Bone, Joints, and Soft Tissue Tumors – Chapter 26 Peripheral Nerve and Skeletal Muscle – Chapter 27

Question 1

Skeletal muscle is derived from what embryonic germ layer?

Answer 1

Mesoderm

Question 2

What is the functional contractile unit of skeletal muscle? Which contractile proteins create the thick and thin filaments?

Answer 2

Myofibril
Thick filament – myosin
Thin filament – actin

Question 2

What is the functional contractile unit of skeletal muscle? Which contractile proteins create the thick and thin filaments?

Answer 2

Myofibril
Thick filament – myosin
Thin filament – actin

Question 3

Bone matrix is the extracellular component of bone. It is composed of an organic component known as osteoid and a mineral component. Osteoid is made up predominantly of what type of collagen?

Answer 3

Type I collagen

Question 4

What is the most common skeletal dysplasia and a major cause of dwarfism?

Answer 4

Achondroplasia

Question 5

Blue sclerae, skeletal fragility, hearing loss, and dental imperfections are clinical features of what bone matrix disease?

Answer 5

Osteogenesis imperfecta

Question 6

List a few of the pathogenetic factors in the development of osteoporosis.

Answer 6

Age-related changes, reduced physical activity, genetic factors, calcium nutritional state, hormonal influences.

Question 7

Osteitis deformans is also known as _________. What are the three progressive phases of this disease

Answer 7

Paget disease
1) An initial osteolytic stage, followed by
2) A mixed osteoclastic-osteoblastic stage, which ends with a predominance of osteoblastic activity and evolves ultimately into
3) A burnt out quiescent osteosclerotic stage

google:
Paget’s Disease of Bone, also known as osteitis deformans, is a painful disease of bone remodeling. Normally in the body, bone is broken down and built up again on a regular basis. With this disease, bone is broken down more quickly and the new bone that replaces it is more brittle and breaks easily.

Question 8

steitis fibrosa cystica is a lesion that develops in the late stages of what disease?

Answer 8

Severe hyperparathyroidism

Question 9

osteomyelitis is most frequently caused by what organism

Answer 9

Staphylococcus aureus

Question 10

What are the three most serious infections of bone? What is a Brodie abscess?

Answer 10

Pyogenic osteomyelitis, mycobacterial osteomyelitis, skeletal syphilis
Brodie abscess – a small intraosseous abscess that frequently involves the cortex and is walled off by reactive bone

Question 11

Dead bone in association with osteomyelitis is known as a

Answer 11

Sequestrum

Question 12

What are the histologic hallmarks of skeletal syphilis? What is the deformity that occurs in the lower extremity?

Answer 12

Edematous granulation tissue containing numerous plasma cells and necrotic bone; gummata also occur
Syphilitic saber shin

Question 13

The actual tumor of an osteoid osteoma that manifests radiographically as a small round lucency is the

Answer 13

Nidus

Question 14

List some of the benign conditions that precede the development of osteosarcoma, which occurs in the elderly.

Answer 14

Paget disease, bone infarcts, and previous radiation

Question 15

What are the histologic variants of osteosarcoma?

Answer 15

Osteoblastic, chondroblastic, fibroblastic, telangiectatic, small cell, and giant cell

nmenonic/acrotnym GOT CFS

Question 16

What is the histological component common to all types of osteosarcoma?

Answer 16

The formation of bone by the tumor cells is most diagnostic of osteosarcoma

Question 17

What is the most common site of metastasis of an osteosarcoma? What is the typical prognosis of a patient with osteosarcoma?

Answer 17

Lung
Long-term survival is 60-70%

Question 18

What is the risk of developing a chondrosarcoma in an exostosis (osteochondroma)?

Answer 18

Rarely in sporadic cases, but more commonly in those with multiple hereditary exostosis (5% to 20%).

google:
An exostosis is an extra growth of bone that extends outward from an existing bone. Common types of exostoses include bone spurs, which are bony growths also known as osteophytes.

Question 19

Compare Maffucci syndrome to Ollier disease.

Answer 19

Both are nonhereditary disorders characterized by multiple enchondromas. Maffucci syndrome is, in addition distinguished by presence of spindle cell hemangiomas.

note in the attached pic a) Maffucci and c) is ollier

google:

Maffucci syndrome is a disorder that primarily affects the bones and skin. It is characterized by multiple enchondromas (benign enlargements of cartilage), bone deformities, and hemangiomas (tangles of abnormal of blood vessels). The abnormal growths associated with Maffucci syndrome may become cancerous (malignant)

ollier :A rare disorder that causes benign (not cancer) growths of cartilage in the bones. These growths usually occur in the bones of the hands and feet, but they may also occur in the skull, ribs, and spine. They may cause bones to break, to be deformed, or to be shorter than normal.

In Maffucci syndrome, tumors also occur as soft tissue hemangiomas, which are absent in Ollier disease

Question 20

What is the common location for a chondrosarcoma?

Answer 20

Chondrosarcomas commonly arise in the axial skeleton, including the pelvis, shoulder and ribs.

Question 21

What is the age group of patients affected with Ewing sarcoma/PNET? Where does Ewing sarcoma/PNET arise?

Answer 21

Approximately 80% are younger than 20 years. Arises in the medullary cavity

Question 22

Which bones are more likely to be involved in Ewing sarcoma? Which portion of the bone is most likely to be involved?

Answer 22

Ewing sarcoma usually arises in the medullary cavity of the diaphysis of long tubular bones, especially the femur, and the flat bones of the pelvis. Tumor invades the cortex and periosteum and soft tissue.

Question 23

How has the prognosis for a patient with Ewing sarcoma/PNET changed over the years?

