Bone tumors, Joints & Soft tiss Path

Question 1

Osteochondroma

Answer 1

aka exostosis
Most common benign bone tumors.
Men are 3x more likely & 85% are early adulthood. Targets metaphysis. Exostosis is sessile/pedunculated and continuous with medullary cavity.

Question 2

Multiple hereditary exostosis

Answer 2

AD form of osteochondroma with 5-20% of cases progressing to CHONDROSARCOMA (EXT gene)

Question 3

What are enchondromas?

Answer 3

Enchondromas are within the medullary cavity or on surface (subperiosteal or juxtacortical)
Well circumscribed nodules of hyaline cartilage encased in reactive bone

Question 4

Difference between Ollier syn. v Maffucci syn.?

Answer 4

Both are characterized by multiple enchondromas with incr. cellulart atypia.

Difference: Maffucci syn. also has angiomas, incr. risk of chondroSARCOMA & other malignancies.

Question 5

Chondrosarcoma

Target pop., body region affected & imaging?

Answer 5

Second most common malignant matrix producing tumor of bone. Male predominance in 40’s+. Affects axial skeleton (SHOULDERS). Grade 3 spreads hematogenously (LUNGS).
Imagining: Flocculent & Fast growing

Question 6

Osteosarcoma

Target pop., gene assoc., imaging?

Answer 6

Most common primary malignant tumor of bone. PAINFUL.
Bimodal age of <20 yo males around knee or older males with Pagets & prior radiation. Rb gene incr risk. p53 mut. ->Li Fraumani syn. (breast cancer)
Spreads hematogenously to LUNGS.
Imaging shows mixed lytic & blastic mass SUNBURST PATTERN

Question 7

Osteoid osteoma

Character, size, tx and histo?

Answer 7

Painful! Worse at night but responds to aspirin and NSAIDs. <2cm with central nidus surrounded by rim of osteoblasts. Thick rind of reactive cortical bone
Tx with radiofreq. ablation

Question 8

Osteoblastoma

size and area affected?

Answer 8

Painful. >2cm usually involving the spine. NO bony reaction & DOES NOT respond to aspirin. Tx is excision

Question 9

If pt has elevation of periosteum, what is this sign called and what tumor is it pathognomonic for?

Answer 9

Codman triangle -> osteosarcoma

Sunburst pattern may also be seen

Question 10

Ewing Sarcoma Family Tumors (ESFT)

Target pop., Gene affected, histo & clinical appearance?

Answer 10

<20 yo whites. 2nd most common bone sarcoma in children. t(11;22)(q24:q12) fusion gene EWS-FL11 SMALL BLUE ROUND CELL TUMOR with neural diff and primitive neuroectodermal tumor (PNET).
Masses are tender, warm, swollen (fever & incr ESR) - looks like infection!
Femurs and other long bones affected.
Imaging shows periosteal rxn - LAMELLATED “onion-skin”

Question 11

Fibrous dysplasia

What is the dz? Do majority of cases involve multiple bones? Target pop? Bones affected in dz? Radiograph findings?

Answer 11

Benign proliferation of fibrous tiss. & bone that does not mature.
Majority monostotic & usually asymptomatic.
Early adolescence with 1/3 affecting craniofacial bones, 1/3 affecting femur or tibia, 1/3 affecting ribs.
Ground glass appearance with well defined margins. Curvilinear trabeculae aka “Chinese characters” on histo.

Question 12

Dx the pt.: 8 yo female pt presents to the clinic with her mom after she noticed her developing pubic hair and breasts. You notice the child has unilateral cafe au lait skin lesions and after x-rays that the same side of her body has some bone lesions

Answer 12

McCune-Albright Dz a type of fibrous dysplasia

GNAS mut.

Question 13

What is Mazabraud syn? What demographic do you see the dz in?

Answer 13

A subtype of fibrous dysplasia seen in children. Usually polyostotic, causes mult. skeletal deformities and myxomas

Question 14

Dx pt.: You are sent a path slide of bone with multinucleated giant cells. The attending physician says the pt is 20-40 yo and the lesion was fast growing. It was taken from the epiphyses of the distal femur and found when the pt thought they had arthritis in that knee.

Answer 14

Osteoclastoma

Benign but aggressive. found at knee with arthritis like symptoms. Tend to reoccur after curettage

Question 15

T or F

Most cancers of the bone are 1°

Answer 15

FALSE

Metastatic tumors are the most common form of skeletal malignancy

Question 16

What are the 4 most common cancers in adults that metastasize to bone?

Answer 16

PROSTATE, breast, kidney & lung

Ex. Prostatic adenocarcinoma is blastic (bone forming)

Question 17

What are the 5 most common cancers in kids that metastasize to bone?

Answer 17

neuroblastoma, Wilms, osteosarcoma, Ewing & rhabdomyosarcoma

Question 18

Lung, kidney, and colon cancer like to spread to what bones?

Answer 18

Small bones -> hands and feet

Question 19

RA or Osteoarthritis?
Women (3:1) in the 2nd-4th decade
Dz of synovium
Autoimmune, inflammatory
symmetrical polyarthritis
Affects small joints of the hands and feet
Worse in the morning & with rest
Sx: Fatigue, fever & night sweats

Answer 19

Rheumatoid Arthritis!

