Cui Dongmei. Atlas of Histology: with functional and clinical correlations. 1st ed

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Figure 16-12A Liver Acinus

Figure 16-12B Portal Triad, Liver

Figure 16-12C Clinical Correlation: Alcoholic Fatty Liver (Steatosis)

Figure 16-13A Hepatocytes and Hepatic Sinusoids, Liver

Figure 16-13B Space of Disse, Hepatocyte

Figure 16-14A A Representation of Bile Canaliculi and Hepatocytes

Figure 16-14B Bile Canaliculus, Hepatocytes

Gallbladder

Figure 16-15A Gallbladder

Figure 16-15B Epithelial Cells Lining the Gallbladder

Figure 16-16A Clinical Correlation: Hepatitis C

Figure 16-16B Clinical Correlation: Gallstones

Synopsis 16-2 Pathological and Clinical Terms for the Digestive Glands and Associated Organs

Introduction and Key Concepts

for the Digestive Glands and Associated

Organs

Digestive glands and associated organs include the major

salivary glands, pancreas, liver, and gallbladder. These organs

are located outside the wall of the digestive tract. Their secretory

products are delivered into the digestive tract via a duct system.

Major Salivary Glands

The major salivary glands produce saliva and empty into the

oral cavity. Saliva is 99% water and contains protein, enzymes,

glucose, cholesterol, urea, uric acid, ions (e.g., Na

, K

, Ca

HCO

), and antibacterial agents (lactoferrin, lysozyme, and

IgA). Saliva is produced by both serous and mucous cells in

the salivary glands. It plays important roles in aiding digestion,

lubrication, protection, buffering, wound healing, maintaining

the integrity of the esophagogastric epithelium, perception of

taste, and in hardening of the enamel of the teeth. There are

three major salivary glands: the parotid, submandibular, and

sublingual glands. These are paired glands and have similar

structures of secretory units (acini) and duct systems, including

intralobular ducts (intercalated and striated ducts), interlobular

ducts, lobar ducts, and a main duct (Figs. 16-1 and 16-8B).

1. The parotid gland is the largest of the three major salivary

glands. This gland is surrounded by a connective tissue

capsule. Its secretory unit is composed of only serous cells,

which produce watery proteinaceous ﬂ uid (Figs. 16-3B and

16-4A).

2. The submandibular gland is the second largest salivary

gland. This gland is surrounded by a connective tissue cap-

sule. It is a mixed gland, although the majority of cells are

serous cells. The secretory unit is composed of both serous

and mucous cells. Serous demilunes (serous cell caps on the

mucous cells) are present in the submandibular gland (Figs.

16-5A to 16-7B).

3. The sublingual gland is the smallest salivary gland. This

gland is not surrounded by a connective tissue capsule. This

is also a mixed gland, but is predominately mucous. Acini

that are completely serous are few, but serous demilunes are

commonly present. Striated ducts are not as obvious as in

the other two types of salivary glands (Fig. 16-8A,B).

Pancreas

The pancreas has endocrine and exocrine portions. The

endocrine portion (islets of Langerhans) secretes blood glucose–

regulating hormones (insulin, glucagon, somatostatin, and pan-

creatic polypeptide), which are released into the bloodstream

(see Chapter 17, “Endocrine System”). The exocrine portion

produces pancreatic secretions (juice), which are carried by

pancreatic ducts. Most of these secretions go to the main pan-

creatic duct, which joins the hepatopancreatic ampulla (ampulla

of Vater) and then enters the duodenum through the major duo-

denal papilla (papilla of Vater). The ampulla is surrounded by

smooth muscle called the sphincter of the ampulla (sphincter

of Oddi [Fig. 16-9A]). A small portion of the pancreatic secre-

tion is carried by the accessory pancreatic duct and enters the

duodenum through the minor duodenal papilla. The pancreatic

duct system includes intralobular ducts, interlobular ducts, and

a main duct. The pancreas does not have striated ducts, and

the smallest intralobular ducts are intercalated ducts. The initial

portions of the intercalated ducts are lined by centroacinar cells.

