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10. Pathology and Oncology MCQs

Practice Set 108 of 351

This practice set contains high-yield board review questions covering key concepts in 10. Pathology and Oncology. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 2141

Topic: 10. Pathology and Oncology

Which of the following diagnostic studies best distinguishes Ewing's sarcoma from small cell osteosarcoma?

Basic Science 2005 Practice Questions: Set 1 (Solved) - Figure 34

. Bone scan
. Cytogenetics
. DNA ploidy analysis
. Sentinel node biopsy
. L-lactate dehydrogenase (LDH)

Correct Answer & Explanation

. Cytogenetics

Explanation

Cytogenetics best demonstrates the 11;22 translocation characteristic of Ewing's sarcoma. The translocation also can be detected with polymerase chain reaction and fluorescent in situ hybridization. The Ewing antibody is used for immunostaining to check for cell membrane (surface) staining of a marker unrelated to the translocation; this could also help distinguish Ewing's sarcoma from small cell osteosarcoma. A bone scan will show increased uptake with both types of tumors. Although most Ewing's sarcoma tumors are diploid, some are polyploid as are most osteosarcomas. Flow cytometry is used to sort cells, sometimes based on antibody binding. LDH can be elevated in both Ewing's sarcoma and osteosarcoma and is a poor prognostic indicator when elevated. Lymph node metastases are uncommon in both of these tumors. Perotti D, Corletto V, Giardini R, Parafioriti A, Fossati-Bellani F, Luksch R: Retrospective analysis of ploidy in primary osseous and extraosseous Ewing family tumors in children. Tumori 1998;84:493-498. Riley RD, Burchill SA, Abrams KR, Heney D, Sutton AJ, Jones DR, et al: A systematic review of molecular and biological markers in tumours of the Ewing's sarcoma family. Eur J Cancer 2003;39:19-30.

Question 2142

Topic: 10. Pathology and Oncology

A 13-year-old girl has had right groin pain for the past 3 weeks. She denies any history of trauma. Examination of the hip reveals no palpable soft-tissue mass or lymphadenopathy, and there is full range of motion. A plain radiograph and MRI scan are shown in Figures 15a and 15b. Biopsy specimens are shown in Figures 15c and 15d. What is the most likely diagnosis?

. Fibrous dysplasia
. Osteosarcoma
. Ewing's sarcoma
. Periosteal chondroma
. Aneurysmal bone cyst

Correct Answer & Explanation

. Fibrous dysplasia

Explanation

Fibrous dysplasia frequently occurs in the proximal femur. Microfractures and remodeling can lead to the classic "Shepherd's crook deformity." The lesion has a ground-glass appearance on plain radiographs. The histologic appearance shows proliferating fibroblasts in a loose spindle cell background. Dysplastic metaplastic trabeculae are arranged in an irregular or "Chinese letter" appearance. Enneking WF, Gearen PF: Fibrous dysplasia of the femoral neck: Treatment by cortical bone grafting. J Bone Joint Surg Am 1986;68:1415-1422.

Question 2143

Topic: 10. Pathology and Oncology

A 69-year-old woman reports a painful clicking in her right shoulder. A soft-tissue mass is palpated at the lower portion of the scapula. Based on the MRI scan and biopsy specimens shown in Figures 72a through 72c, what is the most likely diagnosis?

. Lymphoma
. Malignant fibrous histiocytoma
. Synovial sarcoma
. Fibromatosis
. Elastofibroma

Correct Answer & Explanation

. Elastofibroma

Explanation

Elastofibroma is a rare, benign soft-tissue pseudotumor characteristically located in the subscapular region. Most patients are between 50 and 70 years of age and have pain, decreased shoulder range of motion, or a mass. The lesion usually is best visualized with the arm elevated forward and adducted to displace the scapula laterally and allow the mass to protrude from the chest wall. They are frequently bilateral. Grossly, the mass is ill-defined, oblong or spherical, firm, and ranges in size from 5 cm to 10 cm. These masses appear infiltrative and frequently are mistaken for a sarcomatous lesion. Histologically, the mass is composed of a mixture of intertwining eosinophilic collagen and elastic fibers, and scattered fibroblasts, mucoid material, and fat. Vastamaki M: Elastofibroma scapulae. Clin Orthop Relat Res 2001;392:404-408. Nielsen T, Sneppen O, Mykre-Jensen O, et al: Subscapular elastofribroma: A reactive pseudotumor. J Shoulder Elbow Surg 1996;5:209-213.

