<img src="oral_pathology_module.jpg"> </img> **Oral Pathology module** **Salivary gland diseases** **DENT4217** **A/Prof Omar Kujan** **BDS DipOPath MDSc MFDS RCPS FHEA FRCPath PhD** # **Oral Pathology module** # **Salivary gland diseases** ## **DENT4217** THE UNIVERSITY OF WESTERN AUSTRALIA Acknowledgement of country The University of Western Australia acknowledges that its campus is situated on Noongar land, and that Noongar people remain the spiritual and cultural custodians of their land, and continue to practise their values, languages, beliefs and knowledge. Artist: **Dr Richard Barry Walley OAM** # **Acknowledgement of country** The University of Western Australia acknowledges that its campus is situated on Noongar land, and that Noongar people remain the spiritual and cultural custodians of their land, and continue to practise their values, languages, beliefs and knowledge. Artist: **Dr Richard Barry Walley OAM** **Learning outcomes** 1. Learn salivary gland disorders, benign and malignant neoplasms # **Learning outcomes** 1. Learn salivary gland disorders, benign and malignant neoplasms **CLASSIFICATION OF SALIVARY GLAND** **DISEASES** **A.DEVELOPMENTAL** * Congenital aplasia/agenesis * Congenital hypoplasia * Atresia * Aberrance / ectopic gland * Diverticuli * Accessory duct * Congenital fistula # **CLASSIFICATION OF SALIVARY GLAND DISEASES** ## **A. DEVELOPMENTAL** - Congenital aplasia/agenesis - Congenital hypoplasia - Atresia - Aberrance / ectopic gland - Diverticuli - Accessory duct - Congenital fistula > [!info] Anatomical Reminder > The lecture emphasizes the importance of understanding the anatomy and histology of both major salivary glands (Parotid, Submandibular, Sublingual) and minor salivary glands (600-1,000 distributed throughout the oral cavity). **B.INFLAMMATORY** * **ACUTE OR CHRONIC** STAPHYLOCOCCAL STREPTOCOCCAL ACTINOMYCOSIS TUBERCULOSIS * **VIRAL INFECTION** MUMPS CYTOMEGALO VIRUS INFECTION PARAINFLUENZA * **SARCOIDOSIS** * **MELKERSON-ROSENTHAL SYNDROME** * **ALLERGY** * **SALIVARY FISTULA** * **POST IRRADIATION TO ORAL TUMOUR** ## **B. INFLAMMATORY** - **ACUTE OR CHRONIC** - STAPHYLOCOCCAL - STREPTOCOCCAL - ACTINOMYCOSIS - TUBERCULOSIS - **VIRAL INFECTION** - MUMPS - CYTOMEGALO VIRUS INFECTION - PARAINFLUENZA - **SARCOIDOSIS** - **MELKERSON-ROSENTHAL SYNDROME** - **ALLERGY** - **SALIVARY FISTULA** - **POST IRRADIATION TO ORAL TUMOUR > [!warning] Post-Radiation Sialadenitis > Radiation therapy for head and neck cancer causes significant salivary gland damage, leading to severe dysfunction and xerostomia. ** **C.SIALOLITHIASIS** • DUE TO STRICTURE OF DUCT • DUE TO TRAUMA OR INFECTION • DUE TO SALIVARY STONE • MUCOUS PLUG **D.CYSTS** • MUCOCELE • RANULA • LYMPHO EPITHELIAL CYST • BRANCHIAL CYST **E. F.SIALADENOSIS** **G.SJOGRENS SYNDROME** ## **C. SIALOLITHIASIS** - DUE TO STRICTURE OF DUCT - DUE TO TRAUMA OR INFECTION - DUE TO SALIVARY STONE - MUCOUS PLUG ## **D. CYSTS** - MUCOCELE - RANULA - LYMPHO EPITHELIAL CYST - ==Commonly seen on the posterior side of the tongue.