Acute esophagitis is manifested here by increased neutrophils in the submucosa as well as neutrophils infiltrating into the squamous mucosa at the right.

                      

             

This is the view of the lower esophagus seen on endoscopy. Note the areas of dark red friable mucosa representing Barrett esophagus. Note the polypoid mass which on biopsy proved to be a moderately differentiated adenocarcinoma. This patient had a 30 year history of poorly controlled gastroesophageal reflux disease.

                      

             

Another cause for inflammation is a so-called "Barrett's esophagus" in which there is gastric-type mucosa above the gastroesophageal junction. Note the columnar epithelium to the left and the squamous epithelium at the right. This is "typical" Barrett's mucosa, because there is intestinal metaplasia as well (note the goblet cells in the columnar mucosa).

                      

             

These two endoscopic views demonstrate Barrett esophagus areas of mucosal erythema of the lower esophagus, with islands of normal pale esophageal squamous mucosa. If the area of Barrett mucosa extends less than 2 cm above the normal squamocolumnar junction, then the condition is called "short segment" Barrett esophagus, as shown below.

                      

             

This is Candida esophagitis. Tan-yellow plaques are seen in the lower esophagus, along with mucosal hyperemia. The same lesions are also seen at the upper right in the stomach.

                      

             

A herpetic ulcer is seen microscopically to have a sharp margin. The ulcer base at the left shows loss of overlying squamous epithelium with only necrotic debris remaining. In the upper GI endoscopic view below, there are rounded, erythematous ulcerations of the lower esophagus. Biopsies of these lesions reveals intranuclear inclusions in squamous epithelial cells indicative of herpes simplex virus esophagitis. This patient was immune compromised from chemotherapy.

                      

             

At high power, these infiltrating nests of neoplastic cells have abundant pink cytoplasm and distinct cell borders typical for squamous cell carcinoma. Esophageal carcinomas are not usually detected early and, therefore, have a very poor prognosis.

                      

             

Here is another varix near the gastroesophageal junction that is dark red black because it has been bleeding. (The esophagus has been turned inside out.) The plexus of veins also involves some of the upper stomach, but it is generically called the esophageal plexus of veins and, hence, bleeding here is termed esophageal variceal bleeding. Endoscopic views of esophageal varices are shown below, with dilated veins bulging into the lower esophageal lumen.

                      

             

Stomach

A 1 cm acute gastric ulcer is shown here in the upper fundus. The ulcer is shallow and sharply demarcated, with surrounding hyperemia. It is probably benign. However, all gastric ulcers should be biopsied to rule out a malignancy. The endoscopic appearance of a similar acute peptic ulcer in the prepyloric region is seen below.

                      

             

Seen above are gastric ulcers of small, medium, and large size on upper endoscopy. All gastric ulcers are biopsied, since gross inspection alone cannot determine whether a malignancy is present. Smaller, more sharply demarcated ulcers are more likely to be benign.

At high power, gastric mucosa demonstrates infiltration by neutrophils. This is acute gastritis.

                      

             

At higher magnification, the neoplastic glands of gastric adenocarcinoma demonstrate mitoses, increased nuclear/cytoplasmic ratios, and hyperchromatism. There is a desmoplastic stromal reaction to the infiltrating glands.

                      

             

This is a signet ring cell pattern of adenocarcinoma in which the cells are filled with mucin vacuoles that push the nucleus to one side, as shown at the arrow.

                      

             

Gastritis is often accompanied by infection with Helicobacter pylori. This small curved to spiral rod-shaped bacterium is found in the surface epithelial mucus of most patients with active gastritis. The rods are seen here with a methylene blue stain.

                      

             

The dark red infarcted small intestine contrasts with the light pink viable bowel. The forceps extend through an internal hernia in which a loop of bowel and mesentery has been caught. This is one complication of adhesions from previous surgery. The trapped bowel has lost its blood supply.

                      

             

This appendix was removed surgically. The patient presented with abdominal pain that initially was generalized, but then localized to the right lower quadrant, and physical examination disclosed 4+ rebound tenderness in the right lower quadrant. The WBC count was elevated at 11,500. Seen here is acute appendicitis with yellow to tan exudate and hyperemia, including the periappendiceal fat superiorly, rather than a smooth, glistening pale tan serosal surface.

                      

             

Microscopically, acute appendicitis is marked by mucosal inflammation and necrosis.

                      

             

Transmural myocardial infarction

Thin fibrous wall

Thin band of collagen

Reduced stroke volume

Aneurysm

Thrombosis

Here is a large remote cerebral infarction. Resolution of the infarction has left a huge cystic space encompassing much

of the cerebral hemisphere in this neonate.