The initial pancreatic secretions (enzymes) are produced by pan-

creatic acinar cells, and a large volume of ﬂ uid (water, sodium,

and bicarbonate) is added by intercalated duct cells. Pancreatic

secretions contain enzymes for digesting proteins, carbohy-

drates, and fats. The major components include water, sodium,

bicarbonate ions, trypsinogen, chymotrypsinogen, procarboxy-

polypeptidase, amylase, lipase, cholesterol esterase, phospho-

lipase, and nucleases. The main enzymes for digesting protein

are trypsinogen, chymotrypsinogen, and procarboxypolypepti-

dase; the main enzyme for digesting carbohydrates is amylase;

and the main enzymes for digesting fat are lipase, cholesterol

esterase, and phospholipase. The nucleases degrade nucleic

acids. When the pancreatic digestive enzymes are ﬁ rst synthe-

sized by the pancreatic cells, they are in an inactive stage. They

become activated after they enter the duodenum and come into

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Organ Systems

contact with enterokinase in the glycocalyx. The glycocalyx is

an extracellular polymeric material (glycoprotein), which coats

the surface of microvilli in the small intestines (Figs. 16-9A to

16-10B).

Liver

The liver also plays both endocrine and exocrine roles. Its

endocrine role is in synthesizing and releasing plasma proteins,

such as ﬁ brinogen, prothrombin, lipoproteins, and albumins,

into the bloodstream. Its exocrine role is the production of bile.

Bile is important in emulsifying and degrading fat into smaller

molecules and in carrying wastes out of the body. Bile contains

water, bile salts, bilirubin, cholesterol, fatty acids, lecithin, and

electrolytes. Bile is produced by hepatocytes and is collected

by bile canaliculi; it drains into the hepatic duct, then into the

cystic duct, and ﬁ nally enters the gallbladder (Figs. 16-11 and

16-15A). Other functions of the liver include detoxiﬁ cation;

involvement in lipid, carbohydrate, and protein metabolism;

and storage of iron, blood, glycogen, triglycerides (lipid drop-

lets), and vitamins A, D, and B12. The liver is supplied by the

portal veins and the hepatic arteries at the portal triads. The

hepatic arteries carry oxygen-rich blood, and the portal veins

carry nutrient-rich blood to the hepatic sinusoids through their

branches (hepatic arterioles and portal venules). The hepatocytes

are not in direct contact with the blood stream. A small space

between the hepatocyte and the endothelium of the sinusoids

is called the perisinusoidal space or space of Disse. The discon-

tinuous endothelium of the sinusoids allows proteins, nutrients,

wastes, and plasma components (but not blood cells) from the

hepatic sinusoids to enter the space of Disse. Hepatocytes take

up nutrients and transport wastes, such as bilirubin, into the

bile. The central veins collect the exchanged blood from sinu-

soids and drain into the sublobular veins and then into the large

hepatic veins. The basic structure of the liver includes the classic

lobule, the

portal lobule, and the liver acinus (Figs. 16-11 to

16-12A).

Gallbladder

The gallbladder is a pear-shaped, saclike organ closely associ-

ated with the liver. It stores, concentrates, and releases bile.

When the smooth muscle (muscularis) of the gallbladder

contracts, bile is released from the gallbladder through the

cystic duct into the bile duct. This joins the hepatopancreatic

ampulla and drains into the duodenum at the major duode-

nal papilla. The wall of the gallbladder is composed of three

layers: (1) mucosa, which includes epithelium (simple colum-

nar epithelium) and lamina propria; (2) muscularis, which

contains interlacing smooth muscle bundles and contracts in

response to cholecystokinin, which is released by enteroen-

docrine cells in the small intestine (the smooth muscle of the

gallbladder extends from the body into the neck where it is

known as the spiral valve of Heister and is vital in controlling

gallbladder ﬂ ow); and (3) serosa/adventitia, a connective layer

with a lining of mesothelium (serosa) or without mesothelium

(adventitia). Most of the outer surface of the gallbladder is

covered with serosa, which is continuous with the peritoneum

that covers the liver. A small region of the gallbladder is cov-

ered by adventitia, which attaches the gallbladder to the liver

(Fig. 16-15A,B).

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Figure 16-1. Overview of the digestive glands and associated organs.