Question 2144

Topic: 10. Pathology and Oncology

An otherwise healthy 16-year-old dancer reports a 1-month history of leg pain. AP and lateral radiographs of the distal femur are shown in Figures 67a and 67b. What is the next most appropriate step in management?

. Immobilization/casting
. Rest, limited weight bearing, and repeat radiographs in 4 weeks
. MRI of the femur
. Biopsy
. Chemotherapy

Correct Answer & Explanation

. MRI of the femur

Explanation

The radiographs show a very ill-defined, aggressive, moth-eaten bony destruction involving the distal left femoral diaphysis just above the metaphyseal junction. The differential diagnosis includes Ewing's sarcoma, osteosarcoma, lymphoma of bone, eosinophilic granuloma, osteomyelitis, and others. MRI would further define the lesion, and soft-tissue and intramedullary extension. There is aggressive periosteal reaction in the posteromedial aspect of the adjacent lesion with some multilayered components in the distal interface of the periosteum. The lateral radiograph shows cortical penetration and irregular periosteal reaction of the posterior margin, suggesting some posterior soft-tissue extension at this site as well. Gebhardt MC, Ready JE, Mankin HJ: Tumors about the knee in children. Clin Orthop Relat Res 1990;255:86-110.

Question 2145

Topic: 10. Pathology and Oncology

A 64-year-old man has had increasing pain in the left hip for the past 6 months. A radiograph and MRI scan are shown in Figures 25a and 25b. Biopsy specimens are shown in Figures 25c and 25d. What is the recommended treatment?

. Chemotherapy and internal hemipelvectomy
. Chemotherapy and hindquarter amputation
. Radiation therapy and internal hemipelvectomy
. Radiation therapy and hindquarter amputation
. Hindquarter amputation or internal hemipelvectomy

Correct Answer & Explanation

. Hindquarter amputation or internal hemipelvectomy

Explanation

The radiograph shows a lytic lesion in the left periacetabular area consistent with chondrosarcoma. A large soft-tissue mass is present along with extension through the supra-acetabular region and pubic ramus. The histology shows a hypercellular lesion infiltrating through the bony trabeculae with a basophilic cytoplasm. This is classified as a grade 2 chondrosarcoma. The treatment of a pelvic chondrosarcoma is wide resection via either an internal hemipelvectomy or amputation. Chondrosarcoma requires surgical resection for control and does not traditionally respond to chemotherapy or external beam irradiation therapy. Pring M, Weber, KL, Unni KK, et al: Chondrosarcoma of the pelvis: A review of sixty-four cases. J Bone Joint Surg 2001;83:1630-1642.

Question 2146

Topic: Bone Tumors

A 23-year-old woman reports right knee pain and fullness. The pain is worse with activity but also present at rest. Radiographs are shown in Figures 20a and 20b. What is the most likely diagnosis?

. Osteosarcoma
. Chondroblastoma
. Stress fracture
. Posttraumatic changes
. Chondrosarcoma

Correct Answer & Explanation

. Osteosarcoma

Explanation

The radiographs reveal a predominantly lytic, destructive lesion of the distal femur, although there is a hint of some blastic change as well. The lesion has violated the cortex, and there is mineralization outside the cortex laterally. The lateral radiograph suggests a soft-tissue density. These aggressive changes on radiographs in this age group are strongly suggestive of osteosarcoma. Sanders TG, Parsons TW: Radiographic imaging of musculoskeletal neoplasia. Cancer Control 2001;8:221-231.

