Bone, Cartilage, & Soft Tissue Tumors CC - King

Question 1

What is the most common soft tissue tumor?

How are they characterized on histology?

Answer 1

Lipoma

Watch for lipoblasts.

Question 2

What imaging methods exist to evaluate bone tumors?

Answer 2

X-ray, whole body bone scan, CT, MRI, and PET.

Question 3

When identifying a bone lesion, what serum tests may be useful, and for the detection of what?

Answer 3

Serum protein electrophoresis or free light chain tests will reveal certain marrow cancers (myeloma, plasmacytoma)

Prostatic specific antigen will hint at the presence of a prostate adenocarcinoma (presumably, this could could metastasize to bone)

Question 4

Describe the findings seen in multiple myeloma.

Answer 4

Hypergammaglobulinemia (IgG), lytic lesions throughout the bone marrow, resulting in pathologic fracturing.

Histology: “Sheets of plasma cells with atypical cell features”

Question 5

A B-cell lymphoma will be positive for what antigen?

Answer 5

CD20 (presumably CD19, 21 as well)

Question 6

What is the bone tumor pictured here?

Answer 6

Osteosarcoma (note ill-defined borders, and codman’s triangle)

Question 7

Where are osteosarcomas most common?

Answer 7

Distal femur or proximal tibia

Question 8

Lung cancers may metastasize to bone. What is the most common form seen in women and nonsmokers?

What markers is it positive for?

Answer 8

Lung adenocarcinoma.

Positive for TTF1, Cytokeratin.

Question 9

What benign bone/cartilage tumors are seen in children?

What malignant bone/cartilage tumors?

Answer 9

Osteochondroma, Enchondroma, UBC/ABC.

Osteosarcoma and Ewing Sarcoma.

Question 10

What is a unicameral bone cyst? Describe its structure, location and composition.

What symptoms does it cause?

Answer 10

Unicameral bone cysts occur in long-bone metaphyses (eg femur, humerus), are filled with fluid and lined with a fibrous membrane.

Because of cortical erosion, fractures through the cyst are common (may be filled with hemosiderin and granulation tissue)

Question 11

Distinguish an Aneurysmal Bone Cyst (ABC) from a Unicameral Bone Cyst (UBC).

Answer 11

Aneurysmal bone cysts are painful, and are filled with blood rather than clear fluid.

(Same group of patients, same bones)

Question 12

How are UBCs and ABCs treated?

How are Giant cell tumors treated?

Answer 12

Curettage (basically, scraping or scooping)

Also curettage! Same for osteoid osteoma and osteoblastoma.

Question 13

Ewing’s Sarcoma

What marker is displayed?

What is the characteristic genetic aberration?

Answer 13

Ewing’s Sarcoma

CD99

t(11;22)

Question 14

What is desmoid fibromatosis?

Answer 14

Formation of locally aggressive (but not metastatic) fibromas. Resection usually results in recurrence.

Question 15

What does a high level of pleomorphism in a sarcoma mean for the treatment course and outlook?

Answer 15

Same as any other cancer: Treat more aggressively (eg with radiation); worse prognosis.

Question 16

A cartilaginous tumor is invading bone space. What is on the differential?

Histology reveals destruction of bony matrix. What’s the most likely diagnosis.

Answer 16

Enchondroma, osteochondroma, chondrosarcoma.

Chondrosarcoma.

Question 17

Diagnose the following tumors (hint: none are secondary lesions):

12y/o patient with mass in femoral epiphysis.

15/yo patient with pathological fracturing of distal phalanx.

Mass in arm, painful at night but better with aspirin.

80y/o patient with femoral mass, high pleomorphism on biopsy.

Answer 17

Giant cell tumor (epiphyseal)

Enchondroma (fingers)

Osteoid Osteoma (responded to aspirin)

Chondrosarcoma (old fogie)