PAROTID TUMOR

PAROTID TUMORAKBAR FAUZIIntroductionThere are three major salivary glands in human body, parotid gland, submandibular gland and sublingual gland and the largest is parotid glandSalivary gland neoplasms represent 57% of all head and neck tumors. Among salivary gland neoplasms, 80% arise in the parotid gland, from which 80% is benign. Pleomorphic adenoma is the most common tumor of parotid gland and represents 60% of all parotid neoplasmSubmandibular: 15% overall; 50% benignSublingual/Minor: 5% overall; 40% benignDefinitionParotid tumors are relatively rare neoplasms that present as an enlarging mass beneath the skin of the cheekAnatomiThe parotid gland is the largest of the major salivary glands. It arises as an epithelial proliferation from the lining of the oral cavity at 5 weeks postovulationThe facial nerve (cranial nerve VII) divides the gland into the larger superficial and smaller deep component. Though these are commonly referred to as the superficial and deep lobes, they are not true lobesIncidence and etiologybenign tumors of the parotid gland are more likely to occur in women than in menThe median age for occurrence of these tumors is in the fifth decade of lifeParotid tumors occur most commonly in CaucasiansEtiology unknown

ClassificationTumor Parotid

BENIGNMALIGNAPleomorfic adenona- Basal cell carsinomaWarthin Tumor - Mucoepidermoid carcinomaOncocytoma- Adenoid cystic carsinomaMyoepithelioma- AdenocarsinomaMonomorphic adenoma- CarsinosarcomaBasal cell adenoma- Acistic cell carsinomaCanalicular adenoma- Squamous Cell carsinoma- Clear cell carsinoma- Epithelial-myoepithelial carsinoma

Pleomorfic adenoma

American Join Committee On Cancer TMN Clinical Classification Of Major Salivary Gland TumorsPrimary Tumor (T) Tx : Primary tumor cannot be assessed T0 : No evidence of primary Tumor T1 : Tumor 2 cm in greatest dimension without extraparenchymal extension T2 : Tumor > 2 cm but 4 cm in greatest dimension without extraparencymal extension T3 : Tumor having Extraparenchymal extension without seventh nerve inolement and?or > 4 cm but 6 cm in greatest dimension T4 : Tumor invades base of skull, seventh nerve and/or > 6 cm in greatest dimensionRegional Lymph Nodes (N) Nx : Regional lymph nodes cant be assessed N0 : No regional lymph node metastasis N1 : Metastasis in a single ipsilateral lymph node, 3 cm in greatest dimension N2 : Metastasis in a single ipsilateral lymph node, > 3 cm but 6 cm in greatest dimension ; or in multiple ipsilateral lymph nodes, none > 6 cm in greatest dimension ; or in bilateral or contralateral lymph nodes, none > 6 cm in greatest dimension N2a : Metastasis in a single ipsilateral lymph node > 3 cm but 6 cm in greatest dimension N2b : Metastasiss in multiple ipsilateral lymph nodes, none > 6 cm in greatest dimension N2c : Metastasis in bilateral or contralaeral lymph nodes, none > 6 cm in greatest dimension N3 : Metastasis in lymph node > 6 cm in greatest dimensionDistant Metastasis

Mx : Distant metastasis cant be assessed M0 : No distant metastasis M1 : Distant MetastasisAmerican Joint Committee On Cancer Staging System For Major Salivary Gland TumorsStageTNMStage 1T1, T2N0M0Stage IIT3N0M0Stage IIIT1, T2N1M0Stage IVT4T3, T4Any TAny TN0N1N2, N3Any NM0M0M0M1CLINICAL EVALUATIONBENIGNMALIGNAgrow slowly and without painDeep-lobe parotid tumors may grow silently deep to the lower jaw (mandible)Facial or jaw pain, facial twitching or weakness, pain with chewing (trismus), or spread to lymph nodes in the neck or to other regions (lung, liver, brain)INVESTIGATIONSRadiologicCT-ScanMRIFine needle aspiration biopsyBENIGN PAROTID TUMORpleomorfic adenoma

Most common of all salivary gland neoplasms70% of parotid tumors50% of submandibular tumors45% of minor salivary gland tumors6% of sublingual tumors4th-6thdecadesF:M = 3-4:1

Gross pathologySmooth- Well-demarcatedSolidCystic changesMyxoid stroma

HistologyMixture of epithelial, myopeithelial and stromal componentsEpithelial cells: nests, sheets, ducts, trabeculaeStroma: myxoid, chrondroid, fibroid, osteoidNo true capsuleTumor pseudopods

Treatment: complete surgical excisionParotidectomy with facial nerve preservation- Avoid enucleation and tumor spill

Warthins Tumorpapillary cystadenoma lymphomatosum6-10% of parotid neoplasmsOlder, Caucasian, males10% bilateral or multicentric3% with associated neoplasmsPresentation: slow-growing, painless massHistologyPapillary projections into cystic spaces surrounded by lymphoid stromaEpithelium: double cell layerLuminal cellsBasal cellsStroma: mature lymphoid follicles with germinal centers

OncocytomaRare: 2.3% of benign salivary tumors6th decadeM:F = 1:1Parotid : 78%MalignaMucoepidermoid CarcinomaMost common salivary gland malignancy5-9% of salivary neoplasmsParotid 45-70% of cases3rd-8th decades, peak in 5th decadeF>MCaucasian > African AmericanMucoepidermoid CarcinomaPresentationLow-grade: slow growing, painless massHigh-grade: rapidly enlarging, +/- pain

Mucoepidermoid CarcinomaGross pathologyWell-circumscribed to partially encapsulated to unencapsulatedSolid tumor with cystic spaces

Mucoepidermoid CarcinomaHistologyLow-gradeMucus cell > epidermoid cellsProminent cystsMature cellular elements

Mucoepidermoid CarcinomaHistologyIntermediate- gradeMucus = epidermoidFewer and smaller cystsIncreasing pleomorphism and mitotic figures

Mucoepidermoid CarcinomaHistologyHigh-gradeEpidermoid > mucusSolid tumor cell proliferationMistaken for SCCAMucin staining

Mucoepidermoid CarcinomaTreatmentInfluenced by site, stage, gradeStage I & IIWide local excisionStage III & IVRadical excision+/- neck dissection+/- postoperative radiation therapyAcinic Cell Carcinoma2nd most common parotid and pediatric malignancy5th decadeF>MBilateral parotid disease in 3%PresentationSolitary, slow-growing, often painless mass

Acinic Cell CarcinomaGross pathologyWell-demarcatedMost often homogeneous

Acinic Cell CarcinomaHistologySolid and microcystic patternsMost common Solid sheetsNumerous small cystsPolyhedral cellsSmall, dark, eccentric nucleiBasophilic granular cytoplasm

Acinic Cell CarcinomaTreatmentComplete local excisionPrognosis5-year survival: 82%10-year survival: 68%25-year survival: 50%AdenocarcinomaRare5th to 8th decadesF > MParotid and minor salivary glandsPresentation:Enlarging mass25% with pain or facial weakness

AdenocarcinomaHistologyHeterogeneityPresence of glandular structures and absence of epidermoid componentGrade IGrade IIGrade III

AdenocarcinomaTreatmentComplete local excisionNeck dissectionPostoperative XRTPrognosisLocal recurrence: 51%Regional metastasis: 27%Distant metastasis: 26%15-year cure rate:Stage I = 67%Stage II = 35%Stage III = 8%

HATUR NUHUN