Bone Tumors

Question 1

Mucoid degeneration of periarticular tissue
Herniation of connective tissue from joint capsule, tendon sheath, bursae
Filled with clear/gelatinous fluid
TRANSILLUMINATES with pen-light

Answer 1

Ganglionic Cyst

*Mucinous fluid collects via a 1-way valve mechanism

Question 2

Growth presents on Wrist (most common), dorsal foot, and knee

Rubbery, round, well-circumscribed nodule

Transillumination positive

Answer 2

Ganglionic Cyst

*can be removed with Needle aspiration (but recurrence common). Self Resolves.

Question 3

Periosteal elevation (sail sign)

Answer 3

Osteosarcoma

Question 4

Presents with progressive right knee swelling and pain. No history of trauma
Large lytic lesion involving the metaphysis of long bones with extensive soft-tissue swelling.

Answer 4

Osteosarcoma

*must be amputated

Question 5

small, benign, bone-forming tumor that typically occurs in adolescent boys.
Histopathology shows irregular patterns of woven bone lined by a single layer of benign-appearing osteoblasts.

Answer 5

Osteoid osteoma

Question 6

the most common primary bone tumor in children and young adults and typically arises near the metaphyses of long bones

Answer 6

Osteosarcoma

*2nd is Ewing

Question 7

Mesenchymal stem cell neoplasm

Answer 7

Ewing Sarcoma

Question 8

Early metastases to lungs & other bones (may be subclinical or cause Hemoptysis)

Answer 8

Ewing Sarcoma

Question 9

Sheets of uniform, small, round cells separated by fibrous septae

Scant, clear cytoplasm (heavy glycogen content)

Areas of hemorrhage & necrosis

Answer 9

Ewing Sarcoma

Question 10

an uncommon tumor and typically occurs in the 5th or 6th decade of life.

Histology shows neoplastic cells in a hyaline cartilage matrix, usually with small calcifications

Answer 10

Chondrosarcoma

Question 11

a common, benign tumors that arise from the subcutaneous fat and present as soft, mobile masses that are stable or enlarge slowly over time.

histopathology shows well-differentiated, mature adipocytes in lobules with fibrous septa and cap

Answer 11

Lipomas

Question 12

Paget disease of bone is characterized by excessive and disordered bone formation, with focal thickening of ____ and ____ bone.

Features include bone pain, fractures, and arthritis of adjacent joints. Commonly seen at age >50

Answer 12

trabecular

cortical