== - BRANCHIAL CYST ## **E. F. SIALADENOSIS** ## **G. SJOGRENS SYNDROME** **I.NEOPLASMS** **BENIGN EPITHELIAL** • ADENOMA • ONCOCYTOMA • WARTHINS TUMOUR • PLEOMORPHIC ADENOMA **MALIGNANT EPITHELIAL** • ADENOCARCINOMA • MUCOEPIDERMOID CARCINOMA • ADENOCYSTIC CARCINOMA • ACINIC CELL CARCINOMA • MALIGNANT PLEOMORPHIC ADENOMA ## **I. NEOPLASMS > [!note] > Salivary gland tumors are relatively uncommon but are challenging to diagnose and manage. The WHO classification is extensive, with the 2022 version listing 38 different entities. ** ### **BENIGN EPITHELIAL** - ADENOMA - ONCOCYTOMA - WARTHINS TUMOUR - PLEOMORPHIC ADENOMA ### **MALIGNANT EPITHELIAL** - ADENOCARCINOMA - MUCOEPIDERMOID CARCINOMA - ADENOCYSTIC CARCINOMA - ACINIC CELL CARCINOMA - MALIGNANT PLEOMORPHIC ADENOMA - **BENIGN MESENCHYMAL** HEMANGIOMA LYMPHANGIOMA NEUROFIBROMA SCHWANNOMA LIPOMA - **MALIGNANT MESENCHYMAL** RHABDOMYOSARCOMA HEMANGIOENDOTHELIOMA - **OTHERS** LYMPHOMA-HODGKINS & NON HODGKINS METASTATIC ### **BENIGN MESENCHYMAL** - HEMANGIOMA - LYMPHANGIOMA - NEUROFIBROMA - SCHWANNOMA - LIPOMA ### **MALIGNANT MESENCHYMAL** - RHABDOMYOSARCOMA - HEMANGIOENDOTHELIOMA ### **OTHERS** - LYMPHOMA-HODGKINS & NON HODGKINS - METASTATIC **Sialolithiasis (Salivary Stones)** •Sialoliths are calcified and organic matter that form within the secretory system of the major salivary glands. The etiology of sialolith formation is still unknown; •however, several factors contribute to stone formation. Inflammation, irregularities in the duct system, local irritants, and anti-cholinergic medications may cause pooling of saliva within the duct, which is thought to promote stone formation. •It is believed that a nidus of salivary organic material becomes calcified and gradually forms a sialolith. •**The submandibular gland is the most common site of involvement, and 80 to 90% of sialoliths occur in this gland.** # **Sialolithiasis (Salivary Stones)** - Sialoliths are calcified and organic matter that form within the secretory system of the major salivary glands. The etiology of sialolith formation is still unknown; however, several factors contribute to stone formation. Inflammation, irregularities in the duct system, local irritants, and anti-cholinergic medications may cause pooling of saliva within the duct, which is thought to promote stone formation. > [!info] Etiology > Formation requires a central nidus or core (e.g., a cell or mucus plug) around which calcium salts can deposit in layers. Systemic conditions can contribute to their formation. - It is believed that a nidus of salivary organic material becomes calcified and gradually forms a sialolith. - **The submandibular gland is the most common site of involvement, and 80 to 90% of sialoliths occur in this gland.** - **==Diagnosis:==** ==Imaging, such as a **sialogram**, is used to visualize the gland's ductal system and identify blockages.== - **==Clinical Presentation:==** ==Can sometimes be palpated as a yellowish, firm, hard swelling within the duct.== - **==Histopathology:==** ==The ductal epithelium may undergo **metaplasia** as an adaptive response to the chronic irritation and blockage.== - **==Treatment:==** ==Small, accessible stones can be removed with a simple incision. Deeper stones or extensive gland damage often require surgical removal of the entire gland (**sialadenectomy**).== A sialogram showing an uncalcified sialolithiasis in Wharton's duct. **B2B** **THE UNIVERSITY OF** **WESTERN** **AUSTRALIA** **A)** Lamellated calculi were found within the lumen of a dilated minor salivary duct **B)** Squamous metaplasia of the excretory ductal epithelium and exfoliated epithelium were observed in the minor salivary glands 11 - **A)** Lamellated calculi were found within the lumen of a dilated minor salivary duct - **B)** Squamous metaplasia of the excretory ductal epithelium and exfoliated epithelium were observed in the minor salivary glands **Mucocele** "Mucocele" is a clinical term that describes swelling caused by obstructed minor salivary gland duct. Mucoceles are classified as 1. Extravasation 2. Retention types. 