Surgery
Dept Of Surgery
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Surgical Anatomy
? Composed of a superficial part and a deep part.
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? Superficial part: lies in the submandibular trianglebetween two bellies of digastric muscle
? Deep part: lies below and lateral to the line of the
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submandibular duct, in the floor of the mouth, above and
deep to the mylohyoid.
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? Borders
? Lateral ? proximal half of the mandible.
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? Posterior ? anterior to but near the low anterior margin of theparotid gland.
? Inferior ? approaches the level of the hyoid bone.
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? Majority of gland lies over the external surface of the mylohyoid
muscle.
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? Lateral to and abuts the lingual and hypoglossal nerve and ismedial to the marginal mandibular and cervical branch of the
facial nerve.
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? Drains through Wharton's duct in anterior floor of the
mouth
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? Lymphatic Drainage Level IB--- Content provided by FirstRanker.com ---
Submandibular ganglion is attached to the nerve at this point andis also within the sheath of the gland
Submandibular duct lies beneath the lingual nerve as it emerges
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from the upper pole of the gland.
Lingual nerve lies first between the duct and the deep part of the
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gland, then crosses medially beneath the duct to ascend on thehyoglossus to supply the tongue.
In some subjects a posterior sublingual gland drains into the
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submandibular duct
Bartholin's major sublingual gland may drain via A single duct into
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the submandibular duct or by a separate openSalivary Gland Tumors
Epidemiology
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? Relatively uncommon ? 2% of head and neck neoplasms? Diverse histopathology
Distribution
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? Parotid: 80% overall; 80% benign; 25% malignant
?
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? Submandibular: 15% overall; 50% benign;43%malignant? Sublingual/Minor: 5% overall; 40% benign;65%malignant
? Preponderance of benign tumors in women
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? Malignant tumors exhibit an equal sex distribution
? Patients with benign tumors are younger (mean age: 46
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years) compared with those with malignant tumors (meanage: 54 years)
? Trend to an older age for submandibular and minor salivary
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gland locations
Risk factors
? Nutrition: low intake of vitamins
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? Smoking
? Irradiation
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? Ultraviolet exposure (controversial)Molecular targeting
Recent interest in molecular targeting of salivary gland
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malignancies
Molecular markers
? EGFR
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Overexpression in all histologic subtypes
? HER2
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Ductal carcinoma? C-kit
Adenoid cystic
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Although there is overexpression of these molecular markers, the
rates of true genetic mutation is much lower
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Clinical Presentation
? Painless, rapidly enlarging mass
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? Indolent period >10 years? Pain is more frequently associated with malignant
disease
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Clinical features suggesting a malignant tumour:
? Rapid growth rate
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? Pain? Facial nerve palsy
? Childhood occurrence
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? Skin involvement
? Cervical adenopathy
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WHO classification of salivary gland tumorsMorphology
? Pleomorphic adenomas:
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originate from the intercalated duct cells and myoepithelialcells
? Oncocytic tumors:
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originate from the striated duct cells
? Acinic cell tumors:
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originate from the acinar cells? Mucoepidermoid & squamous cell carcinomas:
develop in the excretory duct cells.
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Diagnostic Work-Up
? History /Physical Examination
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? Computed tomography (CT) scans? Magnetic resonance imaging (MRI)
(T1-weighted images are excellent to assess the margins, deep extent,
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and patterns of infiltration because the (fatty) background of the gland is
hyperintensive)
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Perineural invasion may be evaluated with both CT and MRI? PET CT Scan
Potential role for staging and management in salivary gland carcinomas
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? Fine-needle aspiration cytology
Axial CT scan showing left submandibular gland lesion
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MRI scan showing right submandibular gland lesion
PET CT scan showing right submandibular gland lesion
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Treatment
? Surgery
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? Radiotherapy? Chemotherapy (not efficacious)
Surgery
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? Mainstay of treatment? Submandibular Gland excision with level Ib dissection
recommended
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? Radical resection is indicated with tumors that invade the
mandible, tongue, or floor of mouth
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Submandibular Triangle Dissection? Scalpel proceeds through the skin in a curvilinear incision from
just off the midline anteriorly to just below the earlobe posteriorly
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? Flap is elevated deep to platysma muscle
? Surgeon must be aware of the course of the marginal branch of
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the facial nerve.? It is important to identify this nerve and mobilize it anteriorly and
posteriorly.
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Incision site for submandibular triangle
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dissectionIncision for combined neck dissection
Skin flap raised superiorly with platysma muscle left in place
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Skin flap raised superiorly with platysma muscle
Marginal branch of the facial nerve and its
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relationship with the facial vessels--- Content provided by FirstRanker.com ---
Detail of the submandibular triangle with the submaxil ary gland resectedManagement of Neck
Management of the N0 neck
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? Tumors >4cm? High grade histology
Management of the N+ neck
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? Ipsilateral MRND for clinically or radiographically positive
nodes
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? Incidence of multilevel node involvementPostoperative Radiotherapy
Indications
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? T3-4 tumors? Close or positive margin
? Incomplete resection
? Bone involvement
? Perineural invasion
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? Positive nodes? Recurrent cancer
Prognosis
? Survival of patients with submandibular cancers is inferior
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to that of parotid cancers
? Perineural invasion: independent prognostic factor for
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distant metastases or DFS? Impairment of function of the facial nerve : poor DFS
? Acinic cell and (low-grade)mucoepidermoid cancer: best
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prognosis
? Undifferentiated & squamous cell cancer: worst prognosis
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