10. Pathology and Oncology MCQs

The bone scan reveals lesions throughout the skeleton. The patient’s age, gender, and pain pattern are consistent with metastatic prostate cancer. Multiple myeloma typically does not have enough osteoblastic activity to produce this bone scan. The patient’s age is not consistent with metastatic neuroblastoma (a pediatric disease). Polyostotic fibrous dysplasia may involve multiple active lesions in younger patients but does not have such a widespread distribution of lesions. Hodgkin’s lymphoma can involve bone, but the widespread discrete appearance on this bone scan is most consistent with metastatic prostate cancer. In a patient with widespread bone metastases from prostate cancer, bisphosphonates may play a critical role in treatment by decreasing pain and the number of fractures.

While guidelines for predicting fracture risk are at best imprecise, the scoring system by Mirels (pain, anatomic location, and pattern of bony destruction) has been shown to be most predictive of fracture risk. Functional pain, peritrochanteric location, and lytic bone destruction are the greatest risk factors for pathologic fracture. The factors of patient weight, age, soft-tissue mass, and location within bone are all of lesser importance.

Discussion: Osteosarcoma is the most common primary malignant tumor of bone in childhood, followed by Ewing’s sarcoma. Rhabdomyosarcoma is a soft-tissue sarcoma of childhood. Chondrosarcoma rarely occurs in childhood.

The radiograph shows a benign-appearing cortically based lesion eroding the underlying cortex, producing a saucer-shaped defect typical of a periosteal chondroma. The histology shows benign-appearing neoplastic cartilage. Although enchondroma would have the same histologic appearance, radiographs generally show a lesion with a central medullary epicenter. The benign-appearing histology does not support chondrosarcoma. Chondromyxoid fibroma will generally show histologic elements of its fibrous and myxoid components. Chondroblastoma typically demonstrates histologic findings of polyhedral cells separated by a chondroid matrix with pericellular, lattice-like “chicken wire” calcification.

Osteoid osteomas are most common in adolescent patients and in boys. The significant inflammatory response to this tumor is presumed to be secondary to high levels of prostaglandin production. Characteristic pain at night is relieved by aspirin or NSAIDs.

The patient has changes consistent with radiation therapy to the femur, including osteopenia and an aggressive appearing neoplasm. The tumor is most likely a radiation-induced sarcoma. This is more likely than recurrent lymphoma at this late date.

Slide 1 Slide 2A 20-year-old woman has a large mass over the right hip. An anteroposterior and oblique radiographs are shown in Slides 1 and

Although factors such as a high-grade tumor and large size are associated with decreased survival, the presence of metastases carries the worst prognosis. Good results are very rare when metastases are present. Soft-tissue sarcomas, as a whole, respond poorly to chemotherapy, leading to a poor prognosis when metastases are present.

The indications of bisphosphonate therapy in breast cancer patients range from the correction of hypercalcemia to the prevention of cancer treatment-induced bone loss. Bisphosphonates reduce metastatic bone pain in at least 50% of patients and can reduce the frequency of skeletal-related events by 30% to 40%. Osteonecrosis of the jaw could occur in up to 2.5% of breast cancer patients during long-term bisphosphonate therapy.

The main consequence of tumor invading the bone is activation of both osteoblasts and osteoclasts. However, the osteoclastic effect predominates in the majority of tumors early after the invasion of bone by tumor cells, causing resorption of bone.

DISCUSSION: The most common site of metastases from a soft-tissue sarcoma is the lungs and occurs in 40% to 60% of patients. The second most common site of metastases in soft-tissue sarcomas is the lymph nodes. Nodal metastases are seen with regularity in synovial sarcoma, epithelioid sarcoma, and rhabdomyosarcoma. The liver, brain, bone, and muscle are occasional sites of spread, but the occurrence is very rare. REFERENCES: Simon SR (ed): Orthopaedic Basic Science. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1994, pp 219-276. Menendez LR (ed): Orthopaedic Knowledge Update: Musculoskeletal Tumors. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 255-259.

DISCUSSION: The radiographs reveal phleboliths on the volar side of the forearm consistent with hemangioma. The MRI scan reveals a rather well-circumscribed in size, irregular in shape, intramuscular soft-tissue mass in the volar aspect of the distal right forearm within the flexor group musculature. The mass demonstrates heterogeneous mixed signal intensity in both T1- and T2-weighted sequences with increased signal intensity on the T1, suggesting fat within the tumor, typical of hemangioma. The postgadolinium-enhanced sequences demonstrate heterogeneous enhancement. The MRI findings are consistent with a soft-tissue hemangioma. REFERENCES: Garzon M: Hemangiomas: Update on classification, clinical presentation and associate anomalies. Cutis 2000;66:325-328. Kurkcuoglu IC, Eroglu A, Karaoglanoglu N, et al: Soft tissue hemangioma is a common soft tissue neoplasm. Eur J Radiol 2004;49:179-181.