Question 2147

Topic: 10. Pathology and Oncology

Which of the following malignant tumors most commonly contains soft-tissue calcifications seen on radiographs or CT?

Basic Science Board Review 2008: High-Yield MCQs (Set 2) - Figure 21

. Hemangioma
. Ewing's sarcoma
. Clear cell sarcoma
. Malignant fibrous histiocytoma
. Synovial sarcoma

Correct Answer & Explanation

. Synovial sarcoma

Explanation

Focal calcifications causing small radiopacities are found in 15% to 20% of synovial sarcomas. Their irregular contours differentiate them from the phleboliths found in a benign hemangioma. Ewing's sarcoma, clear cell sarcoma, and malignant fibrous histiocytoma do not commonly have calcifications within the lesions. Enzinger FM, Weiss SW: Soft Tissue Tumors, ed 3. St Louis, MO, Mosby, 1995, p 761.

Question 2148

Topic: 10. Pathology and Oncology

A 16-year-old boy has had left knee pain and swelling after sustaining a minor twisting injury while playing basketball 2 weeks ago. Figures 5a through 5e show the radiograph, MRI scans, and biopsy specimens. What is the most likely diagnosis?

. Osteomyelitis
. Tuberculosis
. Osteosarcoma
. Ewing's sarcoma
. Malignant fibrous histiocytoma (MFH)

Correct Answer & Explanation

. Ewing's sarcoma

Explanation

The imaging studies and histology are most consistent with Ewing's sarcoma. Tuberculosis can show small round blue cells on histology (lymphocytes associated with chronic infection) but would more typically involve the knee joint and periarticular bone. Osteosarcoma and MFH do not have small round blue cells histologically. Sissons HA, Murray RO, Kemp HBS: Orthopaedic Diagnosis. Berlin, Springer-Verlag, 1984, pp 254-256.

Question 2149

Topic: Bone Tumors

Mutations of what gene are associated with the subsequent development of osteosarcoma?

. RB
. EWS-FLI1
. EGF-R
. IGF-R
. VEGF

Correct Answer & Explanation

. RB

Explanation

Patients with a mutation of the retinoblastoma gene (RB) have an increased likelihood for the development of osteosarcoma. The EWS-FLI1 gene is the fusion product of a chromosomal translocation of 11:22. EGF-R and IGF-R are growth factor receptors, but mutations in these genes have not been correlated with osteosarcoma. VEGF is a proangiogenic molecule that is involved in tumor formation in multiple sites but not the development of osteosarcoma. Scholz RB, Kabisch H, Delling G, et al: Homozygous deletion within the retinoblastoma gene in a native osteosarcoma specimen of a patient cured of a retinoblastoma of both eyes. Pediatr Hematol Oncol 1990;7:265-273.

Question 2150

Topic: 10. Pathology and Oncology

A 21-year-old man has had posterior neck discomfort for the past 6 months. A whole-body bone scan and a cervical single-photon emission CT reveal increased activity at the C7 spinous process. MRI reveals multifocal involvement of the spinous process lamina and facet of C7. A CT-directed needle biopsy reveals osteoblastoma. What is the best course of action?

. Observation
. Radiation therapy
. Curettage
. En bloc excision with stabilization
. En bloc excision followed by radiation therapy

Correct Answer & Explanation

. En bloc excision with stabilization

Explanation

En bloc excision is the recommended treatment of osteoblastoma. Treatment should consist of en bloc removal of the lamina, facet, and spinous process. Facet removal would necessitate fusion. Radiation therapy is not recommended. Intralesional curettage has a high rate of recurrence. Bridwell KH, Ogilvie JW: Primary tumors of the spine, in Bridwell KH, DeWald RL (eds): The Textbook of Spinal Surgery. Philadelphia, PA, JB Lippincott, 1991, vol 2, pp 1143-1174.

