SALIVARY GLAND TUMORS surgery presentation..

salivary gland tumors

1. SALIVARY GLAND TUMORS By ; MODERATOR; Dr Navdeep Dr Mukul Sharma Junior resident Assistant Professor

2. INTRODUCTION The parotid,submandibular and sublingual glands are the three paired major salivary glands The minor salivary glands are multiple and situated mainly in lips ,buccal mucosa,tongue and palate[>800] The glandular architecture is essentially a series of ducts that open into oral cavity and surrounded by acini,which produce saliva

3. ANATOMY The parotid represents the largest of the salivary glands and is situated in front of external acoustic meatus between the ramus ofcthe mandible and sternocleidomastoid . The Submandibular glands are present in floor of mouth ,they lie in the submandibular space between the digastric muscle and extend upwards deep to the mandible The sublingual glands contribute 5% of saliva production and are smallest of the major salivary glands ,they lie above the mylohyoid muscle and below the floor of mouth and bordered laterally by mandible .

4. The major duct of parotid is stensons duct which opens into vestibule of mouth opposite the crown of upper second molar tooth The submandibular duct is whartons duct which opens into floor of mouth paramedian to frenulum Sublingual glands secretion are drained by small ducts [ rivinus ducts]that exit the sublingual fold at floor of mouth

5. EPIDEMIOLOGY Primary salivary gland neoplasms are extremely rare and form less than 3% of head and neck malignancies The incidence is 0.4-13.5 cases per 100 000 for benign neoplasms and 0.4 -2.6 per 100 000 for malignant tumors Most salivary gland tumors [>80%]occur in major salivary glands and majority of them are benign . Minor salivary gland tumors are more likely to be malignant [>50%] The commonest benign neoplasm is pleomorphic adenoma [mostly seen in parotid], while commonest malignant tumor is mucoepidermoid carcinoma.

6. Etiology Smoking, Viral infections, - EBV,CMV,Polyoma virus Radiation exposure, Environmental factors and industrial exposure, - rubber manufacturing, - nickel compounds - hair dyes

7. Pleomorphic Adenoma These are the most common benign salivary gland tumors Most common between third and sixth decade and are more frequently seen in women Most frequently occur in parotid glands [>80%] Presents as painless,well defined ,mobile mass with gradual progression HPE – The tumor comprises mixed epithelial,myoepithelial and stromal components .A variety of cells including oval,epitheloid,spindle,plasmacytoid and clear cells in variable amount of myxoid to chondroid to hyalinized stroma Sudden increase in size,atypia,diffuse fibrosis and necrosis should be evaluated to rule out malignancy which is rare IHC-luminal cells express CK7 and myoepithelial cells express p63,s-100,SMA

8. Warthins Tumor Also known as adenolymphoma or cystadenoma lymphomatosum Second most common benign salivary gland tumor[5-15%] ,seen in older men ,sixth decade of life These are strongly associated with cigarette smoking and radiation exposure .They are almost exclusively seen in parotid gland Clinically they present as painless ,slow growing swellings .Malignant transformation is extremely rare [<1%] HPE- composed of oncocytic epithelial cells lining ductal ,papillary and cystic spaces in a reactive lymphoid tissue .On microscopy they have papillary and cystic structures lined by bilayered oncocytic epithelial cells in lymphoid stroma with germinal centres

9. Mucoepidermoid Carcinoma They are most common salivary gland malignancies in children and young adult with peak incidence in second decade of life They are known to occue following radiation or chemotherapy in childhood .They occur both in major and minor salivary glands with parotid being the most common site Clinically they present as soft to firm painless masses with gradual increase in size HPE-low grade mucoepidermoid carcinoma are generally cystic ,well circumscribed,rich in mucus cells.Intermediate grade tumors are less circumscribed and more solid .High grade are solid and show nuclear atypia ,perineural invasion and lymphovascular emboli. High grade tend to be locally aggressive with bone and skin involvement and nodal metastases.Distant metastasis are seen mainly to lungs

