Soft Tissue and Joint Tumors

Question 1

What are mesenchymal proliferations that occur in the extraskeletal non-epithelialized tissues of the body, excluding the joints, nervous system, hematologic tissue and lymphatic system?

Answer 1

soft tissue tumors

Question 2

What is the name of malignant soft tissue tumors?

Answer 2

sarcomas

Question 3

What is more common, benign or malignant soft tissue tumors?

Answer 3

Benign tumors are 100X more common

Question 4

Where do the majority of soft tissue tumors arise?

Answer 4

thigh (extremities)

Question 5

Tumor-like conditions in joints are most likely due to what?

Answer 5

trauma or degenerative processes

Question 6

What is the name for small (1-1.5cm) ) cyst-like lesions that are almost always located near a joint capsule or tendon sheath?

Answer 6

ganglions

Question 7

True or false: ganglions are highly related to ganglia of the nervous system.

Answer 7

FALSE- they have nothing to do with the nervous system.

Question 8

What exactly is a ganglion?

Answer 8

degenerative phenomenon that leave spaces that are filled with myxoid fluid

Question 9

Where are ganglions most commonly found? What do they feel like?

Answer 9

pea-sized nodule located around the wrist joint

Question 10

Do ganglions have communication with the joint space?

Answer 10

NO

Question 11

What is the slang term for a ganglion? Why is it called this?

Answer 11

Bible bump (called this because when hit hard with heavy book, it goes away)

Question 12

How do you treat a ganglion?

Answer 12

needle aspiration or surgery

Question 13

What tumor-like condition is caused when there is herniation of synovium through a joint capsule or enlargement of a bursa?

Answer 13

synovial cysts

Question 14

What is a Baker cyst?

Answer 14

synovial cyst that forms in the popliteal space in the setting of RA

Question 15

Describe the synovial lining of a Baker cyst.

Answer 15

hyperplastic and contains inflammatory cells/fibrin

Question 16

What is the term for benign neoplasms that develop in the synovial lining of joints, tendon sheaths, and bursae?

Answer 16

Tenosynovial giant cell tumor

Question 17

What are the two types of Tenosynovial giant cell tumor? Where do they most commonly occur?

Answer 17

Diffuse type- involves large joints

Localized type- occurs as a discrete nodule attached to a tendon sheath (commonly in the hand)

Question 18

Who gets tenosynovial giant cell tumors?

Answer 18

young adults in 20s, 30s, 40s

Question 19

What causes tenosynovial giant cell tumors?

Answer 19

chromosomal translocation of a (type VI collagen alpha-3) promoter that turns on synthesis of M-CSF that causes a proliferation of macrophages, some multinucleated, in a manner similar to giant cell tumor of bone.

Question 20

How does the gross appearance of diffuse tenosynovial giant cell tumors differ from the localized counterparts?

Answer 20

Diffuse: normally smooth joint synovium is converted into a tangled mat by red-brown folds, finger-like projections, and nodules
Localized: well circumscribed

Question 21

True of false: neoplastic cells only make up less than 25% of the cells in a tenosynovial giant cell tumor?

Answer 21

TRUE! only 2-16% (polygonal, moderately sized, look like synoviocytes)

Question 22

Where are neoplastic cells found in a nodular tenosynovial giant cell tumor?

Answer 22

grow in solid aggregate that may be attached to the synovium by a pedicle

Question 23

What cell type is in high concentrations in tenosynovial giant cell tumors?

Answer 23

macrophages

Question 24

Where is tenosynovial giant cell tumor most commonly found?

Answer 24

knee

Question 25

What is the most common soft tissue tumor of adulthood?

Answer 25

lipoma

Question 26

What is a lipoma?

Answer 26

benign tumor of fat

Question 27

What is the most common subtype of lipoma? Describe it.

Answer 27

conventional lipoma (well encapsulated mass of mature adipocytes)

Question 28

Where do conventional lipomas usually arise?

Answer 28

subcutis of proximal extremities or trunk

Question 29

What type of lipoma is associated with pain?

Answer 29

angiolipoma

Question 30

Where do liposarcomas most commonly occur?

Answer 30

deep soft tissues of the proximal extremities and in the retroperitoneum

Question 31

What are the three morphologic subtypes of liposarcoma?

Answer 31

1) Well-diferentiated 2) Myxoid 3) Pleomorphic

Question 32

Describe well-differentiated liposarcoma.

Answer 32

adipocytes + scattered atypical spindle cells

Question 33

Describe myxoid liposarcoma.