Question 2151

Topic: 10. Pathology and Oncology

A 37-year-old man pulled his hamstring playing softball 3 weeks ago. The patient had not noted any mass prior to his injury. MRI scans of the posterior thigh are shown in Figures 4a and 4b. Figure 4c shows the biopsy specimen from a needle biopsy. What is the most likely diagnosis?

. Intramuscular hematoma
. Lipoma
. Myositis ossificans
. Malignant fibrous histiocytoma
. Liposarcoma

Correct Answer & Explanation

. Malignant fibrous histiocytoma

Explanation

Malignant fibrous histiocytoma (MFH) is the most common soft-tissue sarcoma. MFH typically presents as a large mass, deep to the fascia with heterogeneous signal on MRI. The MRI scans show a heterogeneous lesion in the posterior thigh. There is significant high signal uptake on the T2-weighted image. The histology shows malignant histiocytic cells with marked atypia and pleomorphism. Histology of a hematoma would show only old hemorrhage and some granulation tissue. Lipoma and liposarcoma are both seen as a fat-containing lesion on histology. No significant fat tissue is seen in this histologic specimen. Histology of myositis ossificans would show bone formation. Simon SR (ed): Orthopaedic Basic Science. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1994, pp 219-276.

Question 2152

Topic: 10. Pathology and Oncology

A 28-year-old woman has had pain in her hand and mild swelling of the little finger for the past 2 months. A radiograph is shown in Figure 41a, and the biopsy specimen is shown in Figures 41b and 41c. What is the most likely diagnosis?

. Osteochondroma
. Osteomyelitis
. Ollier's disease
. Brown tumor
. Enchondroma

Correct Answer & Explanation

. Enchondroma

Explanation

The radiographic appearance shows a slightly expansile lesion in the proximal phalanx of the fifth digit typical of an enchondroma. There is a stippled appearance within the bone and no evidence of cortical destruction. The biopsy reveals a cartilage lesion with basophilic cytoplasm. There are some hypercellular areas but no evidence of pleomorphism. Enchondromas in the tubular bones of the hand are usually more cellular than their counterparts in the femur and humerus and should not be considered malignant. No other lesions are noted in the radiograph, so a diagnosis of Ollier's disease cannot be made. An osteochondroma is a benign surface cartilage tumor. Brown tumor and osteomyelitis can be differentiated from enchondroma based on the histology. Wold LE, Adler CP, Sim FH, et al: Atlas of Orthopedic Pathology, ed 2. Philadelphia, PA, WB Saunders, 2003, p 225.

Question 2153

Topic: 10. Pathology and Oncology

An 8-year-old girl has had a painless enlarging mass of insidious onset in the left thigh for the past 3 weeks. Her mother denies any history of trauma, fever, or disease. Examination reveals a nontender, mobile mass in the left medial thigh. Her gait is normal. Figures 25a through 25d show the frog-lateral radiograph, the axial and coronal T1-weighted MRI scans, and the axial T2-weighted MRI scan. Biopsy results reveal a nonrhabdomyosarcoma soft-tissue sarcoma. The most appropriate treatment should consist of

. radiation therapy and chemotherapy.
. surgical drainage and antibiotics.
. surgical excision with chemotherapy and/or radiation therapy.
. proximal femoral resection, allograft prosthetic reconstruction, and chemotherapy.
. serial observation with repeat MRI in 3 months.

Correct Answer & Explanation

. surgical excision with chemotherapy and/or radiation therapy.

Explanation

In childhood, the more common soft-tissue sarcomas are rhabdomyosarcoma, synovial sarcoma, and fibrosarcoma. Rhabdomyosarcoma, treated with radiation therapy and chemotherapy, is a round cell tumor and is inconsistent with this patient's histologic findings. Synovial sarcoma can be monophasic or biphasic with both spindle and epithelial-like cells and is associated with the characteristic reciprocal chromosomal translocation of t(x:18)(p11;q11) which is not found in fibrosarcoma. Synovial sarcoma also can be associated with cystic loculated areas best seen in a T2-weighted MRI scan. Nonrhabdomyosarcoma childhood soft-tissue sarcomas are treated with surgical excision in conjunction with chemotherapy and/or radiation therapy. The histology reveals no inflammatory cells to suggest an abscess; therefore, antibiotics and drainage are unnecessary. The MRI scans clearly show a mass of soft tissue and no bone involvement; therefore, proximal femoral resection is not appropriate. Serial observation is not appropriate because of the history of enlargement and insidious onset. Enzinger FM, Weiss SW: Soft Tissue Tumors, ed 3. St Louis, MO, Mosby Year Book, 1995, p 757.

