Lect.2. salivary gland pathology

SALIVARY GLAND PATHOLOGY

SMS 2044Dr. Mohanad r. alwan

SALIVARY GLAND DISEASES Although diseases primary to the

major salivary glands are in general uncommon, the parotids bear the brunt of these involvements.

Among the many possible disorders, attention is restricted here to sialadenitis and salivary gland tumors.

Sialadenitis • Inflammation of the major salivary

glands may be of viral, bacterial, or autoimmune origin.

• Dominant among these causations is the infectious viral disease mumps, which may produce enlargement of all the major salivary glands but predominantly the parotids.

Micrograph showing chronic sialadenitis.

SALIVARY G……..

Although a number of viruses may cause mumps, the dominant cause is a paramyxovirus, an RNA virus related to the influenza and parainfluenza viruses.

It usually produces a diffuse, interstitial inflammation marked by edema and a mononuclear cell infiltration and, sometimes, by focal necrosis.

Although childhood mumps is self-limited and rarely leaves residua, mumps in adults may be accompanied by pancreatitis or orchitis.

Bacterial sialadenitis most often occurs secondary to ductal obstruction resulting from stone formation (sialolithiasis),

but it may also arise after retrograde entry of oral cavity bacteria under conditions of severe systemic dehydration such as the postoperative state.

The sialadenitis may be largely interstitial or cause focal areas of suppurative necrosis or even abscess formation.

Chronic sialadenitis arises from decreased production of saliva with subsequent inflammation.

The dominant cause is autoimmune sialadenitis, which is almost invariably bilateral.

This is seen in Sjögren syndrome. All of the salivary glands (major and minor), as well as the lacrimal glands, may be affected in this disorder, which induces dry mouth (xerostomia) and dry eyes (keratoconjunctivitis sicca).

The combination of salivary and lacrimal gland inflammatory enlargement, which is usually painless, and xerostomia.

The causes include sarcoidosis, leukemia, lymphoma, and idiopathic lymphoepithelial hyperplasia.

TREATMENTMedical management - Hydration,

antibiotics (oral versus parenteral), warm compresses and massage, sialogogues (increases the flow of sliva)

Surgical management - Consideration of incision and drainage versus excision of the gland in cases refractory to antibiotics, incision and drainage with abscess formation, gland excision in cases of recurrent acute sialadenitis

The salivary glands give rise to a diversity of tumors that belies their small size.

About 80% of tumors occur within the parotid glands and most of the others in the submandibular glands.

The dominant tumor arising in the parotids is the benign pleomorphic adenoma, which is sometimes called a mixed tumor of salivary gland origin.

Salivary Gland Tumors

SALIVARY GLAND BENIGN TUMORS

pleomorphic adenomas originate from the intercalated duct cells and myoepithelial cells

oncocytic tumors originate from the striated duct cells

acinous cell tumors originate from the acinar cells,

Mucoepidermoid tumors and squamous cell carcinomas develop in the excretory duct cells.

STAGING SYSTEM FOR MAJOR SALIVARY GLAND CANCER

Tx Primary tumor cannot be assessed T0 No evidence of primary tumor T1 Tumor < 2cm in greatest dimension T2 Tumor 2-4 cm in greatest dimension T3 Tumor 4-6 cm in greatest dimension T4 Tumor > 6 cm in greatest dimension

All categories are subdivided: (a) no local extension; (b) local extension.

Local extension is clinical or macroscopic invasion of skin, soft tissue, bone, or nerve.

Microscopic evidence alone is not a local extension for classification purposes.

NORMAL HISTOLOGY

PLEOMORPHIC ADENOMA

PLEOMORPHIC ADENOMA

Epithelial Components• Tubular and cord-like arrangements• Cells contain a moderate amount of cytoplasm• Mitoses are rare

Stromal or “mesenchymal” Components• Can be quite variable• Attributable to the myoepithelial cells• Most tumors show chondroid (cartilaginous)

differentiation• Osseous metaplasia not uncommon• Relatively hypocellular and composed of pale

blue to slightly eosinophilic tissue.

PLEOMORPHIC ADENOMA pleomorphic adenoma

contains both epithelial (E) and stromal (S) components. Pleomorphic adenoma. Slowly enlarging neoplasm in the parotid gland of many years duration.

The bisected, sharply circumscribed, yellow-white tumor can be seen surrounded by normal salivary gland tissue

PLEOMORPHIC ADENOMA The diverse microscopic

pattern of this lesion is one of its most characteristic features.

Islands of cuboidal cells arranged in ductlike structures is a common finding.

Loose chondromyxoid stroma, hyalinized connective tissue, cartilage(arrows) and even osseous tissue are observed.

This neoplasm is typically encapsulated, although tumor islands may be found within the fibrous capsule.

PLEOMORPHIC ADENOMA

A, Low-power view showing a well-demarcated tumor with adjacent normal salivary gland parenchyma. B, High-power view showing epithelial cells as well as myoepithelial cells found within a chondroid matrix material.

WARTHIN'S TUMOR

Warthin's tumor (benign papillary cystadenoma lymphomatosum)the second most common benign tumor of the parotid glandIt accounts for 2-10% of all parotid gland tumors Bilateral in 10% of the casesmay contain mucoid brown fluid in FNA

WARTHIN’S TUMOR

Mid Power Thought to arise

from salivary gland inclusions within lymph nodes.