Normal to Abnormal

Causes or risk factors ?

Pathogenesis ?

Components ?

Macroscopic & microscopic appearance ?

Clinical significance / complications ?

Prevention ?

This microscopic cross section of the aorta shows a large overlying atheroma on the left. Cholesterol clefts are numerous in this atheroma. The surface on the far left shows ulceration and hemorrhage. Despite this ulceration, atheromatous emboli are rare (or at least, complications of them are rare).

This is a high magnification of the aortic atheroma with foam cells and cholesterol clefts.

                      

             

The coronary artery shown here has narrowing of the lumen due to build up of atherosclerotic plaque. Severe narrowing can lead to angina, ischemia, and infarction.

                      

             

         

Here is an example of an atherosclerotic aneurysm of the aorta in which a large "bulge" appears just above the aortic bifurcation.Such aneurysms are prone to rupture when they reach about 6 to 7 cm in size. They may be felt on physical examination as a pulsatile mass in the abdomen.Most such aneurysms are conveniently located below the renal arteries so that surgical resection can be performed with placement of a dacron graft.

                      

             

Identification ?

Causes (etiology)?

Classification ?

Pathogenesis ?

Morphology (micro and macroscopic)?

Clinical significance ?

Temporal arteritis is one manifestation of giant cell arteritis, which can affect mainly branches of external carotid artery, but sometimes also the great vessels at the aortic arch and coronaries. There is focal granulomatous inflammation of the media.

                      

             

         

                      

             

Objective 1. ?

2. Types ?

3. Classification ?

4. Pathogenesis ?

5. Morphology ?

6. Clinical significance?

Aneurysms It is a localized abnormal dilatation of a blood vessel or heart

Hemangioma of lip

Hemangioma

Beneath the skin surface at the left are many dilated vascular channels with many red blood cells. This is a hemangioma.

Cavernous hemangioma of mouth mucosa

This is chronic osteomyelitis. Note the fibrosis of the marrow space accompanied by chronic inflammatory cells. There can be bone destruction with remodelling. Osteomyelitis is very difficult to treat.

                      

             

This is irregular new bone, or woven bone, which is forming in the region of a fracture. Osteoblasts are seen lining the irregular trabeculae, and there is an osteoclast near the center.

                      

             

         

Here is another example of a chondrosarcoma arising in the pelvis. Note the extensive nodules of white to bluish-white cartilagenous tumor tissue eroding and extending outward from the bone at the lower right. Chondrosarcomas can occur over a wide age range, and there is a slight male predominance. Many of them are slow growing, with symptoms present for a decade or more.

                      

             

This high power microscopic appearance of a chondrosarcoma demonstrates pleomorphic chondrocytes that are piled together in a haphazard arrangement. In general, chondrosarcomas occur over a wider age range than osteosarcomas, including older adults.

                      

             

         

Here is a microscopic view of metastases to bone. Such areas appear as "hot spots" on radiographic scans. If the bone is markedly weakened by the metastasis, then a "pathologic" fracture is possible.

                      

             

This femur has a large eccentric tumor mass arising in the metaphyseal region. This is an osteosarcoma (a variant known as parosteal osteogenic sarcoma) of bone. These tumors most often occur in young persons (note that the epiphysis seen at the right is still present).

                      

             

Click on the neoplasm in the image below:

                                                                    

       

         

This osteosarcoma arising in the metaphysis at the upper tibia of a teenage boy breaks through the bone cortex and extends into soft tissue. The tumor is firm and tan-white. The glistening white articular cartilage of the femoral condyle can be seen just to the right of the tumor in the opened joint space.

                      

             

The microscopic appearance of an osteosarcoma is shown here. Sarcomas have very pleomorphic cells, often with a spindle shape. One large cell with very large nuclei is seen near the center. There are islands of reactive new bone.

                      

             

The neoplastic spindle cells of osteosarcoma are seen to be making pink osteoid here. Osteoid production by a sarcoma is diagnostic of osteosarcoma.

                      

             

This is an osteochondroma of bone. This lesion appears as a bony projection (exostosis). Most are solitary, incidental lesions that may be excised if they cause local pain. There is a rare condition of multiple osteochondromatosis marked by bone deformity and by a greater propensity for development of chondrosarcoma.

                      

             

This is an osteochondroma cut into three sections. A bluish-white cartilagenous cap overlies the bony cortex. These are probably not true neoplasms, but they are a mass lesion that extends outward from the metaphyseal region of a long bone.