The major digestive glands include the salivary glands, pancreas, and liver. Although the gallbladder is not a gland, it is closely associated

with the liver and digestive system. The digestive glands and gallbladder are located outside of the digestive tract. Their ducts carry

their products (saliva) into the oral cavity or into the lumen of the duodenum of the small intestine (pancreatic secretions and bile). The

salivary glands include the major salivary glands and the minor salivary glands. The parotid, submandibular, and sublingual glands are

the three major salivary glands. These glands are either serous glands or mixed glands (both serous and mucous). Most of the minor

salivary glands are mucous or mixed glands, with only von Ebner glands being entirely serous glands (see Fig. 14-6A). For details of clas-

siﬁ cation of the glands see Chapter 3, “Epithelium and Glands.” The pancreas includes an endocrine portion (islets of Langerhans) and

an exocrine portion. The endocrine portion secretes hormones into the bloodstream (see Chapter 17, “Endocrine System”), whereas the

exocrine portion has ducts that carry enzyme products into the lumen of the duodenum (see Figs. 16-9A to 16-10B). The liver produces

bile, which is carried by the bile duct system into the gallbladder (see Figs. 16-11 and 16-15A). The liver also aids in the metabolism of

lipids, carbohydrates, and proteins; stores iron, glycogen, triglycerides, and vitamins A, D, and B12; and detoxiﬁ es certain toxic sub-

stances in the blood. The gallbladder stores, concentrates, and releases bile into the duodenum (see Fig. 16-15A,B).

Parotid

gland

Liver

Gallbladder

Pancreas

Main duct of

parotid gland

Submandibular

gland

Sublingual

gland

Main duct of

submandibular

gland

Digestive Glands and Associated Organs

I. Major Salivary Glands

A. Parotid glands (serous)

B. Submandibular glands (mixed, predominately serous)

C. Sublingual glands (mixed, predominately mucous)

II. Pancreas

A. Exocrine portion

B. Endocrine (islets of Langerhans) portion

III. Liver

A. Central artery

B. Portal triad

C. Liver lobules

1. Classic lobule

2. Portal lobule

3. Hepatic acinus

IV. Gallbladder

A. Mucosa

B. Muscularis

C. Serosa

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Digestive Glands and Associated Organs with Figure Numbers

Parotid Glands

Figure 16-3B

Figure 16-4A

Figure 16-4B

Figure 16-4C

Submandibular Glands

Figure 16-5A

Figure 16-5B

Figure 16-6A

Figure 16-6B

Figure 16-7A

Figure 16-7B

Sublingual Glands

Figure 16-8A

Figure 16-8B

Figure 16-8C

Pancreas

Figure 16-9A

Figure 16-9B

Figure 16-9C

Figure 16-10A

Figure 16-10B

Liver

Figure 16-11

Figure 16-12A

Figure 16-12B

Figure 16-12C

Figure 16-13A

Figure 16-13B

Figure 16-14A

Figure 16-14B

Figure 16-16A

Gallbladder

Figure 16-15A

Figure 16-15B

Figure 16-16B

Figure 16-2. Orientation of detailed digestive glands and associated organs illustrations.

Fig. 16-8A,B

Fig. 16- 5A,B

Fig. 16- 6A,B

Fig. 16- 7A,B

Fig. 16-3B

Fig. 16-4A

Fig. 16-9B

Fig. 16-10A,B

Fig. 16-15A,B

Fig. 16-12A,B

Fig. 16-13A,B

Fig. 16-14A,B

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Salivary Glands

Figure 16-3A. General structure of the major salivary glands.

The parotid, submandibular, and sublingual glands are structurally very similar to one another, although they produce various

secretions. Each unit of the salivary glands can be divided into a secretory portion and a duct system. The secretory portion contains

serous cells, mucous cells, or a mixture of both. These secretory cells are arranged into acini resembling grapes on a stem (interca-

lated duct). Several serous cells form a cap, called a serous demilune, on the outer aspect of mucous cells; this arrangement can be

found in the mixed glands. A capsule (dense connective tissue layer) surrounds an entire gland. Connective tissue septa penetrate the

gland and subdivide it into lobes and lobules. The duct system includes intralobular ducts (located within the lobules), interlobular

ducts (outside or between the lobules), lobar ducts, and a main duct. The intralobular ducts include intercalated ducts and striated

ducts. The main duct empties the secretory products (saliva) into the oral cavity.

Figure 16-3B. Parotid gland. H&E, 130 skin, palm.

The parotid glands are paired glands and are the largest of the major

salivary glands. They are located anterior to and below the lower

half of the ear, and superior, posterior, and deep to the ramus of

the mandible. The main duct of each parotid gland passes through

the cheek and opens into the oral cavity near the second upper

molar tooth (see Fig. 16-1). The parotid glands are composed of

serous acini and ducts. They are classiﬁ ed as compound (branched)

acinar glands based on their duct shape and secretory units (see Fig.

3-27A). This photomicrograph shows striated ducts (intralobular

ducts) located in the lobules. The striated ducts are lined by taller

cuboidal (or columnar) cells with centrally located nuclei (see Fig.