Answer 33

abundant basophilic extracellular matrix, arborizing capillaries, and primitive cells at various stages of adipocyte differentiation remniscent of fetal fat

Question 34

Describe pleomorphic liposarcoma.

Answer 34

sheets of anaplastic cells, bizarre nuclei, variable numbers of immature adipocytes

Question 35

Amplification of what gene is characteristic of well-differentiated liposarcomas?

Answer 35

12q13-q15 --> MDM2 (potent inhibitor of p53)

Question 36

Amplification of what gene is characteristic of myxoid liposarcomas?

Answer 36

t(12;16) --> MDM2 (potent inhibitor of p53)

Question 37

What type of liposarcomas have a more agressive behavior (metastasize)?

Answer 37

pleomorphic variant

Question 38

What type of liposarcoma has the least aggressive behavior?

Answer 38

well-differentiated

Question 39

What is a self-limited fibroblastic and myofibroblastic proliferation that typically occurs in young adults in the upper extremity, grows “rapidly” over a period of several weeks (or months), and rarely gets larger than 5 cm?

Answer 39

Nodular fasciitis

Question 40

What is commonly present (25%) in patients with nodular fasciitis?

Answer 40

history of trauma

Question 41

What is the mutation commonly seen in nodular fasciitis?

Answer 41

t(17;22) that produces a MYH9-USP6 fusion gene

Question 42

Is nodular fasciitis a neoplasm?

Answer 42

defies classification as a neoplasm because it is clonal, but self-limited

Question 43

True of false: Nodular fasciitis typically spontaneously regresses.

Answer 43

True!

Question 44

What is the name of reactive bone formation in muscle as a result of injury (metaplastic repair response)?

Answer 44

Myositis ossificans

Question 45

What is the cause of myositis ossificans?

Answer 45

blunt trauma (mostly to the lower limb)

Question 46

What is the histiologic pattern of woven bone in myositis ossificans?

Answer 46

well-formed at the periphery but immature at the center

Question 47

What are the two forms of fibromatosis?

Answer 47

superficial and deep

Question 48

Which type of fibromatosis is an infiltrative fibroblastic proliferation that causes local deformity but has an innocuous clinical course?

Answer 48

Superficial

Question 49

What are two examples of superficial fibromatoses involving the hands?

Answer 49

Palmar fibromatosis | Dupuytren Contracture

Question 50

What are two examples of superficial fibromatoses involving the feet?

Answer 50

Plantar fibromatosis | Ledderhose disease

Question 51

What is the name of a fixed flexion contracture of the hand where the fingers bend towards the palm and cannot be fully extended (straightened)?

Answer 51

Dupuytren contracture

Question 52

What fingers are usually involved in Dupuytren contracture?

Answer 52

ring finger and pinky | middle finger in advanced cases

Question 53

Is Dupuytren contracture usually bilateral or unilateral?

Answer 53

50% bilateral | 50% unilateral

Question 54

What really is a fibromatosis?

Answer 54

benign soft tissue tumor

Question 55

What is Peyronie disease?

Answer 55

a palpable induration or mass (penile fibromatosis) on the dorsolateral aspect of the penis

Question 56

What are complications of Peyronie disease?

Answer 56

abnormal curvature of the shaft, constriction of the urethra, or both

Question 57

What are examples of deep fibromatoses?

Answer 57

Desmoid tumors | Aggressive Fibromatoses

Question 58

Do deep fibromatoses metastasize?

Answer 58

NO

Question 59

How common are deep fibromatoses?

Answer 59

RARE

Question 60

Where do deep fibromatoses occur?

Answer 60

musculoaponeurotic structures of the anterior abdominal wall

Question 61

What is the cause of deep fibromatoses?

Answer 61

mutations in the APC or beta-catenin genes--> cause increased Wnt signaling

Question 62

What two groups of patients are predisposed to deep fibromatoses?

Answer 62

Gardner syndrome (familial adenomatous polyposis) Germline APC mutations

Question 63

The histology of a deep fibromatoses resembles what?

Answer 63

a scar!

Question 64

How might you treat a deep fibromatosis?

Answer 64

cyclooxygenase 2 inhibitors, tyrosine kinase inhibitors, or hormonal blockade (with tamoxifen) SURGERY is difficult because of the extent of infiltration.

Question 65

Do deep fibromatoses invade?

Answer 65

NO- they infiltrate

Question 66

What is a tumor of mesenchymal cell origin composed of malignant fibroblasts in a collagen background?

Answer 66

fibrosarcoma

Question 67

What is the word used to describe the fascicles of tumor cells oriented at alternating acute angles in fibrosarcoma?

