What is the most common soft tissue tumor?
How are they characterized on histology?
Watch for lipoblasts.
What imaging methods exist to evaluate bone tumors?
X-ray, whole body bone scan, CT, MRI, and PET.
When identifying a bone lesion, what serum tests may be useful, and for the detection of what?
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)
Describe the findings seen in multiple myeloma.
Hypergammaglobulinemia (IgG), lytic lesions throughout the bone marrow, resulting in pathologic fracturing.
Histology: "Sheets of plasma cells with atypical cell features"
A B-cell lymphoma will be positive for what antigen?
CD20 (presumably CD19, 21 as well)
What is the bone tumor pictured here?
Osteosarcoma (note ill-defined borders, and codman's triangle)
Where are osteosarcomas most common?
Distal femur or proximal tibia
Lung cancers may metastasize to bone. What is the most common form seen in women and nonsmokers?
What markers is it positive for?
Positive for TTF1, Cytokeratin.
What benign bone/cartilage tumors are seen in children?
What malignant bone/cartilage tumors?
Osteochondroma, Enchondroma, UBC/ABC.
Osteosarcoma and Ewing Sarcoma.
What is a unicameral bone cyst? Describe its structure, location and composition.
What symptoms does it cause?
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)
Distinguish an Aneurysmal Bone Cyst (ABC) from a Unicameral Bone Cyst (UBC).
Aneurysmal bone cysts are painful, and are filled with blood rather than clear fluid.
(Same group of patients, same bones)
How are UBCs and ABCs treated?
How are Giant cell tumors treated?
Curettage (basically, scraping or scooping)
Also curettage! Same for osteoid osteoma and osteoblastoma.
What marker is displayed?
What is the characteristic genetic aberration?
What is desmoid fibromatosis?
Formation of locally aggressive (but not metastatic) fibromas. Resection usually results in recurrence.
What does a high level of pleomorphism in a sarcoma mean for the treatment course and outlook?
Same as any other cancer: Treat more aggressively (eg with radiation); worse prognosis.
A cartilaginous tumor is invading bone space. What is on the differential?
Histology reveals destruction of bony matrix. What's the most likely diagnosis.
Enchondroma, osteochondroma, chondrosarcoma.
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.
Giant cell tumor (epiphyseal)
Osteoid Osteoma (responded to aspirin)
Chondrosarcoma (old fogie)