Pannus formation in joint, bony fibrosis and inflammation also present (not seen in OA)
MORNING STIFFNESS
RF (+) & CCP (+)

Question 20

RA or Osteoarthritis?
Usually occurs later in life
Dz of cartilage
Initially asymmetrical monoarthritis -> polyarthritis
Weight bearing joints (knees and hips)
Stiffness at the end of the day, worse with use

Answer 20

Osteoarthritis aka degenerative joint dz
A dz of cartilage “Wear & Tear” as a person ages. Incr >50yo with 40% affected >70yo

Women usually have hands and knees effected where men usually have their hips.

Question 21

Where are Bouchard nodes?
Heberden nodes?
What dz are they associated with?

Answer 21

B - Proximal interphalangeal joint
H - Distal interphalangeal joint
Osteoarthritis!

Question 22

4 joint changes in progressive osteoarthritis? (Think what happens to the cartilage, bone and new developments?)

Answer 22

Hunks of cartilage slough (Joint mice)
Subchondral bone is exposed and rubbed smooth (eburnation)
Subchondral cysts develop
Osteophytes form (bone spurs)

Question 23

Rheumatoid Arthritis deformities of hands (4)

Answer 23

Boutonniere - hyperextension of DIP, flexion of PIP
Swan-neck - hyperextension of PIP, flexion of DIP
Ulnar deviation fingers - Decr. junctional space, periarticular bony erosions
Radial deviation of the wrist

Question 24

Rheumatoid Arthritis Pathology (3)

Answer 24

Pannus - edematous, thickened, hyperplastic synovium.
Synovial hypertrophy with villi
Lymphoid aggregates

Question 25

Ankylosing Spondylitis

Answer 25

Autoimmune, T-cell response. Pathologic changes in ligamentous attachments (not synovium). Vertebrae and sacroiliac joints are effected in their 20’s-30’s
RF (-) but HLA-B27 associated

Question 26

Reactive arthritis

Answer 26

Triad of arthritis, urethritis or cervicitis & conjunctivitis (can’t see, can’t pee, can’t climb a tree!)
HLA-B27 associated. Men 20’s-30’s with HIV and prior GI or GU infection.
Associated symptoms - Cardiac conduction abn & aortic regurg.

Question 27

Enteritis assoc. Arthritis

Answer 27

Yersinia, Salmonella, Shigella, Campylobacter causative agents.

Question 28

Psoriatic Arthritis

Answer 28

HLA-B27 with “Pencil in cup deformities”

Question 29

Infectious arthritis

Answer 29

microorganisms seed joints hematogenously. Rapid joint destruction -> permanent deformities

Question 30

Suppurative arthritis and causative agents.

Answer 30

<2 yo H. influ arthritis
Older kids and adults - N. GONOCOCCUS or Staph aureus.
Mycobacterial - gradual progressive pain (hip>knee>ankle).
Lyme dz - Borrelia burgdorferi with skin lesions.
Viral: HIV, HBV, HCV, EBV, Parvo, rubella
Single acutely painful, swollen joint. Jt aspiration is diagnostic, purulent fluid.

Question 31

Gout crystal types? Plasma levels? Age and predispositions (4)?

Answer 31

Monosodium urate (MSU) crystals form in peripheral joints - 1st metatarsal (lower temp.)
Plasma levels >6.8mg/dl
Age is usually 20-30 yr
Genetic predisposition 
Heavy alcohol consumption
Obesity
Drugs (thiazide diuretics)
NOT BIREFRINGENT

Question 32

Pseudo-Gout

Answer 32

aka Chondrocalcinosis aka Ca2+ Pyrophosphate crystal deposition (CPPD)
>50yo. Crystals are chalky white friable deposits. Histo: oval blue-purple aggregates.
POS BIREFRINGENT

Question 33

3 types of cysts

Answer 33

Ganglion cyst - usually wrist, translucent, lacks cell lining, result of cystic or myxoid degen.
Synovial cyst - herniation of synovium
Baker cyst - in popliteal space, RA

Question 34

What is the most common benign soft tissue tumor of adults?

Answer 34

Lipoma

Question 35

Liposarcoma

Answer 35

Common malignant soft tiss tumor in adults (50-60) of proximal extremities & retroperitoneum. 12q13-q15 & t(12;16) -> inhibits p53.
Reocur locally & repeatedly if not completely excised. Myxoid is the most common.

Question 36

Nodular fasciitis

Answer 36

self-limited firboblastic & myofibroblastic prolif. Young adults in upper extremity. Spontaneously regresses

Question 37

Fibromatoses

Answer 37

M>F
Palmer: Dupuytren contracture.
Plantar
Penile: Peyronie Dz

Question 38

Desmoid tumor

Answer 38

aka deep fibromatosis
women and teens in 30’s
Ex. Gardner syn. (familial adenomatous polyposis)

Question 39

Rhabdomyosarcoma
Subtypes (3) and areas of growth

Answer 39

Malignant tumor of kids.
Embryonal subtype (60%) - Rhabdomyoblasts, sarcoma botryoides (cambium layer)
Pleomorphic (20%) - adults
Alveolar subtype (20%)- FOX01 fusion to PAX3 or 7
Grows in cavities - sinuses, head & neck, GU tract.

Question 40

Leiomyoma

Answer 40

Benign smooth muscle tumor of the uterus aka a fibroid. Majority of cases are found in women.

Associated with Hereditary Leiomyomatosis & Renal Cell Cancer syn. is AD with multi cutaneous leiomyomas, uterine leiomyomas and RCC

Question 41

Leiomyosarcoma

Answer 41

Soft tiss sarcomas. Adults w>m affecting extremities and retroparitoneum. Metz to lungs

Question 42

Synovial sarcoma

Answer 42

4th most common sarcoma in 20’s-40’s.

(+) for keratins epith markers. Lung mets common