Question 2154

Topic: 10. Pathology and Oncology

Figures 1a and 1b show the sagittal T2- and T1-weighted MRI scans of a 25-year-old intravenous drug abuser who has low back pain that is increasing in intensity. Laboratory studies show a WBC count of 10,000/mm3 and an erythrocyte sedimentation rate of 80 mm/h. Blood culture is negative. Initial management consist of

. CT-guided closed biopsy.
. open surgical biopsy.
. antibiotic coverage for Staphylococcus aureus.
. broad-spectrum antibiotic coverage.
. a follow-up MRI scan in 8 weeks.

Correct Answer & Explanation

. CT-guided closed biopsy.

Explanation

The MRI scans show vertebral diskitis/osteomyelitis. The treatment of spinal infection in adults should be organism specific; therefore, initial management should consist of CT-guided closed biopsy prior to administration of antibiotic coverage. An open biopsy is indicated for a failed closed biopsy or failure of nonsurgical management. Although Staphylococcus aureus is the most common bacteria, a history of intravenous drug abuse raises suspicion for other organisms, including Pseudomonas. Tay BK, Deckey J, Hu SS: Spinal Infections. J Am Acad Orthop Surg 2002;10:188-197.

Question 2155

Topic: 10. Pathology and Oncology

A 37-year-old man has left shoulder pain and weakness. Coronal T1- and axial T2-weighted MRI scans are shown in Figures 17a and 17b. The biopsy specimen is shown in Figure 17c. What is the most likely diagnosis?

. Abscess
. Ganglion cyst
. Nerve sheath tumor
. Lymphoma
. Metastatic cancer

Correct Answer & Explanation

. Ganglion cyst

Explanation

A ganglion cyst arising from the posterior labrum of the shoulder is a known cause of suprascapular nerve impingement. The MRI characteristics of low-signal intensity on T1 and high-signal intensity on T2 are seen in lesions with a high fluid content. The histology shows a cavity with a thin fibrous lining. Ferrick MR, Marzo JM: Suprascapular entrapment neuropathy and ganglion cysts about the shoulder. Orthopedics 1999;22:430-434.

Question 2156

Topic: 10. Pathology and Oncology

Figures 27a through 27c show the AP radiograph, MRI scan, and biopsy specimen of an otherwise healthy man who has a painful wrist. Serum chemistry studies are normal. What is the most likely diagnosis?

. Aneurysmal bone cyst
. Giant cell tumor
. Renal cell carcinoma
. Osteomyelitis
. Brown tumor

Correct Answer & Explanation

. Giant cell tumor

Explanation

The osseous sites most frequently involved by giant cell tumor of bone are the distal femur, proximal tibia, and distal radius with approximately 10% of giant cell tumors involving the distal radius. The goals of treatment are to remove the tumor completely and to preserve maximum function of the extremity.

Question 2157

Topic: 10. Pathology and Oncology

Figures 24a through 24c show the coronal T1-weighted, T2-weighted fat-saturated, and T1-weighted fat-saturated gadolinium MRI scans of the proximal thigh of a 52-year-old woman who reports a mass in the medial thigh and groin area. She notes that the fullness has grown in size over the course of many months. Based on these findings, what is the most likely diagnosis?