Answer 23

The treatment of Ewing sarcoma includes chemotherapy and surgery with or without irradiation. The advent of effective chemotherapy has dramatically improved the prognosis to 75% 5-year survival; and 50% are long-term cures

Question 24

What are the most common joints involved in osteoarthritis? What are Heberden nodes?

Answer 24

Hips, knees, lower lumbar and cervical vertebrae, proximal and distal interphalangeal joints of the fingers, first carpometacarpal joints, and first tarsometatarsal joints.
Heberden nodes (pic in question) are prominent osteophytes at the distal interphalangeal joints, that are common in women (but not men)

Question 25

A chronic systemic inflammatory disorder of autoimmune origin that may affect many tissues and organs but principally attacks the joints, producing a nonsuppurative proliferative.

Answer 25

Rheumatoid arthritis

google:
Inflammation accompanied by pus formation is referred to as suppurating inflammation. In contrast, an inflammation not accompanied or characterized by suppuration is called nonsuppurative inflammation

Question 26

pannus

Answer 26

A mass of edematous synovium, inflammatory cells, granulation tissue, and fibroblasts that grows over the articular cartilage and causes its erosion

google:
type of extra growth in your joints that can cause pain, swelling, and damage to your bones, cartilage, and other tissue. It most often results from rheumatoid arthritis, an inflammatory disease that affects your joints, though other inflammatory diseases are also sometimes to blame.

Question 27

Describe the histological appearance of a rheumatoid nodule.

Answer 27

Rheumatoid nodules have a central zone of fibrinoid necrosis surrounded by a prominent rim of activated macrophages and numerous lymphocytes, and plasma cells

Question 28

What are some of the types of infectious arthritis?

Answer 28

Suppurative arthritis- bacterial infections usually enter the joints from distant sites by hematogeneous spread.

Myobacterial arthritis- a chronic progressive monoarticular infection caused by M. tuberculosis, which occurs in all age groups especially adults.

Lyme arthritis- caused by infection with the spirochete Borrelia burgdorferi, with is transmitted by deer ticks.

Viral arthritis- can occur in the setting of a variety of viral infections including alphavirus, parovirus B19, rubella, Epstein-Barr virus and hepatitis B and C.

Question 29

What is a rhabdomyosarcoma and what are the three subtypes?

Answer 29

A malignant mesenchymal tumor with skeletal muscle differentiation.

Embryonal rhabdomyosarcoma (60%)

Alveolar rhabdomyosarcoma (20%)

Pleomorphic rhabdomyosarcoma (20%)

Question 30

What are the characteristics of a synovial sarcoma?

Answer 30

Synovial sarcoma was so-named because the first described cases arose in the soft tissues near the knee joint and a morphologic relationship to synovium was postulated. However, these tumors can present in locations (chest, wall, head and neck) that lack synovium. Synovial sarcomas account for 10% of all soft tissue sarcomas and most occur in people in their 20s to 40s.

Question 31

what is the histological hallmark of biphasic synovial sarcoma?

Answer 31

A spindle cell component as well as gland-like structures composed of cuboidal to columnar epithelioid cells

Question 32

What is myasthenia gravis and what are some associations with the disease?

Answer 32

Myasthenia gravis is an autoimmune disease that is usually associated with autoantibodies directed against acetylcholine receptors.
It is often associated with thymic hyperplasia or thymoma (malignant (cancer) cells form in the thymus.), frequently involves ocular muscles, and is marked by fluctuating weakness that worsens with exertion.

google:
Myasthenia gravis is a rare long-term condition that causes muscle weakness. It most commonly affects the muscles that control the eyes and eyelids, facial expressions, chewing, swallowing and speaking. But it can affect most parts of the body.

Question 33

List some causes of skeletal muscle atrophy. What is the appearance of myofibers after undergoing atrophy?

Answer 33

Loss of innervation, disuse, cachexia, old age and primary myopathies Flattened, angulated shape.

Question 34

Distinguish between Type I and Type II muscle fibers.

Answer 34

Type I fibers – Red, high mitochondrial density, low glycolytic capacity, high oxidative capacity, Action – sustained force, MYH7 gene expression

Type II fibers – Pale red-tan, low mitochondrial density, high glycolytic capacity, low oxidative capacity,
Action – fast movement, MYH2, MYH4, MYH1 gene expression

Question 35

What is inclusion body myositis and what part of the body is usually involved?

Answer 35

A disease of late adulthood that typically affects patients older than 50 years and is the most common inflammatory myopathy in patients older than age 65 years. Most affected individuals present with slowly progressive muscle weakness that tends to be most severe in the quadriceps and the distal upper extremity muscles.

Question 36

What are the two most common forms of muscular dystrophy?

Answer 36

Duchenne and Becker muscular dystrophy

Question 37

What are the major characteristics of Duchenne muscular dystrophy?

Answer 37

Normal at birth, and early motor milestones are met on time. Walking, however, is often delayed, and the first indications of muscle weakness are clumsiness and inability to keep up with peers. Weakness begins in the pelvic girdle then extends to the shoulder girdle. Pseudohypertrophy of calf muscles is an important clinical finding. Elevated creatine kinase in 1st decade of life. Death results from respiratory insufficiency, pulmonary infection, and cardiac decompensation.

Question 38

Cutaneous pigmentations, also termed _____________macules, are associated with neurofibromatosis.

Answer 38

Café au lait

google:
Café-au-lait spots are light to dark brown pigmented birthmarks that commonly appear on a newborn’s skin. Spots can change in size and number over time. More than six café-au-lait spots can be a sign of an underlying genetic condition like neurofibromatosis type 1

Neurofibromatosis is usually noncancerous. There are three types of this condition. Type 1 usually appears in childhood, while Types 2 and 3 appear in early adulthood.
Type 1 can cause bone deformities, l