3. A large form of mucocele located in the floor of the mouth is known as a RANULA. **Clinical Presentation** Extravasation mucoceles most frequently occur on the lower lip, where trauma is common. Buccal mucosa, tongue, floor of the mouth, and retro molar region are other commonly traumatized areas where mucous extravasation may be found. Mucous retention cysts are more commonly located on the palate or the floor of the mouth. # **Mucocele** "Mucocele" is a clinical term that describes swelling caused by obstructed minor salivary gland duct. Mucoceles are classified as 1. Extravasation 2. Retention types. 3. A large form of mucocele located in the floor of the mouth is known as a RANULA. ## **Clinical Presentation** Extravasation mucoceles most frequently occur on the lower lip, where trauma is common. Buccal mucosa, tongue, floor of the mouth, and retro molar region are other commonly traumatized areas where mucous extravasation may be found. Mucous retention cysts are more commonly located on the palate or the floor of the mouth. - ==Appears as a soft, bluish, dome-shaped swelling.== - ==The size can fluctuate; it may shrink as the body's inflammatory cells process the pooled mucin and then enlarge again as more saliva accumulates.== - ==If it ruptures, a clear, viscous fluid (saliva) is released.== **Mucous extravasation cyst** Epithelioid macrophages forming a pseudocyst around the extravasated mucin, no true epithelium is present. 13 ## **Mucous extravasation cyst** Epithelioid macrophages forming a pseudocyst around the extravasated mucin, no true epithelium is present. > [!abstract] Pathogenesis of Extravasation Cysts > - **Cause:** Trauma (e.g., lip or cheek biting) ruptures a salivary duct, causing saliva to spill into the surrounding connective tissue. > - **Response:** The spilled mucin acts as a foreign material, triggering an inflammatory response. A wall of **granulation tissue** containing phagocytes (macrophages) forms around the mucin. > - **Histopathology:** It is a **pseudocyst** because it lacks a true epithelial lining. Instead, it is lined by granulation tissue and inflammatory cells. > - **Treatment:** Surgical excision is required. It is crucial to remove the associated, damaged minor salivary glands to prevent recurrence. > [!info] Mucous Retention Cyst > This is a less common type where the cyst forms *within* the duct itself due to an obstruction, leading to ductal dilation. It is a true cyst with an epithelial lining. **XEROSTOMIA** **CAUSES OF XEROSTOMIA-** 1. **TEMPORARY**-psychological (anxiety), duct calculi, sialoadenitis, drug therapy( anticholinergic, sympathomimetic, etc.) 2. **PERMANENT-** Salivary gland aplasia, sjogrens syndrome, following radio therapy, surgical desalivation 14 # **XEROSTOMIA** ## **CAUSES OF XEROSTOMIA-** 1. **TEMPORARY**-psychological (anxiety), duct calculi, sialoadenitis, drug therapy( anticholinergic, sympathomimetic, etc.) 2. **PERMANENT-** - Salivary gland aplasia, sjogrens syndrome, following radio therapy, surgical desalivation > [!info] > Permanent xerostomia is caused by