                      

             

         

This is the central nidus of an osteoid osteoma composed of irregular reactive new bone. Osteoid osteomas usually occur in the axial skeleton (especially tibia and femur) in bone cortex of young males in the second decade of life. An osteoblastoma is just a big osteoid osteoma in the vertebra. These lesions are benign and cured by resection.

                      

             

This is Paget's disease of bone in which the mixed osteoclastic-osteoblastic stage is present. A line of osteoblasts is present a the center-right forming new bone, but lacunae containing multinucleate osteoclasts are at the center left and lower center destroying bone. The result is a patchwork mosaic of bone without an even lamellar structure. This stage is preceded by a mainly lytic phase and is followed by a "burnt out" sclerotic phase.

                      

             

Paget's disease is seen in elderly Caucasians of European ancestry. Under polarized light, the irregularities of the bony lamellae are apparent.

                      

             

         

The curvature of the vertebral column seen here is known as scoliosis. In this case, the curve to the left in the lower lumbar region is not pronounced, and this person will be unlikely to have complications. Larger curves can progress and cause serious deformity.

                      

             

The knobby excresences at the left side of this vertebral column are due to degenerative osteoarthritis. This is the pronounced "lipping" of the vertebral bodies.

                      

             

The bone in these vertebral bodies demonstrates marked osteoporosis with thinning and loss of bony trabeculae. The second body from the right shows a greater degree of compression than the others. Osteoporosis is accelerated bone loss with age and is particularly common amongst postmenopausal women, putting them at risk for fractures (hip, wrist, vertebrae).

                      

             

         

Here is a "compressed" fracture of the vertebral column. The middle vertebral body shown here is greatly reduced in size. Such fractures are common in persons with osteoporosis in which there is accelerated bone loss, particularly older women, and can occur with even minor trauma.

This rhromboid shaped crystal of calcium pyrophosphate, which appears bluish-white (weak positive birefringence) by polarized light with red plate. Calcium pyrophosphage crystal deposition disease (sometimes called "pseudogout") is not uncommon in persons over the age of 50, and can lead to acute, subacute, or chronic arthritis of knees, wrists, elbows, shoulders, and ankles. The articular damage is progressive, though in most persons the disease is not severe.

                      

             

Click on the tophus in the image below:

                                                                    

       

This is gout. Gouty arthritis results from deposition of sodium urate crystals in joints. The joint most often affected is the first MP joint (big toe) as seen here. Acute attacks are characterized by severe pain, swelling, and erythema of the joint.

                      

             

Chronic gout leads to deposion of urates into a chalky mass known as a "tophus". Such tophi can destroy the joint and adjacent bone as seen here radiographically in sequential radiographs of the same foot (the patient did not have two right feet). In most, but not all, cases there is hyperuricemia.

                      

             

If synovial fluid is aspirated from a patient with gout, the fluid can be examined for the presence of sodium urate crystals, which are seen here to be needle shaped. If they are observed under polarized light with a red compensator, they appear yellow (negatively birefringent) in the main ("slow") axis of the compensator and blue in the opposite perpendicular direction.

                      

             

The pale areas seen here are tophi, or aggregates of urate crystals surrounded by infiltrates of lymphocytes, macrophages, and foreign body giant cells. A tophus is the characteristic finding of gout. Tophi are most likely to be found in soft tissues, including tendons and ligaments, around joints. Less commonly tophi appear elsewhere. Tophaceous gout results from continued precipitation of sodium urate crystals during attacks of acute gout.

                      

             

Here is a rheumatoid nodule. Such nodules are seen in patients with severe rheumatoid arthritis and appear beneath the skin over bony prominences such as the elbow. They can occasionally appear in visceral organs. There is a central area of fibrinoid necrosis surrounded by pallisading epithelioid macrophages. and other mononuclear cells.

                      

             

This is the synovium in rheumatoid arthritis. There is chronic inflammation with lymphocytes and plasma cells that produce the blue areas beneath the nodular proliferations. This "pannus" is destructive and produces erosion of the articular cartilage, eventually destroying the joint.

                      

             

This rhromboid shaped crystal of calcium pyrophosphate, which appears bluish-white (weak positive birefringence) by polarized light with red plate. Calcium pyrophosphage crystal deposition disease (sometimes called "pseudogout") is not uncommon in persons over the age of 50, and can lead to acute, subacute, or chronic arthritis of knees, wrists, elbows, shoulders, and ankles. The articular damage is progressive, though in most persons the disease is not severe.

                      

             

Chronic gout leads to deposion of urates into a chalky mass known as a "tophus". Such tophi can destroy the joint and adjacent bone as seen here radiographically in sequential radiographs of the same foot (the patient did not have two right feet). In most, but not all, cases there is hyperuricemia.