10. Other Malignant Tumors Adenoid cystic carcinoma : slow growing malignancy,high prelidiction for perineural invasion,mostly occur in major salivary glands ,may present as slow growing masses with pain or numbness,facial nerve palsy,nodal metastases or asymptomatic distant metastases especially lungs .HPE – unencapsulated,variable proportions of epithelial and myoepithelial cells showing cribriform tubular and solid patterns, perineural invasion widely seen .IHC positive for c-KIT,SMA Carcinoma ex pleomorphic adenoma: arises in association with primary or recurrent pleomorphic adenoma ,often presents as rapid growing swelling with pain and facial palsy .HPE shows variable proportions of pleomorphic adenoma and high grade adenocarcinoma

11. Salivary duct carcinoma : high grade adenocarcinoma resembling high grade mammary ductal carcinoma . It is less common,mostly arises from parotid,present as aggressive rapidly growing mass with facial palsy,pain and cervical lymphadenopathy .HPE-resembles high grade invasive ductal breast cancer with large duct like configuration with comedo necrosis and cribriform and roman bridge like features .Also shows androgen receptor and HER2 receptor positivity

12. INVESTIGATIONS Imaging; ultrasonography-benign tumors like pleomorphic adenoma are generally visualised as well lobulated hypoechoic lesions with some calcifications,malignant tumors have irregular shapes with blurred margins CT/MRI-best tools for complete imaging of salivary glands .In most cases CT scans are considered superior for differentiating neoplasms from inflammatory conditions while MRI gives better differentiation between benign and malignant neoplasms . PET-CT –salivary glands are involved as the site of metastasis with an unknown primary

13. CYTOLOGY The Milan system for reporting salivary gland cytopathology is effective tool to asses adequacy ofcytopathology specimen and quantify the risk of malignancy

14. Staging for salivary gland malignancies

15. TREATMENT Surgery – the extent of resection is determined size,stage and grade of differentiation Elective neck dissection should be offered for T3/T4 and high grade tumors In node positive disease comprehensive neck dissection is mandatory Adjuvant radiotherapy is advocated for stage III and IV tumors ,high grade of differentiation as well as presence of high risk features such as positive margins ,presence of perineural invasion or lymphovascular invasion and nodal metastases with extranodal extension The role of chemoradiation in adjuvant setting is still investigation

16. PAROTIDECTOMY PAROTID ANATYOMICAL EXTENT:PAROTID ENCAPSULATES VESSELS NERVES AND LYMPH NODES WITH IN ITS CAPSULE FUSING WIDELY WITH INVESTING FASCIA FROM TEMPORALIS ABOVE TO DIAGASTRIC BELOW FROM BUCCINATOR ANTERIORLY TO MASTOID POSTERIORLY TYPES: 1.EXTRACAPSULAR DISSECTION 2.ADEQUATE PAROTIDECTOMY 3.SUPERFICIAL PAROTIDECTOMY 4.TOTAL CONSERVATIVE PAROTIDECTOMY 5.RADICAL PAROTIDECTOMY

17. Extracapsular tumor dissection does not require facial nerve dissection this reduces incidence of facial nerve palsy Adequate parotidectomy involves removal of tumor with cuff of normal tissue ,especially in tail of parotid lesions ,may not be possible in all cases Total conservative parotidectomy in tumor straddling the superficial and deep lobe across pateys plane following removal of superficial lobe,the deep lobe is dissected off the temporal veins and terminal branches of external carotid artery .This result in complete removal of suprafacial and subfacial parotid gland with preservation of facial nerves

18. Radical parotidectomy with extraparenchymal spread and facial nerve invasion ,involved structures are removed .It involves removal of all parotid gland tissue and elective division of all facial nerve branches as well as structures involved most commonly the masseter muscle

19. Incision-the blair incision is straight preauricular incision curving slightly below the ear lobule The lazy s incision has three components ;horizontal part along skin crease two finger breadth from angle of mandible,vertical part close to tragus ,communicating part connecting horizontal and vertical component in a curve Face lift incision with anterior preauricular incision similar to blair while posterior curves at right angle reaching hairline

20. Facial nerve localization Most important steps in parotidectomy Usually identified by anterograde technique using anatomical landmarks TRAGAL POINTER – lies 1cm deep and inferior to tip of tragal cartilage DIGASTRIC MUSCLE – can be identified above the upper border of posterior belly of digastric TYMPANOMASTOID SUTURE – lies inferior to suture line as kit overlies stylomastoid foramen

21. Complications Some of the most significant complications of parotidectomy; Transection of facial nerve and permanent facial weakness Permanent numbness of ear lobe associated with great auricular nerve transection Freys syndrome

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