Bone Pathology

Question 1

Osteomyeltis pathology

Answer 1

Necrotic bone tissue where lacunae are empty

Lytic- lesion that resembles neoplasm on X-ray

Question 2

Common wrist fracture in older adults of distal radius with dorsal angulation of distal fragment from trauma
Dinner fork deformity

Answer 2

Colles’ fracture

Question 3

C2 cervical vertebra is pushed forward due to fracture of posterior elements
Associated with anterior subluxation of body of C2 on C3
Hyperextension

Answer 3

Hangman’s fracture

Question 4

An unusual completely transverse fracture with no jagged edges or fragments at perfect right angle

Answer 4

Chalkstick fracture- usually seen in Paget’s disease and ankylosing spondylitis

Question 5

Bone most often fractured at medial orbit wall and orbital floor, may entrap rectus muscle to get diplopia or detached retina associated

Answer 5

Blow out fracture

Question 6

A common fracture-dislocation of ankle that involved fractures of medial and lateral malleoli
Distal tibia or fibula may also be additionally fractured
Postero-lateral dislocation

Answer 6

Pott’s fracture

Question 7

Child’s hip joint, pain and limp there, loss of blood supply to femoral head (ischemic necrosis), unknown cause, subcritical fracture or fracture of epiphysis may be associated
Leads to osteoarthritis

Answer 7

Legg-calve-perthes disease

Question 8

Fracture healing events- the fracture callus

Answer 8

Hemorrhage leading to hematoma contained in periosteum
Inflammatory cells attracted by soluble mediators of hematoma, damaged vessels and dying bone
Osteoclasts activated to remove necrotic bone
Granulation tissue is laid down
Soft callus forms containing fibrous tissue, osteoblasts and some woven bone is laid down
Hard callus forms with more woven bone, bridging fracture line and increasing calcification
Woven bone remodeled by lamellar bone

Question 9

Benign, solitary, slow-growing lesion in skull and facial bones of middle aged adults
Associated with Gardner syndrome, familial adenomatous polyposis, epidermal cysts, and fibromatosis

Answer 9

Osteoma

Question 10

Adolescents, causes nocturnal pain, the tumor constitutes the nidus (origination- see a lot of woven bone) and elicits extensive surrounding sclerosis of bone around it
Smaller than an osteoblastoma
Appendicular skeleton
Widening and lucency in cortex on X-ray

Answer 10

Osteoid osteoma

Question 11

High grade intramedullary malignant tumors in distal femur/proximal tibia
Permeation and destruction of bone with extension into adjacent soft tissue, raising the periosteum, and formation of Codman triangle
Often have nodes of metastasis- lungs, vertebral column
Large nuclei/mitotically active cells that lays down malignant osteoid
Can produce cartilage

Answer 11

Osteosarcoma

Question 12

Cartilaginous tumor in 20-40 year olds, medulla of tubular bones of hands and feet
Can be isolated abnormality (Ollier disease) or associated with hemangiomatosis, ovarian carcinoma, brain glioma
Same ratio in males and females
Disorganized, but not atypical chondrocytes

Answer 12

Enchondroma

Question 13

AKA exostosis
Benign, EXT1/EXT2 mutations
Cartilage caps a bony stalk, arises near growth plate

Answer 13

Osteochondroma

Question 14

Axial skeleton, arisen in pre-existing cartilaginous lesions, low-grade
Can infiltrate the cortex
More than one nucleus in lacunae space
Larger cells

Answer 14

Chondrosarcoma

Question 15

Developmental arrest tumor
Monostotic in medulla of bones of adolescents
Polyostotic without endocrine dysfunction (unlike McCune-Albright syndrome)
Females higher ratio than males
Fibrous tissue looks like its arising from connected trabeculae

Answer 15

Fibrous dysplasia

Question 16

Unknown histogenesis bone tumor
Occurs in medulla of diaphysis of long tubular bones and pelvic flat bones
Destructive lytic tumor with onion-skin periosteal reaction
Round nuclei and little cytoplasm, look like lymphocytes, stain strongly with Cd99 antibody

Answer 16

Ewing sarcoma

Question 17

Bone tumor of uncertain histogenesis, middle-aged adults, arise around knee and epiphysis is always involved, lytic lesion that invades cortex and forms soft tissue mass, more in females than males
Multinucleated giant cells

Answer 17

Giant cell tumor

Question 18

Metastatic prostate cancer is usually:

Answer 18

Blastic

Question 19

Renal cell carcinoma is usually:

Answer 19

Lytic

Question 20

Breast and lung cancers are:

Answer 20

Mixed- blastic and lytic

Question 21

Most common metastatic tumors in children

Answer 21

Neuroblastoma, osteosarcoma, Ewing sarcoma, rhabdomyosaroma

Question 22

Malignant soft tissue tumor
Microscopic appearance resembles skeletal muscle
Most common soft tissue sarcoma of children
Occurs at increase rate in Li-Fraumeni syndrome (inherited mutation in p53 tumor suppressor gene)
Elongated clusters of tumor called strap cells

Answer 22

Rhabdomyosarcoma (can also be named for specific microscopic appearance that it resembles- liposarcoma, leiomyosarcoma)

Question 23

Benign soft tissue tumor

Answer 23

Rhabdomyoma