16-7A). Connective tissue septa divide the gland into small lobules,

and there are some adipose cells distributed in among the serous

acini. Each acinus is formed by several serous cells with basally

positioned dark nuclei (Fig. 16-4A).

Salivary Gland Duct System

D. Cui

Lobar duct

(a few branches)

Interlobular duct

(multiple branches)

Intralobular duct

(multiple branches)

Secretory portion

Duct system

Serous

cells

Serous

acinus

Serous

demilune

Intercalated

ducts

Lumen of the

Intercalated ducts

Striated

ducts

Mucous

cells

Striated

ducts

Striated

ducts

Striated

duct

Striated

duct

Septa

Adipose

cells

Adipose

cells

Serous acini

D. Cui

(Serous, mucous, or mixed cells)

(Simple low cuboidal epithelium)

Small intralobular duct

(Intercalated duct)

Interlobular duct

Main duct

(Stratified columnar epithelium)

(striated duct)

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Figure 16-4A. Parotid glands. H&E, 295; inset 97

Parotid glands contain only serous secretory cells. There

are some adipose cells scattered throughout the gland. All

three types of salivary glands have similar duct systems. The

intercalated ducts are shown here; they have a small lumen

and are lined by lower cuboidal cells with basally located

nuclei. The inset shows a large interlobular duct that is

lined by stratiﬁ ed columnar cells and is surrounded by a

large amount of connective tissue. The diameter of the ducts

gradually increases from the intercalated ducts to the large

interlobular ducts, and their lining cells increase in height

and in number of layers (see Fig. 16-3A). The main duct

(duct of Stenson) of the parotid gland traverses the buccina-

tor muscles and opens opposite the secondary upper molars

(see Fig. 16-1). All three types of salivary glands receive para-

sympathetic innervation. The parotid gland is innervated by

the glossopharyngeal nerve (cranial nerve [CN] IX).

Adipose

cells

Adipose

cells

Interlobular

duct

Interlobular

duct

Intercalated

duct

Intercalated

duct

Serous

cells

Serous

cells

Intercalated

duct

Intercalated

duct

CLINICAL CORRELATIONS

Figure 16-4B.

Pleomorphic Adenoma. H&E, 55

Pleomorphic adenoma, also called benign mixed tumor,

is the most common benign salivary gland tumor

. The

majority, approximately 80%, occur in the parotid gland,

most of which are in the superﬁ cial lobe, and are benign

pleomorphic adenomas. The tumor may also involve

submandibular, sublingual, and minor salivary glands. It

is characterized by a slow-growing, mobile, and painless

parotid mass. Most patients are not aware of the tumor

for years. The mass itself is typically well demarcated, but

may be nodular in appearance. Histologically, the neo-

plasm is composed of epithelial and myoepithelial cells in

a chondromyxoid background. Fine needle biopsy is use-

ful in the diagnosis of pleomorphic adenoma. After sur-

gery, pleomorphic adenomas may recur. Rapid growth

of a mass in the same area after surgery may signify

malignant transformation of the residual adenoma called

carcinoma expleomorphic adenoma. This photomicro-

graph shows nests of myoepithelial cells in a myxoid

background.

Figure 16-4C.

Parotid Cyst. H&E, 11

A parotid cyst is a ﬂ uid-ﬁ

lled closed cavity occurring

within the parenchyma of the parotid gland and is usu-

ally caused by trauma, infections, salivary gland stones,

or tumors. Physical exam usually reveals a painless

lump or swelling. As the cyst enlarges, it may interfere

with chewing, swallowing, and speaking. Additionally,

parotid cysts may become infected. Histologically, the

cyst is lined by an epithelium, and the cavity is ﬁ lled

with ﬂ uid or mucus. The surrounding stroma shows

dense ﬁ brosis and may be inﬁ ltrated by aggregates of

lymphocytes, as shown in this slide. If necessary, surgical

removal of the cyst is recommended.