. Malignant fibrous histiocytoma
. Liposarcoma
. Synovial cell sarcoma
. Leiomyosarcoma
. Clear cell sarcoma

Correct Answer & Explanation

. Liposarcoma

Explanation

The images show a complex, lobular lesion of the thigh that has signal characteristics that follow fat. The size of the lesion, the areas of stranding within the mass, along with mild uptake on the gadolinium sequences and the mild edema within the lesion on the T2-weighted image make liposarcoma the most likely diagnosis and simple intramuscular lipoma far less likely. All other diagnoses listed would not follow fat characteristics shown on the MRI sequences.

Question 2158

Topic: 10. Pathology and Oncology

Figures 12a and 12b show the radiographs of a 50-year-old patient who reports acute knee pain after sustaining a twisting injury while playing tennis. Examination is unremarkable. The next most appropriate step in management should consist of

. observation.
. a biopsy.
. CT of the chest.
. MRI of the femur.
. wide local excision.

Correct Answer & Explanation

. observation.

Explanation

The radiographs show localized diffuse cortical thickening that is characteristic of melorheostosis. The condition may be monostotic or it may involve many bones in one extremity (monomelic) in the distribution of a sclerotome. Bone scans will show increased uptake at the site or sites of skeletal involvement. Long tubular bones are most commonly involved. Melorheostosis is usually asymptomatic and requires no treatment. On rare occasions, there may be associated soft-tissue contractures. Dorfman H, Czerniak B: Bone Tumors. St Louis, MO, Mosby Inc, 1998, pp 1105-1107. Campbell CJ, Papademetriou T, Bonfiglio M: Melorheostosis: A report of the clinical, roentgenographic, and pathological findings in fourteen cases. J Bone Joint Surg Am 1968;50:1281-1304.

Question 2159

Topic: 10. Pathology and Oncology

A 7-year-old boy has had chronic left leg pain that is worse at night but is not activity related. Use of nonsteroidal anti-inflammatory drugs for the past 6 months has failed to provide relief. A CBC count with differential, erythrocyte sedimentation rate, and C-reactive protein are within normal limits. Radiographs and a CT scan are shown in Figures 31a through 31c. Management should consist of

. intralesional curettage followed by 6 weeks of parenteral antibiotics.
. local curettage and autogenous bone graft.
. neoadjuvant chemotherapy followed by surgical resection and additional chemotherapy.
. percutaneous radiofrequency coagulation.
. closed needle biopsy.

Correct Answer & Explanation

. percutaneous radiofrequency coagulation.

Explanation

Osteoid osteomas are painful bone lesions, with radiographs revealing a dense sclerotic cortex surrounding a small radiolucency or nidus. Symptoms often are worse at night but usually are not activity related. While treatment in the past has consisted of open en bloc excision, current means of removal include percutaneous drilling under CT guidance and percutaneous radiofrequency coagulation. Success rates of percutaneous treatment are comparable to those seen following open procedures. The characteristic radiographic appearance of this lesion usually obviates the need for biopsy. Because the lesion is not caused by pyogenic organisms, antibiotics are not indicated. Donahue F, Ahmad A, Mnaymneh W, Pevsner NH: Osteoid osteoma: Computed tomography guided percutaneous excision. Clin Orthop 1999;366:191-196.

Question 2160

Topic: 10. Pathology and Oncology

Figures 20a and 20b show the AP and lateral radiographs of a 62-year-old man who has had hip pain for the past 3 weeks. Figure 20c shows a CT scan of the abdomen and pelvis. A needle biopsy specimen is shown in Figure 20d. Preoperative management should include which of the following?

. Lymphocentigraphy
. Colonoscopy
. Bronchoscopy
. Embolization of the femoral lesion
. Bone marrow aspiration

Correct Answer & Explanation

. Embolization of the femoral lesion

Explanation

The histology shows findings consistent with metastatic renal cell carcinoma. Renal cell carcinoma metastases are extremely vascular. Preoperative embolization helps minimize the amount of blood loss during curettage of these lesions. Chatziioannou AN, Johnson ME, Pneumaticos SG, et al: Preoperative embolization of bone metastases from renal cell carcinoma. Eur Radiol 2000;10:593-596.

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