irreversible destruction of the salivary gland parenchyma (the saliva-producing tissue), which is replaced by fibrous or adipose tissue. **XEROSTOMIA** THE UNIVERSITY OF WESTERN AUSTRALIA Common Especially in middle to late life USA: 17% of 65-84 year olds had symptoms of oral dryness Europe: 29% of persons in a may have symptoms of dry mouth BUT little correlation with objective measurements 15 - Common - Especially in middle to late life - USA: 17% of 65-84 year olds had symptoms of oral dryness - Europe: 29% of persons in a may have symptoms of dry mouth BUT little correlation with objective measurements > [!note] > In Australia, it is estimated to affect around 20% of the population, with rates as high as 80% in patients over 65. **XEROSTOMIA** THE UNIVERSITY OF WESTERN AUSTRALIA Common Drugs Radiotherapy to head and neck Sjogren's syndrome Psychogenic? HCV disease? HIV disease? Uncommon Chronic graft versus host disease Sarcoidosis Cystic fibrosis Diabetes mellitus Amyloidosis Haemochromatosis Wegener's disease Salivary gland agenesis Triple A syndrome Cholinergic dysautonomia Others 16 ## **Causes** ### **Common** - Drugs - Radiotherapy to head and neck > [!question] Does xerostomia from radiation get better? > It may improve slightly over time, but significant recovery of function is unlikely. - Sjogren's syndrome - Psychogenic? - HCV disease? - HIV disease? ### **Uncommon** - Chronic graft versus host disease - Sarcoidosis - Cystic fibrosis - Diabetes mellitus - Amyloidosis - Haemochromatosis - Wegener's disease - Salivary gland agenesis - Triple A syndrome - Cholinergic dysautonomia - Others **XEROSTOMIA** THE UNIVERSITY OF WESTERN AUSTRALIA Dysarthria Dysphagia Mucosal adhesion "Stringy saliva" Caries A series of images showing symptoms of xerostomia. ## **Clinical Features** - Dysarthria - Dysphagia - Mucosal adhesion - "Stringy saliva" - Caries A series of images showing symptoms of xerostomia. - ==A **glossy, atrophic appearance of the tongue**.== - ==The dental mirror sticking to the buccal mucosa is a classic sign.== - ==Increased risk of **dental caries**, particularly **cervical caries**.== - ==Increased susceptibility to oral infections, especially **candidiasis**.== **Discrete swelling in gland** **THE UNIVERSITY OF** **WESTERN** **AUSTRALIA** * Define location – clinical, imaging MRI – is it in the gland? * Exclude infectious causes * Fine needle aspiration * Excisional biopsy if thought benign * Incisional biopsy if thought malignant # **Discrete swelling in gland** - Define location – clinical, imaging MRI – is it in the gland? - Exclude infectious causes - Fine needle aspiration - Excisional biopsy if thought benign - Incisional biopsy if thought malignant **Discrete swelling in gland** * Define location – clinical, imaging MRI – is it in the gland? * Exclude infectious causes * Fine needle aspiration * Excisional biopsy if thought benign * Incisional biopsy if thought malignant **Classification of salivary tumours** **Benign:** Pleomorphic adenoma Warthin's tumour **Malignant:** Mucoepidermoid carcinoma Polymorphous low-grade adenocarcinoma Adenoid cystic carcinoma Carcinoma ex pleomorphic adenoma # **Classification of salivary tumours** ## **Benign:** - Pleomorphic adenoma - Warthin's tumour ## **Malignant:** - Mucoepidermoid carcinoma - Polymorphous low-grade adenocarcinoma - Adenoid cystic carcinoma - Carcinoma ex pleomorphic adenoma **Site prevalence of salivary neoplasms** Parotid probably benign (85%) Submandibular probably benign (70%) Minor glands palate 45% malignant sublingual almost certainly malignant What features suggest malignancy? # **Site prevalence of salivary neoplasms** - **Parotid** - probably benign (85%) - **Submandibular** - probably benign (70%) - **Minor glands** - palate 45% malignant - **sublingual** - almost certainly malignant > [!tip] Clinical Rule of Thumb > Any lump in a minor salivary gland, especially in the **upper lip**, should be considered suspicious for malignancy until proven otherwise. What features suggest malignancy? An image showing a growth inside someone's mouth. An image showing a growth inside someone's mouth. The University of Western Australia <html> <body> <table> <thead> <tr> <td>Benign</td> <td>Malignant</td> </tr> </thead> <tbody> <tr> <td>Circumscribed</td> <td>Poorly circumscribed</td> </tr> <tr> <td>Mobile</td> <td>Fixed</td> </tr> <tr> <td>Slow-growing</td> <td>Induration (difficult)</td> </tr> <tr> <td>Painless</td> <td>Ulceration</td> </tr> <tr> <td>Symptoms only cosmetic or pressure</td> <td>Pain</td> </tr> <tr> <td></td> <td>Metastasis</td> </tr> <tr> <td></td> <td>Nerve signs</td> </tr> <tr> <td></td> <td>Sometimes rapid growth</td> </tr> </tbody> </table> </body> </html> # **Distinguishing Benign vs. Malignant Tumours** <html> <body> <table> <thead> <tr> <td>Benign</td> <td>Malignant</td> </tr> </thead> <tbody> <tr> <td>Circumscribed</td> <td>Poorly circumscribed</td> </tr> <tr> <td>Mobile</td> <td>Fixed</td> </tr> <tr> <td>Slow-growing</td> <td>Induration (difficult)</td> </tr> <tr> <td>Painless</td> <td>Ulceration</td> </tr> <tr> <td>Symptoms only cosmetic or pressure</td> <td>Pain</td> </tr> <tr> <td></td> <td>Metastasis</td> </tr> <tr> <td></td> <td>Nerve signs</td> </tr> <tr> <td></td> <td>Sometimes rapid growth</td> </tr> </tbody> </table> </body> </html> > [!info] Key Distinctions > - **Nerve Signs:** The presence of numbness, paresthesia, or facial nerve palsy is a strong indicator of malignancy. > - **Fixation:** Malignant tumors are often fixed to adjacent structures, whereas benign tumors are mobile. > - **Capsule:** Benign tumors are typically encapsulated, while malignant ones are not. **Pleomorphic (salivary) adenoma** So-called ‘mixed tumour” Commonest salivary neoplasm Most in major glands but common in minor Benign (but may transform to malignancy) Encapsulated (but must **not** be enucleated) Painless, slow-growing # **Pleomorphic (salivary) adenoma** - So-called ‘mixed tumour” - Commonest salivary neoplasm - Most in major glands but common in minor - Benign (but may transform to malignancy) - Encapsulated (but must **not** be enucleated) - Painless, slow-growing > [!warning] Malignant Transformation > While benign, if left untreated for many years (e.g., >10 years), it can transform into a highly aggressive **Carcinoma ex Pleomorphic Adenoma**, which has a very poor prognosis (patients often die within 18 months). > [!info] Cellular Origin > Arises from two cell types: **intercalated duct cells** and **myoepithelial cells**. The term “mixed tumour” is now obsolete. **Clinical features** †Mean age – 40 yrs †Slight female predilection; 2:1 Incidence in major and minor salivary glands is 10:1, Appears as a painless, slowly growing, smooth surfaced, dome shaped, firm mass ## **Clinical features** - †Mean age – 40 yrs - †Slight female predilection; 2:1 - Incidence in major and minor salivary glands is 10:1, - Appears as a painless, slowly growing, smooth surfaced, dome shaped, firm mass A gross specimen with a ruler for scale. A gross specimen with a ruler for scale. A man with a large facial tumor. A man with a large facial tumor. <img > A white background with the logo of the UNIVERSITY OF WESTERN AUSTRALIA on the top left. On the right, text reads "encapsulated tumour with many ducts and prominent myxochondroid areas." Below this is a large, irregularly shaped image showing a tissue sample with varying shades of pink and purple, indicating cellular structures and possibly some ducts or spaces within it.</img> Ducts surrounded by myoepithelial cells that merge into hyalinized stroma. **THE UNIVERSITY OF** **WESTERN** **AUSTRALIA** Ducts surrounded by myoepithelial cells that merge into hyalinized stroma. THE UNIVERSITY OF WESTERN AUSTRALIA Myxochondroid areas within the stroma. Ducts with surrounding epithelioid myoepithelial cells that merge into myxoid stroma that contains spindled myoepithelial cells. - Myxochondroid areas within the stroma. - Ducts with surrounding epithelioid myoepithelial cells that merge into myxoid stroma that contains spindled myoepithelial cells. > [!abstract] Histopathology Summary > The tumor is **encapsulated** and shows a **pleomorphic (mixed) appearance** with three main components: > 1. **Epithelial Component:** Duct-like or sheet-like structures formed by cuboidal cells. > 2. **Myoepithelial Component:** Cells can be spindle-shaped or have a distinct **plasmacytoid** (plasma cell-like) appearance. > 3. **Stromal Component:** The supporting connective tissue is highly variable and can be **hyalinized** (glassy), **myxoid** (mucoid), or even form **cartilage** (chondroid stroma). Warthin's tumour ‘Adenolymphoma’ not a lymphoma!! Almost all in parotid gland Elderly patients Benign, mobile, firm to fluctuant Sometimes multiple Encapsulated neoplasm # **Warthin's tumour** - ‘Adenolymphoma’ not a lymphoma!! - Almost all in parotid gland - Elderly patients - Benign, mobile, firm to fluctuant - Sometimes multiple - Encapsulated neoplasm **Warthin's tumour** •Synonym: Papillary cystadenoma lymphomatosum •Site: Tail of parotid •Bilateral occurrence •Age: 6th –7th decade •Male predominance •Associated with smoking - **Synonym:** Papillary cystadenoma lymphomatosum - **Site:** Tail of parotid - Bilateral occurrence - **Age:** 6th –7th decade - Male predominance - Associated with smoking > [!info] Macroscopic Appearance > The cystic fluid is often thick, brown, and described as 'chocolate-like.' Clinical and histological images of Warthin’s tumour WESTERN AUSTRALIA •Varying proportions of papillary cystic structures lined by bilayered oncocytic epithelial cells and surrounded by a lymphoid stroma including germinal centers - Varying proportions of papillary cystic structures lined by bilayered oncocytic epithelial cells and surrounded by a lymphoid stroma including germinal centers > [!abstract] Histopathology Summary > The name **Papillary Cystadenoma Lymphomatosum** describes its key features: > - **Cystic Spaces:** Contains multiple cysts with **papillary projections**. > - **Epithelial Lining:** A characteristic **double layer of oncocytic epithelial cells**. > - **Lymphoid Stroma:** The stroma is densely packed with **lymphoid