Myoepithelial

cells

Myxoid

background

Parotid

gland

Cyst

Stroma

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Septum

Serous

demilunes

Serous

demilunes

Septum

Serous

acini

Serous

acini

Serous

demilune

demilun

Serous

demilune

Striated

duct

Striated

duct

Mucous

cells

Mucous

cells

Figure 16-5A. Submandibular glands. H&E, 136; inset 408

Submandibular glands are also paired glands. They are smaller than

the parotid glands, but larger than the sublingual glands. Each sub-

mandibular gland is divided into superﬁ cial (large) and deep (small)

lobes and is located under the ﬂ oor of the oral cavity adjacent to

the mandible (see Fig. 16-1). The main duct of the submandibular

gland drains saliva into the oral cavity at the sublingual caruncles on

both sides of the frenulum linguae. The submandibular glands are

mixed glands that contain predominantly serous cells but also some

mucous cells. They are classiﬁ ed as compound (branched) tubulo-

acinar glands (see Fig. 16-3A; see also Chapter 3, “Epithelium and

Glands,” Fig. 3-28A). Serous cells are arranged into many acini, and

mucous cells are arranged as acini or tubular structures, which may

have caps of serous cells (serous demilunes). Submandibular glands

are innervated by parasympathetic nerve ﬁ bers from branches of

the facial nerve (CN VII).

Myoepithelial

cell

Serous acinar

cell

Secretory

granules

Nucleus of the

acinar cell

Nucleus of the

acinar cell

Lumen

RER

Figure 16-5B. Serous acinus, submandibular gland. EM, 3,937; inset (color), H&E, 1,079

Several serous acinar cells arranged in an acinus and sharing a common lumen are shown. The serous lumens are smaller than those

of a mucous acinus (see Fig. 16-6A). Each secretory cell has a relatively large nucleus and numerous rough endoplasmic reticulum

(RER) cisterns in the basal portion of the cytoplasm. These features indicate their active protein synthesis. Secretory granules are

usually located on the apical region of the cells (color inset). Secretory granules are not seen in this electron micrograph because they

have already been discharged from these particular cells. The inset shows an acinus with secretory cells having round nuclei located

basally and many secretory granules in the apical portions of the secretory cells. A myoepithelial cell with a ﬂ at nucleus is present

here, located beneath the serous cell. It is a contractile cell and contains smooth muscle myosin. The myoepithelial cells contract and

move the secretory products toward the intercalated duct.

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Figure 16-6A. Mucous acinus, submandibular gland. EM, 6,818; inset (color) H&E, 598

This is an example of a mucous acinus, showing numerous large secretory granules in the apical region of the cells. These granules

contain mucins, which are synthesized within the cells. The nuclei of the mucous cells are ﬂ attened and lie against the basement

membrane. Mucous cells have less RER than serous cells. Myoepithelial cells share the basement membrane with mucous cells.

Myoepithelial cells have long cellular processes that can contract, promoting mucous cells to discharge their secretory products into

the lumen of the intercalated ducts.

Nucleolus

Secretory

granules

Secretory

granules

Nucleus of mucous

acinar cell

Nucleus of mucous

acinar cell

Process of

myoepithelial cell

Process of

myoepithelial cell

Lumen

Nucleus of the

myoepithelial cell

Nucleus of the

myoepithelial cell

Mucous

acinar cell

Lumen

Nucleus of

mucous

acinar cell

Nucleolus

CLINICAL CORRELATION

Squamous cell

carcinoma

Submandibula

gland

Figure 16-6B.

Squamous Cell Carcinoma of the Tongue.

H&E, 83

Squamous cell carcinoma of the tongue is a malignant oral

neoplasm representing the most common intraoral cancer.

Squamous cell carcinoma is usually asymptomatic in the early

stages, but local pain, difﬁ culty swallowing, and dysphagia

are common in the late stages. Clinically, the neoplasm may

appear as a red or white nonhealing ulcer or exophytic mass,

most commonly found on the lateral aspect of the tongue.

This image shows a squamous cell carcinoma on the ﬂ oor

of the mouth invading the submandibular glands. The major

risk factors for oral and tongue squamous cell carcinoma

include smoking and alcohol consumption, chronic irrita-

tion, and chewing tobacco. Pathologically, the cancer cells

show large, irregular and darkly stained nuclei. This cancer

tends to metastasize though the lymphatic system. Surgical

removal of the primary growth and related lymphatic nodes,

chemotherapy, and radiation therapy are treatment options.