Answer 67

"Herringbone" pattern

Question 68

What do fibrosarcoma tumor cells look like?

Answer 68

spindle shape with pointed ends (more or less).

Question 69

True or flase: because fibrosarcomas are derived from fibroblasts, the tumors are made of vast amounts of mature collagen.

Answer 69

FALSE: demonstrate relatively little mature collagen

Question 70

True or false: fibrosarcomas are painful.

Answer 70

True

Question 71

Where do fibrosarcomas occur in bone?

Answer 71

metaphysis of long bones and pelvis.

Question 72

Where do fibrosarcomas occur in soft tissue?

Answer 72

thigh

Question 73

What is a a non-cancerous growth of dermal dendritic histiocytic cells?

Answer 73

Dermatofibroma

Question 74

What might trigger a dermatofibroma?

Answer 74

site of minor injury (insect bite or thorn prick)

Question 75

Where do dermatofibromas most commonly form?

Answer 75

arms and legs

Question 76

What happens when you squeeze a dermatofibroma?

Answer 76

it forms a dimple (indicating tethering of the skin to the underlying fibrous tissue)

Question 77

What is a relatively uncommon soft tissue neoplasm with intermediate- to low-grade malignancy?

Answer 77

Dermatofibrosarcoma protuberans (DFSP)

Question 78

What subcutaneous fibrohistiocytic cellular proliferation is neoplastic and highly malignant?

Answer 78

undifferentiated pleomorphic sarcoma

Question 79

Where do UPS's commonly arise?

Answer 79

deep soft tissues of the extremity, especially the thigh of middle aged or older adults Can arise in retroperitoneum

Question 80

Where do UPS's commonly metastasize?

Answer 80

Lung (90%) Bone (8%) Liver (1%)

Question 81

What is a malignant mesenchymal tumor with skeletal muscle differentiation?

Answer 81

Rhabdomyosarcoma

Question 82

What are the 3 subtypes of Rhabdomyosarcoma?

Answer 82

1) Alveolar (20%) 2) Embryonal (60%) 3) Pleomorphic (20%)

Question 83

Which type of rhabdomyosarcoma is more common in adults?

Answer 83

Pleomorphic rhabdomyosarcoma

Question 84

True or false: rhabdomyosarcomas arise from mature, terminally differentiated muscle cells.

Answer 84

FALSE! (reinforced by the fact that pediatric forms arise in places that do not contain much skeletal muscle like head/neck, sinuses, GU tract)

Question 85

What type of rhabdomyosarcoma frequently contains fusions of the FOXO1 gene to either the PAX3 or the PAX7 gene, rearrangements marked by the presence of (2;13) or(1;13) translocations, respectively?

Answer 85

Alveolar

Question 86

What does the PAX3-FOXO1 fusion protein do in alveolar rhabdomyosarcoma?

Answer 86

interferes with the gene expression program that drives skeletal muscle differentiation

Question 87

What is the name for benign tumors of smooth muscle?

Answer 87

Leiomyoma

Question 88

What is the most common site of leiomyoma?

Answer 88

uterus

Question 89

Why do uterine leiomyomas tend to regress after menopause?

Answer 89

they are estrogen sensitive

Question 90

From what muscle may leiomyomas also arise?

Answer 90

erector pili muscles

Question 91

What are features of hereditary leiomyomatosis and renal cell cancer syndrome?

Answer 91

AD disease Multiple cutaneous leiomyomas Uterine leimyomas renal cell carcinoma

Question 92

What is the cause of hereditary leiomyomatosis and renal cell cancer syndrome?

Answer 92

germline loss-of-function mutation in the fumarate hydratase gene located on chromosome 1q42.3

Question 93

What do soft tissue leiomyomas look like microscopically?

Answer 93

fascicles of densely eosinophilic spindle cells that tend to intersect each other at right angles

Question 94

Where do Leiomyosarcoma most commonly develop?

Answer 94

the deep soft tissues of the limbs and retroperitoneum

Question 95

What is a very lethal site of leiomyosarcomas?

Answer 95

IVC (or other great vessels)

Question 96

Leiomyosarcomas immunostain with what antibodies?

Answer 96

antibodies to SM actin and desmin

Question 97

How do sarcomas spread?

Answer 97

blood (hematogenous spread)

Question 98

Where is a very common site of metastasis for sarcomas?

Answer 98

LUNGS (capillary beds are rich there and filter them out--allowing htem to grow in lung tissue)

Question 99

In what part of the lungs are pulmonary mets from sarcomas most common?

Answer 99

basal lower lobes