tissue**, often forming **germinal centers**. High power view showing papillary structures lined by bilayered oncocytic epithelial cells, surrounded by a lymphoid stroma **THE UNIVERSITY OF** **WESTERN** **AUSTRALIA** High power view showing papillary structures lined by bilayered oncocytic epithelial cells, surrounded by a lymphoid stroma The University of Western Australia **Mucoepidermoid carcinoma** * Most common * Site: Major & minor salivary glands * 2nd to 7th decade * Female predilection * *Site: Palate* * *Tuberosity* * *Retromolar region* * *Tongue* * *Floor of the mouth* * Asymptomatic swelling + pain + facial nerve palsy 36 # **Mucoepidermoid carcinoma** - Most common - **Site:** Major & minor salivary glands - 2nd to 7th decade - Female predilection - **Site:** - *Palate* - *Tuberosity* - *Retromolar region* - *Tongue* - *Floor of the mouth* - Asymptomatic swelling + pain + facial nerve palsy > [!abstract] Histopathology > The name reflects its three cellular components: > 1. **Muco- (Mucous cells):** Cells with cloudy, pale cytoplasm that produce mucin. > 2. **-epidermoid (Squamous cells):** Islands of cells resembling stratified squamous epithelium. > 3. **Intermediate cells:** Smaller, basaloid-type cells. > The tumor grows in a combination of solid sheets and cystic spaces. 1112/02 Mucoepidermoid carcinoma, low-grade 1112/02 Mucoepidermoid carcinoma, low-grade Histological section showing glandular structures within dense connective tissue indicative of a pathological mass or tumor **Adenoid cystic carcinoma** Infrequent but very important May arise in any salivary gland Vague presenting symptoms (eg ‘funny feeling’) Slow-growing but highly infiltrative Late diagnosis common Good 5-year prognosis, **very** poor 15-year # **Adenoid cystic carcinoma** - Infrequent but very important - May arise in any salivary gland - Vague presenting symptoms (eg ‘funny feeling’) - Slow-growing but highly infiltrative - Late diagnosis common - Good 5-year prognosis, **very** poor 15-year > [!danger] Hallmark Feature: Perineural Invasion > This tumor has a strong tendency for **perineural invasion** (invading along nerve sheaths), which explains the common symptoms of pain and paresthesia (numbness) and is associated with a poorer prognosis. Adenoid cystic carcinoma •Synonym: Cylindroma •Site: Minor salivary gland •Mid aged adults, 5th –7th decade •Slow growing swelling •Swelling + dull ache + facial nerve paralysis •Late metastasis •Prognosis : Worse •Complications : CNS involvement 40 - **Synonym:** Cylindroma - **Site:** Minor salivary gland - **Age:** Mid aged adults, 5th –7th decade - Slow growing swelling - Swelling + dull ache + facial nerve paralysis - Late metastasis - **Prognosis:** Worse - **Complications:** - CNS involvement Intraoral image showing posterior teeth with dental amalgam restorations and adjacent mucosal tissue displaying a raised, red lesion. **Adenoid cystic** **carcinoma** # **Adenoid cystic carcinoma** > [!abstract] Histopathology > - Composed of small, dark-staining **basaloid cells**. > - The cells arrange in various patterns, with the most classic being the **cribriform ('Swiss cheese') pattern**, featuring multiple small, punched-out cystic spaces. > - **Perineural Invasion:** Tumor cells can be seen surrounding and infiltrating nerve bundles, which is a key diagnostic feature. **Questions** 43 A cartoon illustration depicting