (2-10%) Mobile Nontender Firm Solitary mass in parotid region Raised ear lobule Obliteration of retromandibular groove Cannot be moved above zygomatic bone Deviation of uvula & pharyngeal wall towards midine if deep lobe involved No facial nerve involvement Greyish white in color with possible cyst formation and haemorrhage. Mixture of epithelial, myoepithelial and stromal components Epithelial cells: nests,sheets, ducts, trabeculae Stroma: myxoid, chrondroid, fibroid, osteoid No true capsule Tumor pseudopods Arise from deep lobe Swelling in the lateral wall of pharynx Soft palate displaced to opposite side Rapid increase in size Pain and nodularity Involvement of skin & ulceration Involvement of masseter Involvement of facial nerve Involvement of neck lymph node 2-4% of all salivary gland neoplasms 4-6% of mixed tumors 6th-8th decades Parotid > submandibular > Minor salivarygland Risk of malignant degeneration 1.5% in first 5 years 9.5% after 15 years Presentation Longstanding painless mass that undergoes sudden enlargement Histology • Malignant cellular change adjacent to typical pleomorphic adenoma • Carcinomatous component: Adenocarcinoma Undifferentiated Second most common benign parotid tumour (5%) Most common bilateral benign neoplasm of parotid. Common in lower pole Slow-growing, painless mass Marked male predominance Sixth and seventh decade Hot spot in Tc99 scan Malignant transformation rare. ◦ Encapsulated ◦ Smooth/lobulated surface ◦ Cystic spaces of variable size, with viscous fluid, shaggy epithelium ◦ Solid areas with white nodules representing lymphoid follicles ◦ Papillary projections into cystic spaces surrounded by lymphoid stroma ◦ Epithelium: double cell layer Luminal cells Basal cells ◦ Stroma: mature lymphoid follicles with germinal centers May represent heterotopic salivary gland epithelial tissue trapped within intraparotid lymph nodes Rare: 2.3% of benign salivary tumors 6th decade M:F = 1:1 Parotid: 78% Submandibular gland: 9% Presentation ◦ Enlarging, painless mass Gross ◦ Encapsulated ◦ Homogeneous, smooth ◦ Orange/rust color Histology ◦ Cords of uniform cells and thin fibrous stroma ◦ Large polyhedral cells ◦ Distinct cell membrane ◦ Granular, eosinophilic cytoplasm ◦ Central, round, vesicular nucleus Electron microscopy: ◦ Mitochondrial hyperplasia ◦ 60% of cell volume Basal cell is most common: 1.8% of benign epithelial salivary gland neoplasms 6th decade M:F = approximately 1:1 Most common in parotid Trabecular • Cells in elongated trabecular pattern • Vascular stroma Tubular ◦ Multiple duct-like structures ◦ Columnar cell lining ◦ Vascular stroma Membranous ◦ Thick eosinophilic hyaline membranes surrounding nests of tumor cells ◦ “jigsaw-puzzle” appearance Malignant – 1.Mucoepidermoid carcinoma 2. Adenoid cystic Carcinoma. 3. Adenocarcinoma. 4. Squamous cell carcinoma. 5. Malignant pleomorphic adenoma. 6. Acinic cell tumor 7. Malignant lymphoma 8. Anaplastic carcinoma Painless asymptomatic mass (80%) Pain=> perineural invasion (30%) Facial nerve palsy or paresis (7-20%) H/o prior parotid tumor indicates recurrence. Trismus => advanced disease with extension to masticatory muscles or less commonly invasion into TM joint Dysphagia => tumour of deep lobe of parotid Ear pain=>extension into auditary canal Numbness along Trigeminal nerve =>neural invasion Hard mass in parotid region Skin ulceration/fixation Fixation to adjacent structures Examination of external auditary canal for tumor extension Regional lymph adenopathy Blood or pus from stensen’s duct Bulging of lateral pharyngeal wall or soft palate Most common salivary gland malignancy 5-9% of salivary neoplasms Parotid 45-70% of cases Palate 18% 3rd-8th decades, peak in 5th decade F>M Slow growing tumors Limited local invasiveness Low metastatic potential High grade behave like SCC, low grade behave like benign tumors Sucessfully treated by adequate radical excision Presentation ◦ Low-grade: slow growing, painless mass ◦ High-grade: rapidly enlarging, +/- pain Gross pathology ◦ Well-circumscribed to partially encapsulated to unencapsulated ◦ Solid tumor with cystic spaces Areas of mucous secreting cells Epidermoid and epithelial cells Poorly encapsulated infiltrating tumors Propensity to spread along nerves Highly invasive but may remain quiescent for a long time Highest incidence of distant metastasis Lung metastasis are most frequent. Poor prognosis They can arise within a preexisting benign pleomorphic adenoma (CARCINOMA EX PLEIOMORPHIC ADENOMA) They may arise denovo (CARCINOSARCOMA) Intermediate grade malignancy Low malignant potential May be bilateral or multicentric Rarely metastasize May spread along perineural planes Most commonly in elderly females Usually Non-Hodgkins 5-10% of patients with warthin’s Enlarged parotid with a rubbery consistency Enlarged regional lymph nodes Squamous cell carcinoma Sebaceous carcinoma Salivary duct carcinoma Malignant fibrohistiocytoma Ultrasound FNAC is the diagnostic MRI is superior in demonstrating benign tumors than CT CT scan/MRI identifies regional lymph node involvement/ extension into deep lobe / parapharyngeal space PET may be useful in assessing malignant tumors Efficacy is well established Safe, well tolerated Accuracy = 84-97% Sensitivity = 54-95% Specificity = 86=100% First line of management superficial lobe is involved, superficial conservative parotidectomy If deep lobe(dumb bell) also involved, total parotidectomy with preservation of facial nerve. Enucleation should be avoided as recurrence rate is high Extracapsular enucleation-warthin’s tumor ◦ RADICAL PAROTIDECTOMY Removal of the entire gland,facial nerve and regional lymph nodes Resection of all involved structures positive malignancy nodes high grade tumors local invasion recurrent tumors if no h/o previous neck dissection deep lobe tumors Skin grafting Cervicofacial flap Trapezius flap Pectoralis flap Deltopectoral flap Microvascular free flap Great auricular nerve Hypoglossal nerve Sural nerve >4 cm in diameter High grade Local invasion Lymphatic/neural/vascular invasion Tumor in/extending to deep lobe Recurrent tumours following re-resection Positive margins High grade Neural involvement Locally advanced disease Advanced age Associated pain Regional lymph node metastasis Distant metastasis Inflammation: whole parotid swollen Neoplasm:A part of the gland is swollen