WARTHIN’S TUMOR

Epithelial ComponentConsists of papillary fronds which demonstrate

2 layers of oncocytic epitheilal cellsCytoplasm stains deep pink and shows

granularity of an abundance of mitochondriaOccasionally undergoes squamous metaplasia

(may mistakenly diagnose SCCa on FNA)

WARTHIN’S TUMOR

Lymphoid ComponentAn abundance of this is presentOccasional germinal centres will be seenLymphoid tissue forms the core or papillary

structuresBoth lymphoid and oncocytic epithelial elements must be present to diagnose Warthin’s

WARTHIN’S TUMOR

oHigh Power oLymphocytc

infilterates.oBilayer of

epithilium.

WARTHIN’S TUMOR

A, Low-power view showing epithelial and lymphoid elements. Note the follicular germinal center beneath the epithelium. B, Cystic spaces separate lobules of neoplastic epithelium consisting of a double layer of eosinophilic epithelial cells based on a reactive lymphoid stroma.

MONOMORPHIC ADENOMA

Similar to Pleomorphic Adenoma except no mesenchymal stromal component• Predominantly an epithelial component

More common in minor salivary glands (upper lip)

12% bilateralRare malignant potentialTypes:

• Basal Cell Adenoma• Canicular Adenoma• Myoepithelioma Adenoma• Clear Cell Adenoma• Membranous Adenoma• Glycogen-Rich Adenoma

BASAL CELL ADENOMA

A monomorphic adenoma It is composed of uniform

basaloid epithelial cells with a monomorphous pattern.

The arrangement of tumor cells may be trabecular, tubular or solid.

Histologically, these tumors are distinguished from pleomorphic adenomas by their absence of chondromyxoid stroma and the presence of a uniform epithelial pattern.

MALIGNANT SALIVARY GLAND TUMORS

MUCOEPIDERMOID CARCINOMA

Mucoepidermoid carcinoma (MEC) is the most common malignant tumor of the parotid gland and the second-most common malignancy (adenoid cystic carcinoma is more common) of the submandibular and minor salivary glands.

Stained + by musicarmine.MECs constitute approximately 35% of

salivary gland malignancy, and 80% to 90% of MECs occur in the parotid gland.

MUCOEPIDERMOID CARCINOMA • MECs contain two major

elements:• Mucin-producing cells

and• Epithelial cells of the

epidermoid variety. • MEC is divided into low-

grade (well differentiated).

• High-grade (poorly differentiated).

They contain three cellular elements in varying proportions: squamous cells, mucus-secreting cells, and "intermediate" cells.

Mucous cells (mucocytes) can occur singly or in clusters, and they have pale and sometimes foamy cytoplasm, a distinct cell boundary, and small, peripherally placed, compressed nuclei.

Mucocytes often form the lining of cysts or duct-like structures.

Occasionally mucocytes are so scanty that they can be identified with confidence only by using stains such as mucicarmine.

Epidermoid cells may be uncommon and focally distributed.

They have abundant eosinophilic cytoplasm, but they rarely show keratin pearl formation or dyskeratosis.

Oncocytic metaplasia is seen occasionally.

MUCOEPIDERMOID CARCINOMA

A, Mucoepidermoid carcinoma showing islands having squamous cells as well as clear cells containing mucin. B, Mucicarmine stains the mucin reddish-pink. (Courtesy of Dr. James Gulizia, Brigham and Women's Hospital, Boston.)

ADENOID CYSTIC CARCINOMA

Adenoid cystic carcinoma with Swiss cheese pattern.

It is the second-most common malignant tumor of the salivary glands.

ACC is the most common malignant tumor found in the submandibular, sublingual, and minor salivary glands.

ADENOID CYSTIC CARCINOMA

Nerve (N) invaded by adenoid cystic carcinoma (the blue area surrounding the nerve).

Spread may occur by emboli along the nerve lymphatics

ADENOID CYSTIC CARCINOMA

Adenoid cystic carcinoma in a salivary gland. A, Low-power view. The tumor cells have created a cribriform pattern enclosing secretions. B, Perineural invasion by tumor cells.

ACINIC CELL CARCINOMA

The acinic cell adenocarcinoma occurs mainly in the parotid gland, also known as blue dot tumor.

Classic multicystic pattern.

Stained by PAS.Cells heavily stained.

ACINIC CELL CARCINOMA

This lesion is characterized by a benign histomorphologic picture but by occasional malignant behavior.

Bilateral involvement occurs in 3% of patients, making acinic cell carcinoma the second-most common neoplasm, after Warthin’s tumor, to exhibit bilateral presentation.

HODGKIN'S LYMPHOMA

Hodgkin's disease involving the parotid gland. 

Note the Reed-Sternberg cell.  (Fine needle aspiration, Pap, 630x)

SALIVARY GLAND TUMORS

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HABIS

QUESTION??????????????

Q1. Mention the common types of salivary gland benign tumors with origin of each.

Q2. Identify the histological feature for mucoepidermoid carcinoma