The history, imaging and pathology points to chondrosarcoma as the diagnosis, and therefore wide resection and reconstruction is the most appropriate treatment. Chondrosarcoma tends to occur in an older individuals and the most common sites of origin are the femur, tibia, humerus, ribs, scapula then pelvis. Chondrosarcomas grow slowly and patients present with dull aching pain. X-rays typically have a subtle, radiolucent, permeative lesion or may have hazy or speckled calcifications with either a diffuse "salt & pepper" pattern or a more discrete "popcorn" pattern. The MRI defines the amount of marrow and soft-tissue involvement, and typically has high T2 signal intensity. Bone scintigraphy will be positive. In pathological sections, low-power imaging demonstrates lobulated clusters of chondrocytes, and high-power imaging demonstrates a bland cellular appearance, extensive basophilic cytoplasm, and no mitotic figures (low grade chondrosarcoma).

DISCUSSION: Ewing’s sarcoma is the second most common bone tumor in children with an incidence of three per one million Caucasian children younger than 21 years of age. Ewing’s sarcoma is rare in African Americans. Osteosarcoma is the most common bone tumor in children. Rhabdomyosarcoma is the most common soft-tissue sarcoma in children. Fibrosarcoma is a rare primary bone tumor most commonly seen in adults. Adamantinoma is a rare primary bone malignancy also most commonly seen in adults in the tibia. REFERENCES: Menendez LR (ed): Orthopaedic Knowledge Update: Musculoskeletal Tumors. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, p 195. Gibbs CP Jr, Weber K, Scarborough MT: Malignant bone tumors. Instr Course Lect 2002;51:413-428.

These are classic findings of osteonecrosis of the hip. The radiograph reveals the subchondral sclerotic pattern commonly seen in osteonecrosis and is quite extensive in this patient. The MRI scan reveals the typical serpentine-like region of low signal intensity with a central zone where the signal is similar to fat.

The radiographs reveal osteonecrosis with collapse. The most reliable and durable treatment for osteonecrosis of the humeral head remains prosthetic shoulder arthroplasty. Osteonecrosis of the humeral head may be seen after the use of steroids, and there is an increasing demand for shoulder arthroplasty in young people because of the use of high-dose steroids in chemotherapy regimes for the treatment of malignant tumors. The indications for most shoulder arthrodeses today include posttraumatic brachial plexus injury, paralytic disorders in infancy, insufficiency of the deltoid muscle and rotator cuff, chronic infection, failed revision arthroplasty, severe refractory instability, and bone deficiency following resection of a tumor in the proximal aspect of the humerus. Clearly, the role of arthroscopy and related minimally invasive techniques in the treatment of humeral head osteonecrosis remains unknown.

The most common bone tumor in the hand is an enchondroma. Forty-two percent of these lesions occur in the small tubular bones. They frequently present with a fracture in these locations. Fractures are usually treated nonsurgically. Indications for surgery include patients with symptomatic lesions or those who are considered high risk for recurrent fracture. The histologic appearance of an enchondroma in the hand is more cellular than enchondromas found in the long bones.

The grading of response to chemotherapy for osteosarcoma was introduced by Huvos and associates. Patients with tumors that show more than 90% necrosis after neoadjuvant chemotherapy are considered to have had a good response and have better survival rates than those with less than 90% necrosis. More recently, similar results have been reported in patients with Ewing sarcoma. Chemotherapy is not typically used for giant cell tumor of bone.

These lesions are extremely vascular and can cause uncontrolled intraoperative bleeding; therefore embolization is the appropriate first treatment. Because the radiograph and CT scan show a lytic lesion in the supra-acetabular region that affects the weight-bearing dome and medial wall, the next step in treatment would most likely be a total hip arthroplasty and acetabular reconstruction. Treatment with bisphosphonates and radiation therapy will not prevent an acetabular fracture.

Tumoral calcinosis is a heritable condition characterized by periarticular metastatic calcification. Most patients are black, and the inheritance is usually autosomal recessive. Metastatic calcifications occur around joints. Laboratory findings typically show elevated serum phosphate levels. When symptomatic, the masses are excised. This lesion is benign and removal of normal tissue and radiation therapy are not necessary.