several people (possibly students) dealing with a swarm of angry red jellyfish-like creatures. Some people are holding megaphones, while one person holds a broom, and another holds a blue object. The top right of the image says "ENTER HERE!". # **Questions** [[L13 SalivaryGlandDiseases.pdf#page=1|L13 SalivaryGlandDiseases, p.1]] [[L13 SalivaryGlandDiseases.pdf#page=2|L13 SalivaryGlandDiseases, p.2]] [[L13 SalivaryGlandDiseases.pdf#page=3|L13 SalivaryGlandDiseases, p.3]] [[L13 SalivaryGlandDiseases.pdf#page=4|L13 SalivaryGlandDiseases, p.4]] [[L13 SalivaryGlandDiseases.pdf#page=5|L13 SalivaryGlandDiseases, p.5]] [[L13 SalivaryGlandDiseases.pdf#page=6|L13 SalivaryGlandDiseases, p.6]] [[L13 SalivaryGlandDiseases.pdf#page=7|L13 SalivaryGlandDiseases, p.7]] [[L13 SalivaryGlandDiseases.pdf#page=8|L13 SalivaryGlandDiseases, p.8]] [[L13 SalivaryGlandDiseases.pdf#page=9|L13 SalivaryGlandDiseases, p.9]] [[L13 SalivaryGlandDiseases.pdf#page=10|L13 SalivaryGlandDiseases, p.10]] [[L13 SalivaryGlandDiseases.pdf#page=11|L13 SalivaryGlandDiseases, p.11]] [[L13 SalivaryGlandDiseases.pdf#page=12|L13 SalivaryGlandDiseases, p.12]] [[L13 SalivaryGlandDiseases.pdf#page=13|L13 SalivaryGlandDiseases, p.13]] [[L13 SalivaryGlandDiseases.pdf#page=14|L13 SalivaryGlandDiseases, p.14]] [[L13 SalivaryGlandDiseases.pdf#page=15|L13 SalivaryGlandDiseases, p.15]] [[L13 SalivaryGlandDiseases.pdf#page=16|L13 SalivaryGlandDiseases, p.16]] [[L13 SalivaryGlandDiseases.pdf#page=17|L13 SalivaryGlandDiseases, p.17]] [[L13 SalivaryGlandDiseases.pdf#page=18|L13 SalivaryGlandDiseases, p.18]] [[L13 SalivaryGlandDiseases.pdf#page=19|L13 SalivaryGlandDiseases, p.19]] [[L13 SalivaryGlandDiseases.pdf#page=20|L13 SalivaryGlandDiseases, p.20]] [[L13 SalivaryGlandDiseases.pdf#page=21|L13 SalivaryGlandDiseases, p.21]] [[L13 SalivaryGlandDiseases.pdf#page=22|L13 SalivaryGlandDiseases, p.22]] [[L13 SalivaryGlandDiseases.pdf#page=23|L13 SalivaryGlandDiseases, p.23]] [[L13 SalivaryGlandDiseases.pdf#page=24|L13 SalivaryGlandDiseases, p.24]] [[L13 SalivaryGlandDiseases.pdf#page=25|L13 SalivaryGlandDiseases, p.25]] [[L13 SalivaryGlandDiseases.pdf#page=26|L13 SalivaryGlandDiseases, p.26]] [[L13 SalivaryGlandDiseases.pdf#page=27|L13 SalivaryGlandDiseases, p.27]] [[L13 SalivaryGlandDiseases.pdf#page=28|L13 SalivaryGlandDiseases, p.28]] [[L13 SalivaryGlandDiseases.pdf#page=29|L13 SalivaryGlandDiseases, p.29]] [[L13 SalivaryGlandDiseases.pdf#page=30|L13 SalivaryGlandDiseases, p.30]] [[L13 SalivaryGlandDiseases.pdf#page=31|L13 SalivaryGlandDiseases, p.31]] [[L13 SalivaryGlandDiseases.pdf#page=32|L13 SalivaryGlandDiseases, p.32]] [[L13 SalivaryGlandDiseases.pdf#page=33|L13 SalivaryGlandDiseases, p.33]] [[L13 SalivaryGlandDiseases.pdf#page=34|L13 SalivaryGlandDiseases, p.34]] [[L13 SalivaryGlandDiseases.pdf#page=35|L13 SalivaryGlandDiseases, p.35]] [[L13 SalivaryGlandDiseases.pdf#page=36|L13 SalivaryGlandDiseases, p.36]] [[L13 SalivaryGlandDiseases.pdf#page=37|L13 SalivaryGlandDiseases, p.37]] [[L13 SalivaryGlandDiseases.pdf#page=38|L13 SalivaryGlandDiseases, p.38]] [[L13 SalivaryGlandDiseases.pdf#page=39|L13 SalivaryGlandDiseases, p.39]] [[L13 SalivaryGlandDiseases.pdf#page=40|L13 SalivaryGlandDiseases, p.40]] [[L13 SalivaryGlandDiseases.pdf#page=41|L13 SalivaryGlandDiseases, p.41]] [[L13 SalivaryGlandDiseases.pdf#page=42|L13 SalivaryGlandDiseases, p.42]] [[L13 SalivaryGlandDiseases.pdf#page=43|L13 SalivaryGlandDiseases, p.43]]