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Figure 16-7A. Striated duct, submandibular gland. H&E, 845

Striated ducts are lined by simple cuboidal or columnar cells with centrally positioned nuclei. Their cytoplasm shows striations in

the basolateral region, hence the name. The striations are due to deep indentations in the plasma membrane (basolateral folds),

which increase the surface area occupied by pumps involved in ion and ﬂ uid transport. The folds contain many mitochondria that

provide adenosine triphosphate for active transport. The striated ducts collect primary saliva (produced by acinar cells) from the

intercalated ducts. The main function of the striated ducts is modulation of the pH and ion composition of the saliva. The striated

ducts remove Na

and Cl

−

ions in the primary saliva from the lumen and transport these ions to the interstitial tissues. Striated ducts

also pump K

and HCO

−

into the saliva ﬂ uid. This results in a hypotonic alkaline saliva (secondary saliva), which moves from the

striated ducts to the interlobular ducts, then to the main duct, and eventually enters the oral cavity. Saliva plays important roles in

moistening and cleansing the oral cavity, helping to repair oral tissues, inﬂ uencing the pH (buffering) in the oral cavity, stimulating

the taste buds, helping to digest food, helping in the mineralization and hardening of the enamel of posterupted teeth, and destroying

bacteria by antimicrobial action.

D. Cui

Striations

Interstitial

tissue

Interstitial

tissue

Serous

acinus

Serous

acinus

Lumen

HCO

Interstitial

tissue

Striated

duct

Basal

membrane

enfolding

Mitochondrion

Nucleus

Basement

membrane

Lumen

Figure 16-7B. Intralobular duct, sub-

mandibular gland. EM, 3,382; inset

6,779

The duct shown here appears to be at the

transition between a striated intralobular

duct and an interlobular duct. Some of

the lining cells, such as the one shown in

the inset, have features of a striated duct

in that there are extensive basolateral

folds containing numerous mitochondria.

These are the same features that account

for the eosinophilic striations seen in these

cells in H&E-stained sections for light

microscopy.

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Figure 16-8A. Sublingual glands. H&E, 123

Sublingual glands are the smallest of the three major salivary

glands. They are paired glands and are located deep in the ﬂ oor

of the oral cavity, anterior to the submandibular glands. They

are covered by the oral mucosa, but have no capsule (dense con-

nective tissue) enclosing them as the other two major salivary

glands do. Sublingual glands have about 8 to 20 small ducts,

which open into the crest of the sublingual fold on the ﬂ oor

of the oral cavity. They are mixed glands, and contain serous

and mucous secretory cells, but predominantly mucous cells. As

in submandibular glands, serous demilunes are present; sublin-

gual glands are also classiﬁ ed as compound (branched) tubu-

loacinar glands (see Figs. 16-3A and 3-28A). Two intralobular

ducts located inside connective tissue septa are labeled here.

Sublingual glands are innervated by parasympathetic nerve

ﬁ bers from branches of the facial nerve (CN VII).

Mucous

acini

Mucous

acini

Interlobular

ducts

Interlobular

ducts

Septum

Mucous cell

Serous demilune

Capillary

Mucous acini

Intralobular

duct

Intralobular

duct

Serous demilune

Figure 16-8B. Sublingual gland. H&E, 179; inset 408

Mucous cells make up the majority of the cells in the sublingual

glands and are distributed throughout the gland. Some mucous

cells may be capped with serous cells (serous demilunes); very

occasionally complete serous acini may be present. Mucous cells

stain lighter than serous cells and they are often arranged in an

elongated tubular structure (mucous acinus) with a ﬂ attened or

round lumen. These mucous cells have dark nuclei located at the

basal end of the cells. Nuclei of the mucous cells are smaller and

ﬂ atter than in serous cells. The large intralobular ducts in the

sublingual glands are short, and the striations of the ducts are

not particularly obvious. The small intralobular ducts (interca-

lated ducts) are similar to those of the other two major salivary

glands; they receive secretions directly from secretory cells.

CLINICAL CORRELATION

Lymphocyte

Sublingual

gland tissue

Figure 16-8C.

Sialadenitis. H&E, 109

Sialadenitis is the inﬂ

ammation of salivary tissues or salivary

glands caused by injuries, viral or bacterial infection, auto-

immune disease, or stones within the salivary gland ducts.

Ductal obstruction due to stones (sialolithiasis) may lead to

painful gland enlargement and abscess, most often because of

bacteria such as Staphylococcus aureus. Histologic ﬁ ndings in

acute sialadenitis would show inﬁ ltration of glandular paren-

chyma by abundant neutrophils. The most common cause of

viral sialadenitis is mumps, often affecting the parotid glands.

Sjögren syndrome is an autoimmune disease characterized by

periductal and periacinar lymphocytic inﬁ ltrates, formation of

lymphatic nodules, periductal ﬁ brosis, and destruction of the

glands. This image shows chronic sialadenitis with a lympho-

cytic inﬁ ltrate within the glandular parenchyma.

CUI_Chap16.indd 314 6/2/2010 6:42:37 PM